AUGUST 2000
MD1640A
MD1641A
Series II Modem 336
Series II Modem 336+
CUSTOMER
SUPPORT
INFORMATION
Order toll-free in the U.S.: Call 7877-877-BBOX (outside the U.S. call 724-746-5500)
FREE technical support 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746
Mailing address: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com
•
Email: [email protected]
SERIES II INTELLIGENT DATA/FAX MODEMS
DISCLAIMER
This publication may not be reproduced, in whole or in part, without prior
expressed written permission from the manufacturer. The manufacturer
makes no representations or warranties with respect to the contents hereof
and specifically disclaims any implied warranties of merchantability or fitness
for any particular purpose. The manufacturer reserves the right to revise this
publication and to make changes from time to time in the content hereof
without obligation of the manufacturer to notify any person or organization
of such revisions or changes.
TRADEMARKS USED IN THIS MANUAL
MNP and Microcom Network Protocol are trademarks of Microcom Inc.
AS/400 and System3x are registered trademarks of IBM.
Appletalk, Mac, and Macintosh are registered trademarks of Apple
Computer Inc.
Unix is a registered trademark of X/Open Co. Ltd.
Microsoft and Windows are registered trademarks of Microsoft Corporation.
All other trademarks mentioned in this manual are the property of their
respective owners.
2
Table of Contents
Contents
Chapter 1 - Introduction and Description
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
Introduction............................................................................7
How To Use This Manual ......................................................7
What is in Your Modem Package? ......................................10
Modem Features ..................................................................10
Fax Features ..........................................................................11
Technical Specifications ......................................................12
Power ....................................................................................16
Modem LED Indicators ......................................................16
Controls on PC Board..........................................................18
Chapter 2 - Installation and Connection
2.1
2.2
2.3
2.4
Safety Warnings ....................................................................19
Installation ............................................................................20
Is Your Series II Modem Ready for Use? ............................23
Operating Your Series II Modem ......................................24
2.4.1
Simple Operations ......................................................25
2.5
The Answer/Originate - Voice/Data Toggle Switch..........25
Chapter 3 - Software Configuration
3.1
3.2
Introduction ........................................................................26
Serial Port Limitations ........................................................26
3.2.1
3.2.2
How Can You Identify Your UART Type?....................27
The 16550 UART and Windows 3.1 ............................28
3.3
3.4
Configuring Your Software ..................................................29
3.3.1
Configuring Software for Your Modem ......................29
PC Initialization Strings ......................................................30
3.4.1
3.4.2
Changing Default Parameters......................................30
Other Parameters ........................................................31
3.5
3.6
Macintosh Initialization ......................................................31
Configuring Software for Your Computer..........................32
3.6.1
Configuring Software for the Remote System ............32
Terminal Emulation......................................................33
File Transfer Protocols ..................................................33
3.6.2
3.6.3
3
SERIES II INTELLIGENT DATA/FAX MODEMS
3.7
When to Disable Data Compression ..................................33
3.7.1 Disabling Error Correction ..........................................34
Chapter 4 - Manual Dial and Automatic Answer
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
Introduction ........................................................................35
Dialing/On-Line/Answering ..............................................35
Auto. Leased Line Restoral Operation (336+ Only) ........37
Manual Dial Backup Call Termination (336+ Only) ........37
Dial Backup and Leased Line Restoral (336+ Only) ........37
Dial-Up Operation (336+ Only)..........................................39
Manual Call Origination......................................................39
Automatic Answering ..........................................................40
Manual Answering................................................................41
Handshaking Details ............................................................41
Call Termination ..................................................................42
Chapter 5 - Command Mode
5.1
Introduction..........................................................................44
5.1.1
5.1.2
AT Command Editing ..................................................44
Functional Modes..........................................................45
5.2
5.3
5.4
Summary of AT Commands ................................................46
Result Codes ........................................................................50
Dialing Commands ..............................................................52
5.4.1
Dialing Action Commands ..........................................52
Dial Modifier Commands ............................................54
Phone Number Memory Commands ..........................58
Configuration and Default Storage Commands ........60
Command Response (Result Code) Commands........63
Phone Line Conditioning Commands ........................66
RS232C Interface Control Commands........................68
Error Correction Commands ......................................70
Flow Control Commands..............................................75
5.4.2
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
5.4.8
5.4.9
5.4.10 Compression, Error Correction, Flow Control,
Pass-Through and Pacing Commands ........................81
5.4.11 Speed Conversion Commands ....................................82
4
Table of Contents
5.4.12 Immediate Action Commands ....................................85
5.4.13 Line Probe Commands ................................................90
Chapter 6 - S-Registers
6.1
6.2
Introduction..........................................................................92
Reading and Assigning S-Register Values ..........................102
6.2.1
6.2.2
Examples of Assigning Values ......................................102
Examples of Reading Values ........................................103
6.3
AT Command and S-Register Summary ............................103
Chapter 7 - Callback Security and Remote
Configuration
7.1
7.2
7.3
Introduction..........................................................................104
Callback Feature Description ..............................................104
Remote Configuration Description ....................................105
7.3.1
Initial Setup Procedures for Callback and Remote ..
Configuration. ..............................................................105
Remote Configuration Procedures..............................111
7.3.2
7.4
7.5
Remote Configuration and Callback Security AT ............
Commands ..........................................................................112
Remote Configuration/Callback Security S-Registers ......114
Chapter 8 - Modem Testing
8.1
8.2
8.3
8.4
8.5
8.6
8.7
Introduction ........................................................................116
Local Analog Loopback Test/V.54 Loop 3 ........................117
Digital Loopback Test/V.54 Loop 2 (Local/Manual) ......118
Digital Loopback Test/V.54 Loop 2 (Remote/Auto.) ......120
Back-to-Back Test..................................................................121
Synchronous Mode Testing ................................................123
Local Analog Loopback Test (Synchronous Mode)..........123
5
SERIES II INTELLIGENT DATA/FAX MODEMS
8.8
8.9
Digital Loopback Test (Local/Manual) (Sync Mode) ......124
Digital Loopback Test (Remote/Auto.) (Sync Mode) ......125
Chapter 9 - DIP-Switch Settings
9.1
9.2
9.3
9.4
Introduction..........................................................................127
DIP-Switch Option Settings ................................................128
Speaker Volume Control ....................................................136
Recording Option Configurations......................................137
Appendix A - Troubleshooting
A.1
A.2
Possible Causes and Solutions ............................................139
Contacting Black Box ..........................................................147
A.2.1 Recording Modem Information ..................................147
A.2.2 Making the Call ............................................................148
Shipping and Packaging ......................................................148
Upgrading the Series II Modem’s Firmware......................149
A.3
A.4
Other Appendixes
Appendix B - Dial Pulse and Tone-Dial Frequencies ......................150
Appendix C - Command Summary ..................................................151
Appendix D - DIP-Switch Summary ..................................................164
Appendix E - S-Register Summary ....................................................167
Appendix F - Result Code Summary ................................................171
Appendix G - V.25bis Operation........................................................174
Appendix H - Series II Modem Cables..............................................187
Appendix I - RS232C Interface Specifications ................................189
Appendix J - Regulatory Information ..............................................195
6
CHAPTER 1: Introduction and Description
1. Introduction and Description
1.1 Introduction
Welcome to the world of data communications. You have acquired one
of the finest intelligent desktop data/fax modems available today, a
Series II Modem from Black Box. Your Series II Modem provides data
communication at 33,600-14,400 bps (Enhanced V.34/V.32bis), as well
as other prevalent datacomm standards. The Modem supports adaptive
®
protocol enhancing used in typical Unix batch file transfers and
®
®
support for IBM's AS/400 and System/3X environment. If your
Series II Modem is a 336+ model, it also performs dial backup with
automatic lease line restoration. This Owner’s Manual will help you
install, configure, test and use your Modem.
1.2 How To Use This Manual
This manual is divided into nine chapters. There are also several
appendices at the end of this manual, most of which repeat information
contained in the chapters, but in a more condensed form. These appen-
dices can be used as a quick reference. The information contained in
each chapter and appendix is as follows:
Chapter 1 - Introduction and Description
This chapter begins with a short introduction, followed by a guide (which
you are now reading) to the use of this manual. There is a discussion
about what components you can expect in your Series II Modem
package. We then provide a more detailed description of the modem,
including the modem’s technical specifications. Chapter 1 includes
sections covering power, LED indicators and a brief summary of PC
board controls. (Chapter 9 covers switch settings more thoroughly.)
7
SERIES II INTELLIGENT DATA/FAX MODEMS
Chapter 2 - Installation and Connection
Chapter 2 covers the procedure for connecting the Series II Modem to
your computer and to the phone line. Details are given, supported by
illustrations on the Modem's back panel connections as a guide to
install your Modem to the point of operation.
Chapter 3 - Software Configuration
Chapter 3 documents communication software configuration
recommended specifically for the Series II Modem. There is also some
discussion of how to identify the limitations and capabilities of your
computer before the software installation process is done. Other issues
covered include setting up initialization strings, changing default
parameters, configuring software for the remote system and file
transfer protocols.
Chapter 4 - Manual Dial and Automatic Answer
This chapter covers some modem operations, but delays discussion on
Command Mode operation until Chapter 5. Automatic Leased Line
Restoration, Dial backup, Manual Dial Mode, and Answer Mode opera-
tion are covered in detail, as well as the handshaking procedures
employed between two modems in an auto-answer application.
Chapter 5 - AT Command Mode Operation
This may be the most important chapter of this manual. It begins with
an introduction and discussion on Command Mode fundamentals. A
flow chart is provided to illustrate Command Mode and On-Line Mode
operation and the methods used in each mode. Next, there is a
summary of the modem’s commands and responses. We then go into
a detailed explanation of each Series II Modem command, providing
examples where applicable.
Chapter 6 - S-Registers
Chapter 6 covers the Series II Modem's S-Registers, which enable the
user to establish, read, and modify various modem options. All of the
S-Registers are charted and explained, followed by instructions on
accessing the S-Registers and reading or changing their values.
8
CHAPTER 1: Introduction and Description
Chapter 7 - Callback and Remote Configuration
Chapter 7 documents instructions on how to operate the Series II
Modem's Callback and Remote Configuration features; and the usage of
LOGIN Passwords, Set-Up Passwords and Remote Escape Characters as
network management tools.
Chapter 8 - TestingYour Modem
This Chapter covers the modem's built-in test features. These are:
Power-on Self Test, Back-To-Back Test, Local Analog Loopback, Digital
Loopback and Remote Digital Loopback Tests. We have included a
description of each test and how to use each test procedure.
Chapter 9 - DIP-Switches
The Series II Modem printed-circuit board options are covered in this
chapter. Sixteen DIP-Switch settings and the modem's speaker volume
control are explained in detail, including all default settings.
Appendix A - Troubleshooting
Appendix B - Pulse Dial and Tone-Dial Frequencies
Appendix C - AT Command Summary
Appendix D - DIP Switch Summary
Appendix E - S-Register Summary
Appendix F - Result Code Summary
Appendix G - V.25bis Operation
Appendix H - Series II Modem Cables
Appendix I - RS232 Interface Specifications
Appendix J - Regulatory Information
9
SERIES II INTELLIGENT DATA/FAX MODEMS
1.3 What is inYour Modem Package?
Your Series II Modem is made up of many components. Make sure you
have them all before trying to operate your modem. Your package
should include:
•
•
•
•
•
The Series II Modem itself
AC Power Transformer
(2) RJ-11 to RJ-11 telephone cords
This Owner’s Manual
336+ (MD1640A) only: (1) RJ-11 to spade lugs leased-line cable
If any of these items are missing, please contact Black Box.
1.4 Modem Features
Your Series II Modem meets the proposed Enhanced V.34 ITU standard
for data signalling rates as high as 33.6/31.2K bps in full duplex mode.
Connections can be made on Public Switched Telephone Networks
(PSTNs) and/or point-to-point 2-wire and 4-wire leased telephone type
circuits. Enhanced V.34 is an extension of V.32/V.32bis/V34 standards,
and supports and is compatible with those features, including EIA
extended Automode; adaptive line probing; automatic symbol rate and
carrier frequency during start-up; and retrain and rate renegotiation
(in 2400 bps increments).
Your modem is compatible with the AT command set and the ITU
V.25 bis standard for sunchronous dialing. It also features ITU V.42
error correction and V.42bis data compression, providing 100% error-
free data transmission. V.42 error correction incorporates MNP (Classes
3 and 4) and LAP-M. You may select V.42bis data compression for 4-1
throughput, or MNP Class 5 for 2-1 throughput.)
10
CHAPTER 1: Introduction and Description
Your Series II Modem offers interactive automatic dialing, as well
as Command Mode option configuration. You may store up to ten
command line/telephone numbers, of up to 60 characters each, in
the modem’s nonvolatile memory. The modem pulse or tone dials,
and recognizes dial tones and busy signals for reliable call-progress
detection. The modem can detect AT&T calling card tones. It is
FCC-Registered for connection to telephone networks without any Data
Access Arrangements (DAA’s).
Your modem also features Callback Security to protect networks from
unauthorized use, and to manage phone line costs. By using the
modem’s phone number and password directory, a host site can, upon
receipt of a call, callback to a remote site at a predetermined number.
Remote Configuration permits you to assist users at remote sites, saving
you the time and trouble of site visits and preventing misinterpretation
of configuration instructions.
In addition, the major application for the 336+ (MD1640A) model of
the Series II Modem is in 4-wire leased line networks with the addition
of dial backup capability. With this capability, the dialup feature
prevents downtime if the leased line fails. Since the Modem operates
according to ITU V.34 modulation, it can operate full-duplex over two
wires, so that the dial backup mode performs the same throughput as
the leased line.
1.5 Fax Features
Your Series II Modem meets the ITU V.17 standard for sending and
receiving faxes. When linked to a compatible fax machine or modem,
it can transmit faxes at 14,4 K bps. It also meets the ITU’s Group 3
Designation for sending and receiving faxes at 9600 bps; and Group 2
Designation for sending and receiving faxes at 4800 bps. The Modem is
also downward-compatible with modems to speeds as low as 300 bps, so
it can send and receive faxes with any fax machine in the world.
11
SERIES II INTELLIGENT DATA/FAX MODEMS
1.6 Technical Specifications
Your Series II Modem data/fax modem meets the specifications listed
below:
Data Rates (modem)
33,600, 31,200, 28,800, 26,400, 24,000,
21,600, 19,200, 16,800, 14,400, 12,000, 9600,
7200, 4800, 2400, 1200, 0-300 bps
Data Rates (fax)
Data Format
14,400, 9600, 7200, 4800 bps
Serial, binary, asynchronous at 0-300, 1200,
2400, 4800, 7200, 9600, 12,000, 14,400,
16,800, 19,200, 21,600, 24,000, 26,400,
28,800, 31,200, 33,600 bps; synchronous at
1200, 2400, 4800, 7200, 9600, 12,000,
14,400, 16,800, 19,200, 21,600, 24,000,
26,400, 28,800, 31,200, 33,600 bps
Compatibility
ITU V.42bis, V.42, Pending ITU Enhanced
V.34 approval, ITU V.34, ITU V.32bis, V.32,
V.22bis, V.22, V.25bis, Bell 212A and
103/113, ITU V.17, Group 3 T.4, T.30 and
EIA TR-29 Class 2
Error Correction
Data Compression
Speed Conversion
V.42 (LAP-M or MNP 3 & 4) error
correction
V.42bis, (4:1 throughput) or MNP 5
(2:1 throughput) data compression
Serial port data rates adjustable to 300,
1200, 2400, 4800, 9600, 19,200, 38,400,
57,600 and 115,200 bps
Flow Control
Options
Xon/Xoff, Hardware RTS/CTS, ENQ/ACK
Unix-to-Unix Copy Protocol (UUCP)
"Spoofing"
12
CHAPTER 1: Introduction and Description
Mode of Operation
Intelligent Features
Full duplex over both dial-up lines and
2-wire or (336+ [MD1640A] only) 4-wire
leased lines; automatic or manual dialing,
automatic or manual answer; and (336+
[MD1640A] only) automatic dial backup on
separate lines in leased line operation
Fully “AT command” compatible, micropro-
cessor controlled remote configuration, EIA
extended Automode, adaptive line probing,
automatic symbol rate and carrier
frequency during start-up, retrain and rate
renegotiation, autodial, redial, repeat dial,
dial linking, pulse or tone dial, dial tone
detection, dial pauses, call status display,
auto-parity and data rate selection,
keyboard-controlled modem options,
nonvolatile memory and on-screen displays
for modem option parameters and up to
ten telephone numbers/command lines of
up to 60 digits each, help menus
Command Buffer
Modulation
60 characters
Trellis Coded Modulation (TCM) at 33,600,
31,200, 28,800, 26,400, 24,000, 21,600,
19,200, 16,800, 14,400, 12,000 and 9600
bps, Quadrature Amplitude Modulation
(QAM) at 9600 (non-trellis), 4800 and 2400
bps, PSK at 1200 bps, FSK at 300 bps
Fax Modulations
V.21CH2 FSK at 300 bps
V.27ter DPSK at 4800 and 2400 bps
V.29 QAM at 9600 and 7200 bps
V.17 TCM at 14400, 12000, 9600,
and 7200 bps
13
SERIES II INTELLIGENT DATA/FAX MODEMS
Fax Carrier
V.21CH2 (Half Duplex)
Frequencies
1650Hz Mark, 1850Hz Space for Transmit
Originate
1650Hz Mark, 1850Hz Space for Transmit
Answer
V.27ter 1800Hz Originate/Answer
V.29 QAM 1700Hz Originate/Answer
V.17 TCM 1800Hz Originate/Answer
Lease Line Restoral
Carrier Frequencies
336+ (MD1640A) only: When in dial backup
mode, modem attempts leased line restoral
periodically (controlled by S-Register S18
setting)
1800 Hz V.32/V.32bis/V.34/Enhanced V.34:
33.6K/31.2K/28.8K/26.4K/24K/21.6K/
19.2K/16.8K/14.4K/12K/9.6K/7.2K/4.8K
Carrier Frequencies
2400 & 1200 bps
(V.22bis/V.22 or
Transmit Originate:
Transmit Answer:
Receive Originate:
Receive Answer:
1200 Hz
2400 Hz
2400 Hz
1200 Hz
Bell 212A Standard)
Carrier Frequencies,
1270 Hz Mark, 1070 Hz Space for
300 bps (Bell Standard) Transmit Originate
2225 Hz Mark, 2025 Hz Space for Receive
Originate
2225 Hz Mark, 2025 Hz Space for Transmit
Answer
1270 Hz Mark, 1070 Hz Space for Receive
Answer
Transmit Level
-11dBm (dial-up), -9 or -15 dBm (leased-
line); dBm level selectable with DIP-
Switch #3 in leased line setting
Frequency Stability
0.01%
14
CHAPTER 1: Introduction and Description
Receiver Sensitivity
AGC Dynamic Range
Interface
-43 dBm under worst case conditions
43 dB
EIA RS-232C/ITU V.24
Connectors
Both models: (1) DB25 female for RS232C,
(1) RJ-11 female for phone hadset, (1)
Power inlet;
336+ (MD1640A) model only: (1) RJ-11
female for dialup line, (1) RJ-11 female
for 2- or 4-wire leased line;
336 (MD1641A) model only: (1) RJ-11 female
for dialup line or 2-wire leased line
Diagnostics
Indicators
Power-on Self Test, Local Analog Loop,
Local Digital Loop, Remote Digital Loop,
Back-to-Back Test.
All front-mounted LEDs:
Both models: Transmit Data, Receive Data,
Carrier Detect, Speed Indicators, Off Hook,
Terminal Ready, Error Correction, and Fax;
336+ (MD1640A) model only: Error
Controls
Speaker
Toggle switches for Power and for
Voice/Data with Originate or Answer, DIP
Switches for various modem options, and
volume knob
Speaker for call progress monitoring
Operating Temperature 0˚ to 50˚C (32˚ to 120˚F)
Power Requirements
115-VAC, 60Hz, 0.3amp (2-prong outlet-
mounted transformer)
Dimensions
Weight
1.38"H x 6.2"W x 9"D (3.5 x 15.6 x 22.9 cm)
1.6 pounds (0.7 kg) without transformer,
2.6 pounds (1.2 kg) with transformer
15
SERIES II INTELLIGENT DATA/FAX MODEMS
1.7 Power
Power is supplied through an AC power transformer terminated with a
standard two-prong plug. The transformer supplies low voltage AC to
the modem, and plugs into any conventional 115 volt AC, 60 Hz, two-
prong power outlet. The power transformer supplied with the modem
is the only one that should be used. Use of any other transformer could
cause damage to the modem. A Power On/Off switch is located on the
back of the modem.
1.8 Modem LED Indicators
The Series II Modem has fourteen diagnostic LED indicators. They are:
Answ
Orig
SD
RD
CD
33.6
24.0
19.2
14.4
96
24
OH
TR
EC
FX
Voice/
Data
Send Rcv Carr 33.6K 24.0K 19.2K 14.4K 9600 2400 Off Hk Rdy V.42 Fax
Answ
Orig
SD
RD
CD
33.6
24.0
19.2
14.4
96
24
OH
TR
EC
FX
ERR
Voice/
Data
Send Rcv Carr 33.6K 24.0K 19.2K 14.4K 9600 2400 Off Hk Rdy V.42 Fax Error
Figure 1-1. LED Displays of the 336 (MD1641A, top)
and 336+ (MD1640A, bottom)
1) Transmit (Send) Data (SD). This LED blinks when data is being
transmitted, on for a space, off for a mark. The state of this LED
matches the TD circuit on Pin 2 of the RS-232C/V.24 interface.
2) Receive Data (RD). This LED blinks when data is being received,
on for a space, off for a mark. The state of this LED matches that of
the RD circuit on Pin 3 of the RS-232C/V.24 interface.
3) Carrier Detect (CD). This LED is lit when a valid carrier tone
has been detected.
16
CHAPTER 1: Introduction and Description
4) 28,800 bps (28.8). This LED behaves differently depending on your
connection:
• When the modem is connected at 33,600 bps, it blinks 5 times/sec.;
• When the modem is connected at 31,200 bps, it blinks once/sec.;
• When the modem is connected at 28,800 bps, it is solidly lit.
Note: if the modem falls back to 26.4K bps while in V.34 mode,
both the 28.8 and 24.0 LEDs light.
5) 24,000 bps (24.0). This LED is lit when the modem is connected at
24,000 bps. Note: if the modem falls back to 21.6K bps while in V.34
mode, both the 24.0 and 19.2 LEDs light.
6) 19,200 bps (19.2). This LED is lit when the modem is connected
at 19,200 bps.
7) 14,400 bps (14.4). This LED is lit when the modem is connected at
14,400 bps. Note: if the modem falls back to 12,000 bps while in V.32bis
mode, both the 14.4 and 96 LEDs light.
8) 9600 bps (96). This LED is lit when the modem is connected at
9600 bps.
9) 2400 bps (24). This LED is lit when the modem is connected at
2400 bps.
10) Off Hook (OH). This LED is lit when the phone line is "off hook".
This occurs when the modem is dialing, on-line, or answering a call.
This LED also flashes when the modem is pulse dialing in Command
mode.
11) Terminal Ready (TR). When the TR LED is lit, the modem is
permitted to answer an incoming call. When it goes off, a connected
modem will disconnect. The state of the TR LED matches that of the
DTR circuit on Pin 20 of the RS-232C/V.24 interface.
12) Error Correction (EC). This LED is lit when the modem is set for
V.42 error correction, and flashes on and off when data compression
is activated.
17
SERIES II INTELLIGENT DATA/FAX MODEMS
13) FAX (FX). This LED is lit when the modem is connected in FAX
mode.
14) 336+ (MD1640A) only: ERROR (ERR). When this LED is lit, either
the leased line is down and the modem is in dial backup mode, or else
the self-test has failed.
1.9 Controls on PC Board
The Series II Modem is designed on a single printed circuit (PC) board.
This board contains one 16-position DIP-Switch (numbered 1-16). The
DIP-Switches are accessible through a cut-out on the side of the
modem. There is also a knob which is used to adjust the speaker
volume. This knob is accessible through the modem's rear panel.
The sixteen DIP-Switches control various modem options or set default
values for Command Mode operation. There is a difference in how
several of the switches operate depending on whether you are in syn-
chronous or asynchronous mode. Refer to the switch label on the
bottom of the Modem for an exact list of the switch functions in
asynchronous and synchronous operation.
Chapter 9 of this manual also provides detailed instructions on
configuring all of the Modem's PC board options.
18
CHAPTER 2: Installation and Connection
2. Installation and Connection
2.1 Safety Warnings
1. Never install telephone wiring during a lightning storm.
2. Never install telephone jacks in wet locations unless the jack
is specifically designed for wet locations.
3. Never touch uninsulated telephone wires or terminals unless the
telephone line has been disconnected at the network interface.
4. Use caution when installing or modifying telephone lines.
5. Avoid using a telephone (other than a cordless type) during an
electrical storm. There may be a remote risk of electrical shock
from lightning.
6. Do not use the telephone to report a gas leak in the vicinity
of the leak.
19
SERIES II INTELLIGENT DATA/FAX MODEMS
2.2
Installation
The installation of the Series II Modem consists of making the physical
connections necessary to render the modem functional with your
computer. This includes making the proper serial, phone line, and
power connections. Refer to Figure 2-1 below for the Series II Modem
336 (MD1641A) or to Figure 2-2 on the next page for the Series II
Modem 336+ (MD1640A). Following the installation instructions are
some preliminary aspects of issuing AT commands and the Modem's
"Originating/Answering" capabilities.The installation process involves:
1. Verify the settings of DIP switches #5 (Originate vs. Answer mode)
and #10 (Lease Line vs. Dial-Up operation). See Chapter 9.
2. Attach the Series II Modem to a dialup phone line and/or a 2-wire
leased line using the included RJ11 telephone cords. For the 336
(MD1641A) model, run a cord from the LINE jack to the dialup
20
CHAPTER 2: Installation and Connection
wall jack or the leased-line wall jack or terminal (refer to Figure 2-1
below). For the 336+ (MD1640A) model, run a cord from the
PSTN jack to the dialup wall jack if you’re connecting to a dialup
line; run a cord from the LEASE jack to the 2- or 4-wire leased-line
wall jack or terminal if you’re connecting to a leased line (refer to
Figure 2-2 on the next page). 336+ (MD1640A) models only: For four-
wire lines, the modem uses pins 1 and 6 to transmit and pins 2 and
5 to receive.
PHONE
LINE
INTERFACE
ON
OFF
VOLUME
POWER
Figure 2-1. Series II Modem 336 (MD1641A) Connections
PHONE
PSTN
LEASE
INTERFACE
ON
OFF
VOLUME
POWER
Figure 2-2. Series II Modem 336+ (MD1640A) Connections
21
SERIES II INTELLIGENT DATA/FAX MODEMS
2. Attach your Modem to your PC or terminal with an RS-232
(or V.24) cable.
3. Connect telephone set to phone jack (if desired).
4. Attach your Modem to the AC Power transformer and plug t
he AC connector into a live AC outlet.
5. Turn on power by flipping the "ON/OFF" switch at the left rear
of the Modem to the "ON" position.
6. Assuming you have already chosen Dial-Up mode (DIP Switch #10
in the UP/OPEN position) or Leased Line mode (DIP-Switch #10
in the DOWN/CLOSED position, assign your modem to either
“originate” or “answer” mode. It doesn’t matter which mode you
select — just give the modem you’re connecting to the opposite
setting. For example, if you place DIP-Switch #5 UP, that modem
will be the answering modem. Then you should place DIP-Switch
#5 DOWN on the other modem so that it will be the originating
modem. Again, it doesn’t matter which is which, as long as the local
and remote modems have opposite settings.
7. Verify transmit dBm levels. The transmit level for dial-up lines is -
11dBm. The transmit level for leased lines is -9 dBm and may be
set alternately to -15 dBm with DIP-Switch #3.
8. Verify remote modem's current configuration settings with your
Series II Modem in terms of data compression, error correction,
transmission rate, etc. (per Chapter 5, Section 5.7.12, ATL5 and
ATL7 Commands).
9. Make sure modem and computer/terminal serial port baud rates
are adjusted. (Note that several programs can check this for you.
If you have MS-DOS 5.0 or higher, a program called MSD.EXE
(Microsoft Diagnostics) is in your DOS directory. Typing MSD at
the DOS prompt brings up a screen that provides a variety of
information about your computer. Select COM ports and it lists
information about your com port, e.g., UART Type, Address, and
IRQ to name a few. Once you know your serial port's UART type,
you can set your communications's software appropriately.)
10. Verify self-test results (Section 2.2).
11. Proceed to Chapter 3 of this manual, or to your data communica-
tions software manual.
22
CHAPTER 2: Installation and Connection
Note: Appendix A lists some basic and specific troubleshooting
actions to take if your Modem is not operational.
2.3 IsYour Series II Modem Ready for Use?
As soon as you connected power to the modem, it performed a
diagnostic self-test. The speed indicators flashed in sequence for
approximately four seconds, then the 28.8 indicator is lit. The TR
indicator should be lit as well. The SD, RD, CD, and OH indicators
should remain off at this time. If not, check that the transformer is
solidly connected and that your AC outlet is live.
If you’re an experienced modem user, you may simply want to check
your modem’s settings for data compression, error correction, and so
on. You may find that you can get moving quite quickly if you just issue
an ATL5, ATL6 and an ATL7 command. These commands lists how
your modem is currently configured. If you come across a setting you’re
unsure of, refer to Chapters 5 and 6 of this manual for AT command
and S-Register explanations and defaults.
If you’re a novice, please continue to the next sections of this chapter.
23
SERIES II INTELLIGENT DATA/FAX MODEMS
2.4 OperatingYour Series II Modem
You control your Series II Modem by issuing AT commands, setting
S-Registers, and setting DIP-Switches. You can easily change the settings
of your DIP-Switches, as they are located on the right side of your
Modem’s chassis. Right now your Modem is set up for the most typical
user application, that is, as a traditional modem set to make a dial-up
call to a remote installation where the call is answered automatically;
therefore, you shouldn’t need to change the DIP-Switches. (If however,
you know that your application does not follow this profile, please refer
to Chapter 9 of this manual for full details on DIP-Switch settings.)
While you may operate your Series II Modem manually, it is more
likely that you will use your data communications software to either:
•
enter “terminal” mode, where you can “speak most directly” to
the modem by issuing AT commands, or to
•
launch a datacomm session through a set of modem configurations
which you select and then associate with a target telephone
number. Once you have created, saved, and named this set of
information according to your connection needs and your
datacomm software’s conventions, the software then simplifies
your dialing because you needn’t re-configure your modem, nor
run the risk of mistakenly keying-in incorrect information.
Either way, you need to understand that an AT command is the method
by which your modem is controlled, and must therefore prefix nearly all
commands. AT stands for attention, and alerts the modem that a com-
mand follows. You may enter these commands with either upper- or
lowercase characters. Entering AT automatically sets the modem’s serial
baud rate to match your computer’s and also sets the modem’s parity. It
also clears the modem’s command buffer.
Once you’re in terminal mode, enter AT followed by <CR> to check
whether your modem is operational. If everything’s fine, your modem
will respond OK. (If your Modem is a 336+ [MD1640A] model, refer to
Chapter 4 for additional details on Dialing, Automatic Answering, Dial
Back-Up and Automatic Leased Line Restoral.)
24
CHAPTER 2: Installation and Connection
2.4.1 Simple Operations
You can dial a number by using the ATD command and the phone
number of the modem with which you wish to connect, e.g.,
ATD6127853500. Your modem will dial the number, and hear a
“scrambling” noise as the modem negotiates the kind of connection it
can make, and once the modems have settled on a common
connection, you will receive a connect message on your computer’s
video display. As the modem dials and connects, you may notice
changes across its front LED panel: the OH (Off Hook) LED lights to let
you know the modem is operating as if you had picked up the handset
to a phone. The CD (Carrier Detect) LED lights to let you know the
modem has detected a device it can connect to. A speed LED lights to
let you know at which speed the connection has been made.
To hang up a call, enter +++ATH<CR>. Your modem will return on
hook, just as if you had returned a phone’s handset to its cradle. Notice
also that the OH, CD and speed LED’s are no longer lit. Your video now
displays OK, signifying that your modem is ready for your next
command.
2.5 The Answer/Originate - Voice/Data Toggle Switch
Located on the front of the modem is a Voice/Data "toggle" switch with
Originate/Answer capabilities. This switch enables the modem to auto-
matically dial a phone number stored in the N1 location of memory
whenever this switch is toggled. (Note that you must first enter
AT$VD1&W0<CR>. This command string enables Voice/Data dialing
when the Voice/Data toggle switch is activated.)
If you are "manually" dialing with an attached telephone device (and
not with your keyboard), your Modem originates when this switch is
toggled to the corresponding position (DOWN); and if you are
"manually" answering (modem is not configured to automatically
answer via S-Register S0 setup), the Modem answers when this switch
is toggled to the corresponding position (UP).
25
SERIES II INTELLIGENT DATA/FAX MODEMS
3. Software Configuration
3.1 Introduction
Since your communications software configuration is affected by the
capabilities of your computer, this chapter begins with a discussion of
the limitations of some serial ports and how to identify them. It then
discusses communications configuration in general and recommends
settings specifically for the Series II Modem.
3.2 Serial Port Limitations
When you configure your software, you need to consider how the
hardware on both ends of the connection will affect the connection.
Some serial ports, particularly those in older PC-compatible computers,
may limit the performance of the Series II Modem. You should know if
yours is one of them.
The limiting factor is an integrated circuit called a Universal Asyn-
chronous Receiver/Transmitter, or UART. All data from your modem
flows through it. The UARTs typically used in PC-compatible computers
are types 8250, 8250A, 16450, and 16550AFN. The 8250 is unreliable
above 9,600 bps, and the 8250A and 16450 are unreliable above 19,200
bps. If the modem sends data to the UARTs above those speeds, the
UARTs may not be able to process the data fast enough to keep from
losing some of it. The 16550AFN, however, can safely handle data to
115,200 bps.
When a modem communicates with V.42bis 4-to-1 compression en-
abled, it sends up to four times as much uncompressed data to the serial
port as it receives compressed over the telephone line. Therefore, a
modem communicating at 14,400 bps may require a serial port that can
reliably transfer data at four times 14,400 bps, or 57,600 bps; at 19,200
bps it may require one that works reliably up to four times 19,200 bps,
or 76,800 bps; and at 28,800 and 33,600 bps it may require one that
works reliably up to a maximum of 115,200 bps. If your serial port
cannot handle these speeds, we recommend that you replace your
present serial card with one that has a 16550AFN UART or equivalent.
26
CHAPTER 3: Software Configuration
®
Macintosh computers do not use UARTs. The Macintosh SE through
®
IIfx models use a Zilog Z8530 chip called a Serial Communications
Controller, or SCC, that has a maximum speed of 57,600 bps. This
speed can be compromised by other serial communications, including
®
printer transmissions and Appletalk , the networking software that
allows Macintoshes to share files. When Appletalk is active it controls all
serial communications on the Macintosh. Because it gives priority to
network communications, it may lose modem data at higher
transmission speeds. Therefore, when Appletalk is active you risk losing
data on serial port communications over 2400 bps, though most users
can work up to 9600 bps without problems. Other activities that could
cause the serial driver to drop bits at high speeds include the floppy disk
driver formatting a disk, the CPU paging in or out in virtual memory
®
mode, and the Mac IIci or IIsi running the on-board video in 8-bit
mode. Therefore, for maximum communications speed on the
Macintosh, we recommend as few concurrent activities as possible. To
use V.42bis compression at 19,200 bps or faster, we recommend that you
install a high speed serial port card. Newer Macintosh computers, such
as the Quadra and Centris models, support serial port speeds up to
115,200 bps.
3.2.1 How CanYou IdentifyYour UART Type?
If you have MS-DOS 6.0 or later, you can find your UART type from
a diagnostic program called MSD. To use it, type MSD at the DOS
prompt. After the opening screen, select COM Ports.... The last line of
the report tells you what type UART you have for each COM port. MSD
does not distinguish between the 8250 and the 8250A. However, if you
have an IBM AT or newer computer, you likely have an 8250A or 16450
UART installed, both of which are reliable to 19,200 bps. If you would
like more detailed information about your UART than MSD can
provide, you can download shareware UART identification programs
from the World Wide Web, from the IBM Communications Forum on
®
CompuServe , or from a local BBS.
27
SERIES II INTELLIGENT DATA/FAX MODEMS
3.2.2 The 16550 UART and Windows 3.1
Windows 3.1 may cause a loss of data when communicating at high
speed, even with a 16550 UART installed. Because Windows is multitask-
ing—it switches between several programs running at the same time—
it can make the serial port wait briefly while Windows performs other
tasks. Meanwhile, incoming data can be lost. The older 8250A and
16450 UARTs can store data in a one-byte first in-first out (FIFO) buffer
(a memory area in the UART in which the first bit in is the first out),
but once the buffer is full, the data is lost. The 16550 has a 16-byte FIFO
buffer, which accounts for much of its high speed. However, in Windows
3.1, the 16550’s FIFO buffer is disabled by default. To enable the buffer,
use Notepad to open the SYSTEM.INI file in your Windows directory,
and add the following line to the [386Enh] section:
COMnFIFO=1
where n is the number of the COM port the 16550 is installed on.
For example, if the 16550 is installed on COM2, the line should be:
COM2FIFO=1
After you save SYSTEM.INI you must restart Windows for the change
to take effect.
However, there is another problem when the FIFO buffer is enabled:
Windows cannot recognize the COM port because of a bug in the
Windows 3.1 serial port driver, COMM.DRV. The only way around this
problem is to replace the COMM.DRV file in the WINDOWS\SYSTEM
directory with another driver. Several drivers are available commercially,
on the World Wide Web, or on BBSes that will solve this problem.
A freeware driver called CyberCom is available as CYBERC.ZIP on
CompuServe in the IBM Communications Forum, Library 0. CyberCom
will enable Windows communications at speeds up to 115,200 bps if you
have a 16550 UART installed.
28
CHAPTER 3: Software Configuration
3.3 ConfiguringYour Software
Communications software must be configured to work with your mo-
dem, your computer, and the remote system it is calling. Fortunately,
most communications programs make the process easy by providing a
default initialization string for your modem as well as defaults for most
of the other required parameters.
3.3.1 Configuring Software forYour Modem
Because remote computers may have different connection re-
quirements such as speed, number of bits, parity, log-on sequences, etc.,
communications software is typically configured by sessions, each session
having a unique configuration for a given connection (e.g., to the
Internet, to a BBS, or to a commercial on-line service). Most communi-
cations programs, however, have a separate modem configuration menu
because modem configurations rarely change from session to session.
The most important configuration is the modem initialization string.
This is a sequence of commands the software uses to configure the
modem when the communications software is loaded or when a session
begins. Always begin the initialization string with the ATtention
command AT, then follow it with the modem reset command, &F.
Issuing a reset command before other commands ensures that you are
starting with a known state.
The rest of the commands in the initialization string depend on the
capabilities of the modem and what you want it to do. Some older
communications programs require you to create the initialization string
by yourself. Most modern communications programs, however, provide
you with a ready-made initialization string that is automatically selected
when you choose your modem model from a list. It is a poor idea to use
an initialization string intended for another modem, especially one
from another manufacturer, because modem capabilities and command
implementations vary from modem to modem. However, if your Series
II Modem does not appear on a modem list, you may use any initializ-
ation string labeled “MultiModemII” that might appear in the list.
29
SERIES II INTELLIGENT DATA/FAX MODEMS
3.4 PC Initialization Strings
We recommend the following initialization string for a Series II Modem
connected to a PC-compatible computer when sharing a line with a
telephone:
AT &F X4 S0=0 ^M
This string resets the Modem to the factory default settings, selects ex-
tended result codes with NO DIAL TONE and BUSY, and turns off auto-
answer. ^M must end every string sent to the modem from software.
It is the ASCII code for the RETURN key on most keyboards, and the
default code for the carriage return character in the Modem and most
communications programs. The carriage return character is defined in
the Modem in S-register S3; if you change it, you must also change the
carriage return character code used in your communications software.
If you send a command directly to the modem in terminal mode rather
than indirectly through communications software, you must end the
command string by pressing the RETURN key (<CR>) instead of adding
^M to the string.
The following initialization string is for a Modem on a telephone line
that functions solely as a DATA LINE:
AT &F X4 S0= 2 ^M
3.4.1 Changing Default Parameters
By default, the Series II Modem will answer after the first ring and try to
communicate with a modem on the other end of the line. If you have
one telephone line for voice, fax, and modem communications, the
Modem may attempt to answer all incoming calls, voice as well as data.
To change auto-answer to default off, open your communications
program and type the following string in the terminal window:
AT &F S0=0 &F9 &W0 <CR>
30
CHAPTER 3: Software Configuration
This string selects the factory default parameters, then turns auto-
answer off and stores that setting, along with all other current para-
meters, in nonvolatile memory. The &F9 command causes the modem
to load the values from nonvolatile memory the next time it receives
the &F command. You will use the same initialization string as before:
AT &F X4 ^M
But now the Modem will load the values stored in nonvolatile memory
when you turn on the modem and when you issue the ATZ or AT&F
reset commands.
Note: Because it clears the command buffer, you should not use ATZ
in an initialization string.
3.4.2 Other Parameters
The default values for the other parameters in modem configuration
menus rarely need changing. They typically include the dialing prefix
(ATDT for touch-tone service and ATDP for rotary service), the dialing
suffix (^M), the hang-up string (+++ATH0^M), and response messages
(RING, NO CARRIER, BUSY, etc.). Communications software with a host
mode might also include an auto-answer string (ATS0=1^M).
3.5 Macintosh Initialization
Macintosh computers cannot use RTS/CTS hardware flow control
without a serial cable wired for hardware control. The Macintosh 128
and 512 models cannot use RTS/CTS flow control at all. For those
Macintoshes turn off the default RTS/CTS hardware flow control, turn
on XON/XOFF flow control and pacing, and ignore DTR:
AT &F X4 &E5 &E13 &D0 ^M
For hardware flow control, use the following initialization string:
AT &F X4 &E13 &D0 ^M
Add S0=0 to both strings to disable auto-answer if the Series II Modem
is on a voice line.
31
Chapter 3: Software Configuration
You can store the initialization string in nonvolatile memory. With your
communications software open and connected to the modem’s COM
port, type the initialization string in the terminal window, substituting a
carriage return for ^M. To store the string, enter
AT &F9 &W0 <CR>
Now you can initialize your modem with the following simple string:
AT Z ^M
3.6 Configuring Software forYour Computer
You must configure your communications software to match your com-
puter’s configuration. If the Series II Modem is connected to the COM2
serial port, you must tell the software you are using COM2. Another
important parameter is the serial port baud rate. This is the speed at
which your modem communicates with your computer, not the speed at
which your modem communicates with another modem. When V.42bis
data compression is enabled, you must have a serial port baud rate four
times the transmission speed of the modem to fully optimize
compression. So if your UART is fast enough, you should set the serial
port baud rate to a minimum of four times the top speed of your
modem.
If you have an 8250 UART, your most reliable serial port speed will be
9600 bps; if you have an 8250A or a 16450 UART, try 19,200 bps; if you
have a 16550 UART or equivalent, a serial port setting of 115,200 bps
can be set reliably.
3.6.1 Configuring Software for the Remote System
You must meet the requirements of the remote system for successful
communications. Though the Series II Modem can automatically match
the speed of the other modem, you must specify parameters such as
type of flow control, break length, number of data bits, number of stop
bits, and parity. If you set these parameters incorrectly with the remote
system, gibberish will appear on your screen.
32
User Guide for Series II Modems
3.6.2 Terminal Emulation
If you are accessing the remote computer as if from an on-site terminal,
the keyboard codes used by your computer may not match the ones
used by the remote computer. To be compatible with the remote com-
puter, your software must be able to substitute the appropriate codes in
what is known as terminal emulation. Most communications programs can
emulate the most common mainframe terminals, including the DEC
VT100, VT102, and VT52 terminals, and the basic TTY mode. If in
doubt about which to choose for a Telnet session, a BBS connection,
etc., try ANSI or VT100 first.
3.6.3 File Transfer Protocols
When you upload or download files with your Series II Modem through
a browser, it will transparently use the appropriate protocol (usually
http or ftp). When you are uploading or downloading through a
terminal emulator, however, the host computer will ask which file
transfer protocol you want to use. Most communications programs allow
you to choose a default protocol. Your software’s documentation should
list the ones it can use (not all communications programs support all
protocols). Zmodem is the recommended protocol for most transfers.
3.7 When to Disable Data Compression
If your serial port cannot keep up because it has an older UART, you
may lose data when using data compression. Also, the speed advantage
hardware compression gives you is entirely dependent on how much
the data being transmitted can be compressed. If the data is already in
compressed form—a .ZIP or a .SIT file, for example—trying to com-
press it more will actually slow the transmission slightly compared to
transmitting the same file with compression disabled. This effect will be
most noticeable if your modem negotiates MNP 5 compression with the
other modem. V.42bis will not try to further compress a compressed file,
but MNP 5 will.
33
SERIES II INTELLIGENT DATA/FAX MODEMS
The command to disable compression is AT &E14 <CR>. If you have
an older UART or if you use your modem mostly for downloading long,
compressed files from BBSs, you may want to include the &E14
command in your initialization string as follows:
AT &F S0=0 X4 &E14 ^M
As a general rule, you should try to transmit files in already-compressed
form rather than relying on V.42bis hardware compression. Because
software compression is more efficient than hardware compression, you
will have a higher throughput with the former. Of course, this efficiency
does not include the time spent compressing and decompressing .ZIP
or .SIT files, but it will save on phone bills. And hardware compression
will still be there for those occasions when it is inconvenient to
compress a file with software. Note also that when you download files
with compression disabled, you can use a slower serial port if you have
an older UART.
3.7.1 Disabling Error Correction
By default, the Series II Modem is set to auto-reliable mode. In this
mode the Modem determines during the handshake whether the other
modem is using V.42 error correction. If it is, the Modem then switches
itself to reliable mode and enables error correction. If it is not, the
Modem remains in non-error correction mode.
Normally, we recommend that you leave the Modem set to auto-reliable
mode (&E1). However, you may encounter some circumstances in
which the Modem will work better with error correction turned off. For
example, it has been reported that on CompuServe error correction will
slow file transfers at modem speeds of 9600 bps and under. If this is a
problem for you, you can turn off error correction with the command
AT &E0, or you can include the command in your initialization string as
follows:
AT &F S0=0 X4 &E0 ^M
34
CHAPTER 4: Manual Dial and Automatic Answer
4. Manual Dial and Automatic Answer
4.1 Introduction
We’ll assume that yours is the very common application, where you are
using a Series II Modem to dial up a remote computer. The Series II
Modem has been factory preset for originating a call to a compatible
33,600 bps modem (also set up for hardware flow control, V.42 error
correction, V.42bis data compression and CTS/RTS operation). If the
answering modem is not set up similarly, the Modem automatically
adjusts to the appropriate protocol.
4.2 Dialing/On-Line/Answering
There are several basic steps for “originating” and “answering” in data
communication mode:
1.
2.
3.
4.
Load communication software
Dial
Establish On-Line connection
Terminate Call
A simple way to dial is from the keyboard of your computer or terminal.
You enter a command on the keyboard to tell the Series II Modem to
dial.
If you use a sophisticated communications software package, the
software tells you to enter phone numbers and other information. If
this is the case, the software, and not you, gives the dialing commands
to the modem. All of the commands, option registers and intelligent
features of the Series II Modem are taken care of by the software.
If you are giving commands directly to your modem (and not through
your software), each command must begin with AT (ATtention
Characters). AT characters may be entered in upper or lower case.
35
SERIES II INTELLIGENT DATA/FAX MODEMS
Entering AT automatically sets the modem’s speed to match the speed
of the computer or terminal, and also sets the modem’s parity.
The AT characters alert the modem that a command follows. The AT
Command can also be used to clear the command buffer, by simply
typing AT and hitting RETURN.
The letter D in a command causes the modem to dial the numbers
immediately following it (e.g., ATD7247465500). You have a choice
of either pulse (ATDP) or tone (ATDT) dialing methods.
The Modem responds with “CONNECT” on your video display after the
number is dialed and a connection signal is detected (since the Modem
defaults to Enhanced V.34/V.42/V.42bis, the actual response is
"CONNECT LAPM COMPRESSED”), if the Series II Modem “connects”
with a similar modem (see section 5.3 Result Code Summary). The
modem is now in “On-Line” mode, and is ready to communicate with a
host site.
If no connection signal is detected within 45 seconds (this time period
can be adjusted by S-Register S7), the Modem goes On Hook/hangs up
and returns to Command mode. At this point, your video displays “NO
CARRIER”.
Enter +++ATH to Hang Up On-Line (bring modem on-hook), and
terminate the modem's On-Line mode. At this point, your video
displays “OK”.
In addition to the call originating capabilities, the Modem can also
automatically answer incoming calls. You need not be present. You can,
however, control the situation by configuring the modem to either
answer or not to answer, or to answer after a specified number of rings.
This is done by setting the value of S-Register S0 (modem defaults to
automatically answer an incoming call after one ring). Refer to
Chapter 6 for S-Register details.
36
CHAPTER 4: Manual Dial and Automatic Answer
4.3 Automatic Leased Line Restoral Operation
(336+ Only)
When the Series II Modem 336+ (MD1640A) is in Dial Backup mode, it
periodically checks the leased line to see if it's operational and tries to
restore the leased line if possible. S-Register S18 determines how often
restoral attempts occur. The default for S18 is 30 minutes, and can be
set in one minute increments from 10 to 255 minutes. Setting the
restoral attempts under 10 minutes causes excessive breaks in the
dial-up operation.
Note: Both local and remote modems must have S-Register S18 set
identically. Refer to Chapter 6 for more information on S-Register S18.
4.4 Manual Dial Backup Call Termination (336+ Only)
With your Series II Modem 336+ (MD1640A) in leased line mode (DIP-
Switch #10 in the DOWN position) and with dial backup operation in
process, there are two ways to manually terminate the dial backup call
(other than automatic leased line restoral). In each case, you will try to
establish the leased line connection because it is back in operating
condition. The methods of dial backup call termination are:
1) Manual Control. The "Voice/Data" switch can be used to change
from a dial back line to leased line by toggling down once. When
that is done, the Modem tries the leased line connection, and, if it
is good, the modem disconnects the dial back call and establishes
a leased line connection.
2) DTR Control. If DTR (Data Terminal Ready) is turned off for 50
milliseconds or more, a disconnect occurs. This is probably the
most common method used by computer systems at the automatic
answer end of the line to cause the answering modem to
disconnect after toggling off procedures.
4.5 Dial Backup and Leased Line Restoral (336+ Only)
The dialing associated with the Series II Modem 336+ (MD1640A) when
it's in "leased line with dial-back" mode, involves placing a call from the
originating modem due to a leased line failure.
37
SERIES II INTELLIGENT DATA/FAX MODEMS
After a preset period of time (determined by S-Register S18), the
modem automatically tries to restore the leased line.
The parameters used to determine if a leased line is down (so automatic
dial back can occur), is based on the Series II Modem doing a “retrain”
on the leased line due to an error condition in the transmission. An
error condition is defined as a "hit" on the line (the Carrier gets
interrupted).
The retrain is a "handshake" procedure between the modems to
establish the Carrier again. If the retrain fails, both modems (originate
and answer modems) start their Dial-back timers. The time is
determined by S-Register S19 settings. The S19 default setting is one
minute. During that minute, the originate modem tries to establish the
leased line link. If the leased line is established during that time, the
timer is cleared and everything is back to normal. If the timer expires,
the modems goes to dial-back mode.
The purpose of the timer for the Answer modem is to determine when
it accepts a dial-up call. When both timers have expired and the leased
line has not been established, the dial-back procedure starts. The
number dialed is the one stored in location N9 of the originate
modem's phone number memory. In the preparation for proper
dial-back operation, enter the proper number in the N9 location using
the commands detailed in Chapter 5. Keep in mind that the number
also can be dialed in V.25bis Command mode.
38
CHAPTER 4: Manual Dial and Automatic Answer
4.6 Dial-Up Operation (336+ Only)
When your Series II Modem 336+ (MD1640A) is used as a dial-up
modem (DIP-Switch #10 in the UP position), it can both originate and
answer calls. To originate calls, you use the automatic dialing capability
of the Modem's Command mode.
To do this, use the computer or terminal keyboard to enter a few
command letters, followed by the phone number you wish to dial. If you
have a computer with sophisticated communications software, you may
end up talking back and forth with the software, and the software will
take care of talking to the modem.
It is still possible, however, to dial your data calls using a telephone set.
There are few reasons why you would want to do this, but if you have a
need to use the telephone set to dial, we explain how in the next
section. We will delay our coverage of Command Mode autodialing,
and all other Command Mode features, until Chapter 5.
4.7 Manual Call Origination
You can use the Series II Modem to both originate and answer calls.
To originate calls in Asynchronous mode, you will most likely use the
Modem's Command mode, and give the modem automatic dialing
commands (we will delay our discussion of the Command mode until
Chapter 5). When using your modem in Synchronous mode, the
Command mode is disabled, so you must automatically dial your calls
with a telephone set. To use manual dialing, you first connect an
ordinary telephone set (either touch tone or rotary dial) to the
modem's PHONE Jack, if you have not already done so. Next, set the
speed selection, (DIP-Switches #13 and #14), to the speed at which you
wish to communicate. These DIP-Switches are located on the side of the
modem. (Refer to Chapter 9 for DIP-Switch settings.) Your computer or
terminal may be set for up to 115,200 bps.
When your telephone set is connected, you can use it to dial the
modem you wish to call. Simply dial the number, and then listen to the
dialed modem's answer tone. When you hear it, press the Voice/Data
switch on the front of the modem down (to the Originate position). You
don't have to hold it down. Just "toggle it" (press it once and let it go).
39
SERIES II INTELLIGENT DATA/FAX MODEMS
Once you press the switch, the tone you hear should change to another
pitch, or change into a rough-sounding scrambled noise. You then
replace the telephone handset in its cradle, and your data
communications begins.
Note that the Series II Modem may call manually via the keyboard
command ATD, or by pressing the Voice/Data switch on the modem's
front panel downward. To force the Modem to automatically answer
calls, either type ATA, or press the Voice/Data switch on the modem's
front panel upward.
4.8 Automatic Answering
The Series II Modem can be used as an automatic answering modem.
No special modifications or settings are required other than making
sure that the Auto-Answer select switch is set to Auto-answer enabled
(DIP-Switch #5 UP).
The Modem, when in its idle state, is set for Originate mode frequencies.
An incoming ring signal automatically switches the modem into Answer
mode.
You can program the modem to answer a call after a certain number of
rings using S-Register S0 (see Chapter 6). Refer to Section 4.10 for the
handshaking procedures used by the Modem when in automatic answer
mode.
In many originate-only applications, you may wish to disable the
automatic answer capability of the modem. If a telephone set is
connected to the modem, you may wish to receive incoming calls in
a voice mode for normal voice conversation. If auto-answer is not
disabled, all incoming calls are answered by the modem, preventing
voice communications. To disable automatic answer, place DIP-Switch
#5 to the DOWN (Disable Auto Answer) position (refer to Chapter 9).
Another way to disable automatic answer is to use S-Register S0 to
configure the modem to answer on the nth ring, where n equals zero
(0). Another alternative is to have the modem answer after five or six
rings, which gives you time to answer it manually if you wish. (See
Chapter 6 for S-Register information.)
40
CHAPTER 4: Manual Dial and Automatic Answer
4.9 Manual Answering
We have shown that the Series II Modem can automatically answer
incoming calls. The Modem can also answer manually, under your
control. The most typical application involves you and another person,
who, after carrying on a voice conversation, want to convert to data
communications between your modems without having to hang up
and dial again.
The problem here is that both modems are in originate mode. For two
modems to communicate, one of them must be in originate mode and
the other must be in answer mode. The solution here is to force either
one of the two modems to Answer mode, and the other to Originate
mode.
The Modem can be forced into either Answer mode or Originate mode
by using the Voice/Data switch on the front of the modem.
In our example, let's say that you and your friend Bill have just had a
voice conversation. Both of you have your telephones connected to your
Series II Modems, and your modems are connected to computers or
terminals. Set the speed switches to the proper speed on both modems.
To switch to Data mode from Voice mode, you would switch the
Voice/Data switch Down (to the Originate position), and Bill would
switch his up to Answer. This switches your modem to the originate on-
line mode, and Bill's to the Answer on-line mode. You would both then
hang up your telephone handsets, and continue the conversation via
your keyboards.
4.10 Handshaking Details
This section briefly explains what happens between two modems in a
normal call. We are assuming that there are Series II Modems at both
the originating and at the answering end of the telephone line. (If
other brands of modems are used with our modems, they will still
communicate, but each manufacturer tends to use slightly different
delay timings and sequences, and many of the brands vary in their
LED designations.)
41
SERIES II INTELLIGENT DATA/FAX MODEMS
When a call is dialed from the originating modem, the called modem
responds to the ringing by switching into Answer mode and by turning
on its RI (Ring Indicator, RS-232C/V.24 Pin 22) signal as the rings are
detected. (The Modem-MAC does not use DTR.)
Note that in order for the called modem to be able to answer the call, it
must have a high DTR (Data Terminal Ready) signal. This signal comes
from the computer or terminal to which it is attached, on RS232C Pin 20.
When the called modem answers the call, its OH (Off Hook) circuit
comes on and the ringing stops. Two seconds after the call is answered,
the called modem begins transmitting its answerback tone.
The originating modem, which has been off hook and waiting for the
answerback tone, turns on its transmitter when it hears the tone. Then
after a one second delay, the orignating modem's CD (Carrier Detect)
comes on.
The called modem then responds to the originating modem by turning
on its CD (Carrier Detect) signal, and the handshaking is completed.
Note: With the modem in Reliable or Auto-Reliable mode, some
additional handshaking takes place. This is explained in Section 5.4.8.
4.11 Call Termination
There are a number of ways to terminate a call, or simply stated, hang
up. They are:
1) Command Mode Control. To terminate a call by Command
Mode, enter +++ATH then RETURN; or, send a BREAK signal
followed by ATH and a RETURN.
2) DTR Control. If DTR (Data Terminal Ready) is turned off for 50
milliseconds or more, a disconnect occurs. This is probably the
most common method used by computer systems at the automatic
answer end of the line to cause the answering modem to
disconnect after logging off procedures.
3) Loss of Carrier. After a data connection is established, the
modem disconnects if a loss of carrier occurs for 700 milliseconds
(0.7 seconds) or more. Note that one cause of carrier loss would be
if one of the modems disconnect normally.
42
CHAPTER 4: Manual Dial and Automatic Answer
4) Abort Timer.
Answer Mode: When OH (Off Hook) comes on, the called modem
starts a forty-five-second timer and waits for a carrier signal from
the originating modem. If carrier is not detected within this period,
the modem disconnects (hangs up) and is ready for another call.
Originate Mode: The abort timer functions the same as in answer
mode, except that the timer begins after the modem has
completed dialing, instead of when it first goes off hook. It is
possible to change this forty-five second wait period to any other
value (from 0 seconds up to 255 seconds), or to disable the timer
completely by re-configuring S-Register S7 (see Chapter 6.)
5) Inactivity Timer. Causes the modem to disconnect if no data is
transmitted or received for a specified time. The timer is restored
any time a character is passed through the serial port in either a
send or receive state. This timer runs in both normal or reliable
connections and is controlled by S-Register S30. The Inactivity
Timer can be disabled by setting S30 to 0, which is the factory
default setting.
43
SERIES II INTELLIGENT DATA/FAX MODEMS
5. Command Mode
5.1 Introduction
AT commands are the means by which you, and your communications
software, are able to communicate with and configure your modem.
They enable you to establish, read, and modify parameters in addition
to dialing. The following provides both a summary and a detailed
explanation of the AT commands recognized by the Series II Modem.
5.1.1 AT Command Editing
The BACKSPACE key on your keyboard can be used to edit characters
in the AT command line. An AT command is not executed until the
RETURN key is pressed. The BACKSPACE key erases the previous
character for reentering.
The BACKSPACE key does not erase the AT characters once they are
entered. If your keyboard has no BACKSPACE key, CTRL-H does the
same thing. The character recognized by the modem as BACKSPACE
may be changed to any other ASCII character with S-Register S5.
If you wish to cancel an entire command that has been entered but not
yet executed, enter CTRL-X. This also clears the command buffer. The
effect is the same as backspacing to cancel the entire command, only
quicker.
Characters entered in a command are stored in the modem's Com-
mand Buffer (memory) until executed by hitting RETURN. The
Command Buffer's capacity is sixty characters. The Attention Characters
AT do not count in the sixty allowed Command characters. Spaces,
which may be used for increased display readability, may be used when
entering a command, but are not stored in the Command Buffer and
are not counted in the sixty allowed characters. Hyphens, parentheses,
etc. are not allowed.
If the sixty character limit is exceeded or if invalid characters are
entered, the Command Buffer automatically erases, and an ERROR
message appears. You would then re-enter your command within the
sixty-character maximum, using only the allowed characters.
44
CHAPTER 5: Command Mode
5.1.2 Functional Modes
The Series II Modem can be in one of two functional states (see Figure
5-1). These are "Command mode" and "On-line mode". (There is also an in-
between state, "Wait-for-Carrier", where the modem is out of Command
mode but not yet really On-Line.
When the modem is initially powered up, it is in Command mode and
is ready to accept commands from your keyboard or software. The
Modem enters On-line mode after dialing, making a connection with
another modem, and then detecting a valid carrier signal. If no carrier
is detected within a certain time frame, the modem abandons the call
and re-enters Command mode.
Once on line, the modem exits On-line mode if one of two conditions is
met. If the carrier is lost or intentionally dropped, the modem hangs up
and re-enters Command mode. Also, if the Modem recognizes the
Escape sequence for which it is configured (i.e., either the Escape
characters in the serial data stream, the Remote Escape characters in
the modulated data stream, or the Break signal), the Modem will exit
On-line mode, retain the datacomm link, and enter Command mode.
You can force the Series II Modem into On-line mode without dialing
by sending the ATD or ATA command to the modem.
45
SERIES II INTELLIGENT DATA/FAX MODEMS
+++AT
COMMAND
MODE
Dial (D or A)
HANG
UP
command, or
incoming
phone call
WAIT FOR
CARRIER
no carrier
detected
carrier detected
AT0
command
ON-LINE
MODE
carrier lost
Figure 5-1. Functional Modes
5.2 Summary of AT Commands
A wide variety of autodial operations and modem options can be con-
trolled when the Series II Modem is in Command Mode. Remember,
nearly all commands begin with AT.
These commands are organized into several functional groups. An al-
phabetical summary of commands is provided in Appendix D.
HOW TO
COMMANDS
DIAL
D Dial
A: or : Continuous Redial
$D
$VD
N
DTR Dialing
Voice/Data Dialing
Dial a Stored Number
MODIFY DIALING
PROCEDURES
P/T
&P
,
Y
W
Pulse/Tone Dialing
Set Pulse Dial Ratios
Automatic Pauses in dialing
Long Space Disconnect
Wait for New Dial Tone
46
CHAPTER 5: Command Mode
;
Return to Command Mode After Dial
Command
R
!
Reverse Mode of Operation
Flash On Hook
$
@
AT&T "Calling Card" Tones
Quiet Answer
MEMORIZE PHONE
NUMBERS
D...N
NN
L
Store Phone Numbers
Number Linking
List Numbers Stored in Memory
STORE MODEM
CONFIGURATIONS &W
AND DEFAULTS
&F
Load Factory Defaults
Store Configuration & S-Register
Parameters
Z
Reset Modem
$SP
#V
UNIX/"Spoofing”
336 (MD1641A) only: Enable/Disable
V.32terbo
&M
&X
Synchronous/Asynchronous Mode
Select
Synchronous Transmit Clock Select
CONFIGURE
COMMAND
RESPONSES
Q
Result Codes Enable/Disable
Response
&Q
E
V
Result Code Selection
Echo Command Characters
Result Code Terse/Verbose
Result Code...Basic/Extended/Call
Progress
X
CONDITION
PHONE LINE
AND MODEM
HARDWARE
&G
M
&T
#T
Guard Tones
Enable/Disable Monitor Speaker
Remote Digital Loop Signal
Enable/Disable Trellis Coded
Modulation
#F
$FC
Fallback When On-Line
336+ (MD1640A) only: Enable/Disable
Lowspeed Fast Connect
Cleardown at Disconnect
Auto-Speed Detect
&CD
#A
47
SERIES II INTELLIGENT DATA/FAX MODEMS
CONTROL RS232C &C
Carrier Detect Control
INTERFACE
&D
&R
&S
&RF
&SF
Data Terminal Ready Control
Clear To Send Control
Data Set Ready Control
CTS/RTS Control
DSR/CD Control
CONFIGURE
ERROR
CORRECTION
&E0
&E1
&E2
#L0
Normal Mode
Auto-Reliable Mode
Reliable Mode
Negotiate V.42 Mode During
Handshake
#L1
#L2
#L3
$A
MNP On/LAPM Off
LAPM On/MNP Off
Direct LAPM/Phase Out Handshake
Auto-Reliable Buffering
Enable/Disable Auto-Reliable
Fallback Character
$F
$R
$E
Retransmit Count
Error Correction at 300 bps
CONFIGURE
FLOW CONTROL
&E3
&E4
&E5
&E6
Flow Control Disabled
Hardware Flow Control
Xon/Xoff Modem-Initiated
Xon/Xoff Modem Responds/No Pass-
Through
&E7
Xon/Xoff Modem Responds/Pass-
Through Allowed
#X
Send Single/Multiple Xoff Characters
Enq/Ack Off
Enq/Ack On
Normal Mode Modem Flow Control
Off
&E8
&E9
&E10
&E11
Normal Mode Modem Flow Control
On
&E12
&E13
&BS
Computer-Initiated/Off
Computer-Initiated/On
Maximum Block Size
48
CHAPTER 5: Command Mode
$EB
336 (MD1641A) only: 10/11-Bit
Asynchronous Format
#P
Parity Selection
CONFIGURE DATA &E14
Data Compression Disabled
Data Compression Enabled
COMPRESSION
&E15
CONFIGURE SPEED $BA0 Speed Conversion On
CONVERSION
$BA1 Speed Conversion Off
$MB
Set modem speed (e.g., $MB33600)
$SB
Set serial port speed
(e.g., $SB115200)
EXECUTE
IMMEDIATE
ACTION
$H
I
I 9
L5
L6
L7
Help
Product Code Inquiry
Windows 95 Autodetect Inquiry
List Current Operating Parameters
List S-Register Values
List additional Configuration
Parameters
COMMANDS
L8
H
List On-Line Diagnostics
Off Hook
+++AT<CR>
Escape Sequence: Entering
Command Mode while On-Line
Escape Sequence Options...Entering
Command Mode while On-Line
Force Answer Mode
Exit Command Mode/Go Back On-
Line
%E
A
O
EXECUTE
LINE
%DF
Format Line Probe Display (Graph or
Table Format)
PROBE
COMMANDS
%DP
L9
Enable/Disable Reading Line Probe
Display of Signal Strength
Information
L10
L11
&RP
Display Signal to Noise Ratio (SNR)
Display of Noise Information
Initiates Retrain to Read Line Probe
Parameters
49
SERIES II INTELLIGENT DATA/FAX MODEMS
READ AND
ASSIGN
Sr?
Sr=
Read Current S-Register Value
Assign S-Register Value
S-REGISTER
VALUES
REMOTE
#CBN Passwords for Callback Phone #s
CONFIGURATION
& CALLBACK
SECURITY
#DB
#I
#RCBNxx
Callback Security Enable/Disable
Change LOGIN Password
Erase Password Linked with
Memory Location xx
#S
Change SETUP Password
TEST MODEM
U
&T
Self-Test Modem (Chapter 8)
Enable/Disable Digital Loopback
Signal
5.3 Result Codes
The Series II Modem Command mode provides you with several re-
sponses, or “Result Codes”, that can aid you in Command mode
operation. These Result Codes are displayed on your video monitor.
You can choose result codes that closely match those of the standard AT
command set, or choose enhanced function result codes that have been
used in Series II Modems (“Series II" responses). The &Q command
selects which result codes will be used.
You can choose to have these Result Codes displayed in either “verbose”
(full words) or “terse” (digits) format. This is controlled by the ATV0
(terse) or ATV1 (verbose) commands. The Series II Modem defaults to
verbose format.
AT&Q0 selects Series II responses with Reliable/LAPM/Compression
modifiers. The terse response code for CONNECT 2400 is 9. AT&Q1
selects Standard AT command set responses. The terse result code for
CONNECT 2400 is 10.
50
CHAPTER 5: Command Mode
The following tables define the result codes generated by the &Q
command (refer to Appendix G for Result Code Summary).
Table 5-1 &Q0 "Series II" Result Codes
TERSE
0
1
2
3
4
5*
6
7
VERBOSE
OK
CONNECT
RING
NO CARRIER
ERROR
CONNECT 1200
NO DIALTONE
BUSY
TERSE
11*
12*
13*
19*
21*
24*
26*
28*
VERBOSE
CONNECT 4800
CONNECT 9600
CONNECT 14400
CONNECT 19200
CONNECT 21600
CONNECT 24000
CONNECT 26400
CONNECT 28800
CONNECT 31200
CONNECT 33600
8
9*
NO ANSWER
CONNECT 2400
31*
33*
* With MNP error correction on, RELIABLE (or R) is added to these result
codes. With LAP-M error correction on, LAP-M (or L) is added to these result
codes. With data compression on, COMPRESSED (or C) is added. (Note these
"Extended" Result Codes are displayed when your modem is set up to do so with
an X1, X2, X3, or X4 command.)
Table 5-2 &Q1 “Standard AT” Result Codes
TERSE
VERBOSE
OK
CONNECT
RING
NO CARRIER
ERROR
CONNECT 1200
NO DIAL TONE
BUSY
TERSE
11
12
13
19
21
24
26
28
VERBOSE
0
1
2
3
4
5
6
7
8
10
CONNECT 4800
CONNECT 9600
CONNECT 14400
CONNECT 19200
CONNECT 21600
CONNECT 24000
CONNECT 26400
CONNECT 28800
CONNECT 31200
CONNECT 33600
NO ANSWER
CONNECT 2400
31
33
*Reliable/Compression modifiers are not displayed with Standard AT Result
Codes.
51
SERIES II INTELLIGENT DATA/FAX MODEMS
5.4 Dialing Commands
5.4.1 Dialing Action Commands
Dial Command D
The letter D in a command causes the Series II Modem to dial the
telephone number immediately following it. For example, if you enter
ATD5551212 and hit RETURN, the Modem dials the number 555-1212.
The D command is also used in conjunction with a telephone set for
manual dialing. You dial the number on your telephone set, and after
hearing the answer tone on your handset, you type ATD on your
keyboard and hit RETURN. Then hang up the headset. Unless you have
a specific need to dial in this manner, we recommend you use the first
method, where the telephone number is entered on your keyboard.
The Series II Modem gives you several choices of dialing methods. You
can use tone or pulse dialing, by inserting a letter T or a P in the
command string. (See the section on Dial Modifiers.)
You can also configure the modem to either wait for and detect dial
tones and busy signals (which we call “Wait-for-Dial-Tone” dialing or
“Smart” dialing), or work with timed pauses without dial tone and
busy signal detection (which we call “Blind” dialing; see Section on “
X” Command.)
Note: There is another method of dialing, called “DTR Dialing”, where
by manipulating the DTR signal on pin 20 of the RS-232C/V.24
interface, a number stored in the modem's memory is automatically
dialed. See the section on the DTR Dialing ($D) command for details.
Continuous Redial A: or :
If you select the Wait-For-Dial-Tone method of dialing (see X3 or X4
command), you can command the Series II Modem to continuously
redial a busy number until your call is answered. This is done with the
A: command.
52
CHAPTER 5: Command Mode
This command would be used only if you had already reached a busy
number after executing a normal dial command. You simply enter A:
(you need not enter AT, nor do you need to hit RETURN), and the
modem will redial the number for you. If you again reach a busy signal,
it re-dials again and again until it no longer detects a busy signal. You
can stop the Series II Modem from re-dialing by pressing any key.
Another method used to cause the modem to redial a phone number
continuously is to enter a colon : at the end of the phone number. The
result is the same as if you had entered A: after personally observing
that the number was busy on the first dialing attempt. Using the colon
in the dialing string is a step saver.
Dialing a Stored Number N
A telephone number that you have stored in the Series II Modem’s
number memory may be automatically dialed by entering ATNn where
n = 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9. For example, a number stored at N3
would be dialed by entering ATN3 and RETURN. Do not include the
letter D in this command, or the stored number will be erased (also see
Section 5.4.3., on Phone Number Memory Commands).
DTR Dialing $D
An alternate method of causing the Series II Modem to automatically
dial is DTR Dialing. Data Terminal Ready (DTR) is a signal that comes
into the modem from the terminal or computer to which it is
connected, on pin 20 of the RS232C interface. In DTR dialing, the
modem automatically dials a stored number as soon as it receives a high
DTR Signal. The DTR dialing method is popular in synchronous appli-
cations.
To activate DTR Dialing, enter AT$D1 and hit RETURN. The modem
dials the phone number stored in the N0 location of memory when it
receives a high DTR signal. DTR must remain high for the duration of
the call, until disconnect. To deactivate DTR dialing, enter AT$D0 and
hit RETURN.
Note that when you use DTR Dialing in a synchronous application, you
need to make sure DIP-Switch #8 is in the UP position to disable V.25bis
Command mode.
53
SERIES II INTELLIGENT DATA/FAX MODEMS
Voice/Data Dialing $VD
Another alternate method of causing the Series II Modem to
automatically dial is Voice/Data Dialing. With Voice/Data Dialing, the
modem automatically dials the phone number stored in the N1 position
of memory whenever the Voice/Data switch is toggled. You must first
enter AT$VD1&W0<CR>. This command string enables Voice/Data
dialing when the Voice/Data toggle switch is activated. To disable
Voice/Data Dialing (default), enter the command AT$VD0 W0<CR>.
5.4.2 Dial Modifier Commands
There are several command characters that can be included within a
dialing command (following the letter D), called “Dial Modifiers”. They
have various functions, including the selection of Pulse or Tone Dialing,
pauses in the dial sequence, automatic re-dials if a number is busy, and
reverting to the Command mode or switching to the Answer mode after
dialing.
Pulse or Tone Dial P or T
The Series II Modem dials numbers using either pulse or tone dialing,
or a combination of both methods. Pulse dialing is a method used by
rotary-dial telephones, which involves the timed opening and closing of
line relay.
Tone dialing is the method used by push-button (touch tone) telephones,
and is sometimes referred to as DTMF, or Dual-Tone Multi-Frequency
dialing.
The method used is selected by including a P for Pulse or a T for Tone
in the dialing command, right before the digits you wish to have dialed
in that manner.
For example, you would pulse-dial the number 555-1212 by entering
ATDP5551212 and hitting RETURN. You could tone-dial the same
number by entering ATDT5551212 and hitting RETURN. If neither
Pulse nor Tone dialing is specified in the dial command, the Series II
Modem uses whatever method used last. If the modem has been reset or
just powered up, it uses Pulse dialing, even if the letter P is not included
in your dial command.
54
CHAPTER 5: Command Mode
Nearly all telephone systems in the U.S. are now compatible with tone
dialing. Since that is the faster method, you will probably choose the
tone method for your dialing.
An example of combining pulse and tone dialing could involve a PBX
system where 9 had to be pulse-dialed first, then the rest of the number
tone-dialed after pausing for a second dial tone. The number would be
dialed by entering ATDP9, T5551212 and RETURN. (The comma
causes a pause, which we’ll explain soon.)
Set Pulse Dial Ratios &P
This command sets the time ratios between the open and closed
portions of the dialing pulse frequencies. To select a dialing pulse ratio
of 60 mSec/40 mSec, enter AT&P0. To select a ratio of 67 mSec/
33 mSec, enter AT&P1. The factory default is &P0.
Automatic Pauses in Dialing ,
You can cause the Series II Modem to pause during the dialing
sequence by entering a comma character where the pause is desired.
This pause lasts two seconds. If a longer pause is desired, more than one
comma may be entered consecutively, with each comma causing a two
second pause. You also have the option of changing the length of the
pause caused by the comma, from two seconds to any other value from
0 up to 255 seconds. This is done by setting S-Register S8 (refer to
Chapter 6). Each comma in a dialing command counts as one of the
sixty allowed characters.
Long Space DisconnectY
When two modems are connected in Normal mode (that is, without
error correction) there is no "polite" means of requesting a disconnect.
A link disconnect request packet is sent under reliable connections. As a
result some "garbage" may be received when a hang-up command is
issued. The Y1 command enables the modem to use the break signal
which accomplishes the hang-up as an instruction to shut off its receiver
and disconnect (both modems must have Y1 enabled for this feature to
be effective). Y0 (factory default) disables this function.
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SERIES II INTELLIGENT DATA/FAX MODEMS
Wait for New Dial-Tone W
A W inserted in the dialing command causes the Series II Modem to
wait for another dial tone, and not resume dialing until another dial
tone is detected.
It is not necessary to enter a W at the beginning of the dialing
command to wait for a modem dial tone, because the modem
will do that first (pause automatically).
In order for this command to work, you must select Wait-For-Dial-Tone
dialing with the X2 or X4 command, so that your modem will be able to
detect the dial tone.
Return to Command Mode after Dial Command Execution ;
A semicolon (;), entered as the last character of a dialing command
causes the Series II Modem to return to the Command mode
immediately after executing the command, instead of waiting for a
carrier signal and going on line.
For example, entering ATDT5551212; would tone-dial the number, and
do nothing afterwards except go back into Command mode. This can
be useful in dialing applications where modem data transfer is not
desired, such as voice communications, or in applications involving
the use of touch tones as a data entry method, such as bank-by-phone.
Reverse the Mode of Operation R
In certain operations you may need to reverse the mode of operation
for your modem from originate to answer or answer to originate so that
it would answer the phone and go into answer mode. This command
turns off the reversing function with the R0 command and turns it on
with the R1 command with the modem in either command mode. If
you want to reverse from the originate mode, use R (with no number)
in the dialing string.
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CHAPTER 5: Command Mode
Flash On Hook !
Some switchboard systems react to a momentary On Hook. An
exclamation mark inserted in the command causes the modem to
“flash” on hook for a half of a second, as if you had held the switch hook
button on a telephone down for a half second.
For example, to flash On Hook after dialing the number 555-1234
in order to transfer to Extension #5678, you might enter
ATDT5551234,,!5678. The commas cause a 4 second pause (just to
be safe).
"Calling Card" Detect Tones $
The Series II Modem has the capability to detect AT&T "calling card"
tones for the purpose of utilizing the user's calling card number to
originate an on-line connection. An $ symbol placed in the dialing
string causes the modem to pause and wait for an AT&T "calling card" or
a 1600 Hz tone (prevalent in the United Kingdom). When the tone is
detected, the rest of the dialing string is processed. If no tones are
detected within the time period set by S-Register S7 (default 45
seconds), the modem will abort by indicating a NO CARRIER message.
Hitting any key also aborts the $ command.
The following is an example of this command:
ATDT101099907247465500$0123 4567 8910 1112
Quiet Answer @
The @ command causes the Series II Modem to wait before processing
the next symbol in the dialing string. The wait is for one or more
ringbacks followed by 5 seconds of silence. If the time specified by
S-Register S7 passes before the rings and silence, a NO ANSWER (R)
result code is processed. The @ command is used for accessing a system
that does not provide a dial tone.
For example, ATDT5551212@7465500 causes the Series II Modem to
dial the first number (555-1212) and wait for the time specified in S7
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SERIES II INTELLIGENT DATA/FAX MODEMS
for at least one ringback and 5 seconds of silence. If a busy signal is
detected, the Series II Modem hangs up and generates a BUSY result
code. If it does not detect 5 seconds of silence, a NO ANSWER result
code is generated after hanging up. If 5 seconds of silence is detected,
the second number (746-5500) is then dialed.
5.4.3 Phone Number Memory Commands
Storing Phone Numbers D...N
A telephone number and command line of up to sixty characters may
be stored in the Series II Modem’s number memory. As many as ten of
these numbers may be stored. Each number will be given a name, using
the codes N0, N1, N2 up to N9.
A phone number is stored by entering ATD, then the number as it
would be dialed, along with any P, T, R, ; or comma characters, and
then entering N followed by the number’s “name,” which would be
any number from 0 through 9, and then hitting RETURN.
For example, the tone-dialed number 1-612-631-3550 would be stored
as number N3 by entering ATDT17247465500N3 and RETURN. The
number is not dialed with this store command. After storing a number,
check to see that it has been stored correctly by typing ATL and hitting
RETURN.
When phone numbers are stored, the entire command line is also
stored so that you can effectively create a macro for each number. For
example, if you know a particular number needs to have extended
result codes, detect busy or dial tone, error correction, Xon/Xoff flow
control, pacing, and data compression enabled, the command line
would be:
ATX4&E1&E5&E13&E15DT17247465500N3
This would store the entire command at location N3.
Number Linking NN
You may command the Series II Modem to dial another number
automatically if the first number dialed is busy. This would be useful in
a situation where a computer can be accessed through more than one
phone number. This is called “linking”.
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CHAPTER 5: Command Mode
To link the number in N1 to the number N2, simply enter ATN1N2 and
hit RETURN. Several numbers can be linked in the same command.
For example, you could link N1 to N2 to N3 to N4 by entering
ATN1N2N3N4 and RETURN or you could link N1 to N2 and back to
N1 and then back to N2 by entering ATN1N2N1N2 and RETURN.
The only limit on the number of numbers that can be linked is the 60
characters allowed in a command line. Number linking can not be used
with blind dialing, since busy signals would not be detected. You would
have to select the Wait-for-Dial tone dialing method using the
X Command in order to use the Number Linking feature.
Listing Numbers Stored in Memory L
Telephone numbers that you have stored in the Series II Modem’s
memory may be listed and displayed with the L command. It will display
all ten stored N numbers in a format like that shown below. All digits
and command letters will be shown. The phone number’s single-digit
designation (0 through 9) is shown first, followed by the complete
dialing command and telephone number as originally entered.
Simply enter ATL and hit RETURN to display these numbers on your
video screen or printer. An example of an L command listing is shown
below:
0
1
2
3
4
5
6
7
8
9
DT14922345678
DT17245551212;
DP9,T14929876543
DT3738315,12101,17247465500
DT7465500R
DP9,4258513
DTX4&E1&E5&E13&E15DT17247465500
DT12138880123
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SERIES II INTELLIGENT DATA/FAX MODEMS
5.4.4 Configuration and Default Storage
Commands
Store Configuration & S-Register Parameters
in Non-Volatile Memory &W
The Series II Modem can store configuration parameters and S-Register
values in its nonvolatile read/write Random Access Memory (RAM)
memory. The &W command does this, which prevents any re-
configuration from being lost on a power-down or Reset (ATZ)
condition.
(access/phone number)
(credit-card number)
&W0 (or AT&W) causes the Modem to store your customized AT
command settings and S-Register values in its nonvolatile RAM. &W0
also sets the modem so that it reads your customized settings stored in
nonvolatile RAM when powered down or reset. (The &W0 command
only changes the settings stored in nonvolatile RAM that you specifically
intend to alter. All other default parameters are applicable.)
&W1 causes the Modem not to store your customized settings to
nonvolatile RAM so that, after powering down or resetting the modem,
it reads the factory default settings stored in ROM.
Loading Factory Defaults &F
The &F command provides a choice between customized configuration
settings in RAM and the factory default configuration settings in ROM.
The &F8 and &F9 commands define the function of the &F command.
The Series II Modem is shipped from the factory with a pre-configured
set of command and S-Register default settings. This set of factory de-
faults can be recalled by issuing the &F command.
In addition to being able to recall the factory-installed defaults, the &F
command can also recall those defaults stored under &W0.
This is done using the &F9 command. If you have stored parameters
with the &W0 command and wish these settings to always be used as
your defaults, you would enter &F9&W0.
To return the &F command to read factory installed defaults, enter
&F8&W0. &F8 is the factory default.
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CHAPTER 5: Command Mode
Many datacomm program issue the &F command automatically—the
&F9 command allows the user to select their own factory defaults. Note
that the &F8/&F9 commands should be used with &W0.
Following is a summary of how the &F and Z reset commands interact
with the &W command; note how the &F reset command operates
differently from the Z reset command:
Previous Command AT&F
Power-On and ATZ
AT&W1 (default)
AT&W0
AT&F8&W0
AT&F9&W0
ROM
ROM
ROM
NVRAM
ROM
NVRAM
NVRAM
NVRAM
Modem Reset Z
The Z command can be used to reset the entire Command Mode
buffer and the result is the same as if you had disconnected, and
then reconnected power to the modem. When an ATZ command is
executed, the state of the &W command determines where the default
values originate. &W0 defaults come from RAM and &W1 defaults
come from ROM.
Unix UUCP Spoofing $SP
The Series II Modem can be configured in a Unix environment that
employs ACK flow control as a means of monitoring data integrity. The
Modem can do “UUCP spoofing”, where the modem is able to generate
ACKs at the DTE interface. Data is transmitted more time efficiently
because the delay of waiting for data to be received, then for an ACK
to be returned at the remote end, is eliminated. The $SP1 command
enables UUCP spoofing and the default command $SP0 disables
UUCP spoofing.
V.32terbo Enable/Disable #V (336 Only)
Other types of V.32/V.32bis modems have problems handshaking when
the Series II Modem 336 (MD1641A) includes V.32terbo mode (19,200 bps)
in its handshaking process. The bits that are used in the rate sequence for
V.32terbo can cause handshaking failure.
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User Guide for Series II Modems
The #V command gives the user the option of including V.32terbo as
part of the handshaking process in both Orignate and Answer modes.
Entering AT#V0&W0<CR> includes the V.32terbo mode in
handshaking. Entering AT#V1&W0<CR> disables the Series II Modem
336 from using V.32terbo mode in the handshaking process (default).
Async/Sync Mode Switching &M
This command can be used to set the on-line mode to either
synchronous or asynchronous. AT&M0 will set the Series II Modem to
Asynchronous mode, and all communications will be asynchronous in
both On-line and Command modes. AT&M1 causes the Modem to com-
municate asynchronously when in Command mode and switch to syn-
chronous mode while on-line. The modem defaults to &M0
(asynchronous communications) on reset or power-up.
Synchronous Transmit Clock Select &X
The &X command selects the Synchronous Transmit Clock Source in
conjunction with DIP-Switch #11. DIP-Switch #11 in the UP position
enables External clocking. DIP-Switch #11 in the DOWN position
enables Internal clocking (default position). External clocking is when
the DTE provides transmit clocking to the modem on pin 24 of the
RS232C interface.
&X0 is the default setting, which allows DIP-Switch #11 to control
Internal/External Clocking (default Internal). Internal clocking is
when the modem provides transmit clock to the DTE on pin 15 of the
RS-232C/V.24 interface. The &X1 command overrides DIP-Switch #11
and selects External clocking. If DIP-Switch #11 is UP (External
clocking), you can not override Internal clocking. &X2 enables Slave
Clocking. The &X2 Command causes the Series II Modem to generate
the transmit clock timing (pin 15) from the receive clock (pin 17) from
the DTE (therefore 15 and 17 are the same). In this mode (Slave
Clocking), all timing is controlled by the receive clock.
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Chap5:CommandModeter
5.4.5 Command Response (Result Code)
Commands
Echo Command Mode Characters E
If the Series II Modem is connected to a full-duplex computer, it may
be necessary for the modem to be configured to echo back characters
entered while in the Command Mode in order for them to be displayed.
The E command is used to configure the Command Mode echo, with
ATE0 disabling the echo and ATE1 enabling the echo (default).
Result Codes Enable/Disable and No Response Answer Q
The Q command enables or disables Result Codes and the No Response
Answer mode of operation. Result Codes may be disabled altogether in
certain applications, such as computer-controlled auto dialing, using
the Q command. ATQ1 disables Result Code transmissions. ATQ0 (or
ATQ) enables Result Code transmission.
Regarding No Response Answer, you may want the answer mode
handled without responses and echo turned off, but want the originate
mode still intelligent. This is called the No Response Answer mode.
ATQ2 selects the No Response Answer mode. If you do not select any
mode, the factory default setting (enable Result Codes) is automatically
selected.
Result Codes ("Series II" or "Standard AT") &Q
The Series II Modem gives you a choice between the Series II Result
Codes, and Result Codes that more closely match the standard AT
command set responses (see section 5.3).
AT&Q1 selects AT responses with no Reliable/Compression
modifiers. With this command, the terse result code for CONNECT 2400
is 10.
AT&Q0 selects Series II responses with Reliable/Compression
modifiers. With this command, the terse result code for CONNECT 2400
is 9.
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SERIES II INTELLIGENT DATA/FAX MODEMS
Result Codes (Verbose/Terse) V
The V command controls whether the Series II Modem’s result codes
are displayed as word (“verbose”) or single digit (“terse”) messages.
For example, if after dialing, no carrier signal is detected, the resulting
message can be displayed either as NO CARRIER, or as the digit 3.
Entering ATV0 (or ATV) causes the Modem to display the Result Codes
as digits, while ATV1 displays them as words. If you do not select a
method, the factory default setting causes the modem to display Result
Codes as words.
Result Codes (Basic and Extended) and Call Progress
Selection X
The X Command is used to select one of two possible dialing methods
(“dumb” or “smart”), and to select various response combinations related
to these methods. You can choose to have certain responses suppressed,
or whether or not you want speed indications along with the CONNECT
responses. You can also pick and choose certain responses in order to
match up with “Standard AT” responses. (Refer to Appendix G for a
summary of Result Codes.)
The Series II Modem provides “Basic” and “Extended” Result Code sets.
The difference between the two is the Basic set provides one response
(CONNECT) to indicate a connection, while the Extended set provides
several responses for different speeds (CONNECT, CONNECT 2400,
CONNECT 4800, CONNECT 9600, CONNECT 14400, CONNECT 19200,
CONNECT 21600, Etc.).
When the Extended set is chosen, you also have the option of matching
them up with Standard AT 2400 response code sets, by including or not
including the BUSY and/or NO DIAL TONE responses while excluding
the DIAL TONE response. The X command is used to select which
responses are provided.
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CHAPTER 5: Command Mode
Regarding the Series II Modem’s method of dialing, the Modem can
detect standard dial tones and busy signals. This capability (“smart
dialing”) allows the modem to wait for a dial tone, and when one is
detected, to begin dialing immediately.
The Modem also can detect a distant busy signal if, after dialing, it
reaches a busy number. This is useful because it allows the modem to
immediately abandon a call, rather than wait 45 seconds for a carrier
signal that will never come. S-Register S7 defines the wait for carrier
time (refer to Chapter 6).
The Series II Modem gives you a choice between the wait-for-dial-tone
(“smart”) method we just described, and blind (“dumb”) dialing, where
instead of detecting actual dial tones, the modem relies on timed
pauses. When the wait-for-dial-tone method is chosen, the busy signal
detection capability is also activated. The X command is also used to
select which dialing method is used.
Five different X commands are available (X0 through X4), with five
different effects on the Modem’s Result Codes.
X0
Provides the basic (short) result codes and provides
“dumb” dial capabilities.
X1
Provides the extended result codes and provides “dumb”
dial capabilities.
The remaining X commands affect Call Progress, and turn on Extended
Result Codes.
X2
Looks for dial tone only and will not provide a busy
response.
X3
X4
Looks for busy only and not look for dial tone.
Looks for dial tone and for busy.
The factory default setting is X0, which selects Basic Result Codes
and the blind (“dumb”) method of dialing.
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SERIES II INTELLIGENT DATA/FAX MODEMS
5.4.6 Phone Line Conditioning Commands
Guard Tones &G
The &G command is used to control the presence or absence of guard
tones from the transmitter when in Answer mode, at either 1200 or
2400 bps. Guard tones are used in Europe and other areas for the
modem to function in the telephone systems. Guard tones are not used
in the United States. &G0 (default), turns off CCITT guard tones. &G1
turns on 550 Hz guard tones. &G2 turns on 1800 Hz guard tones.
Phone Line Monitoring Speaker M
The Series II Modem has an internal on-board speaker, which functions
like the speaker in a telephone handset, to enable you to monitor
phone line activity. The M command can be used to determine when
the speaker is operational.
Entering ATM0 disables the speaker completely, while ATM1 causes the
speaker to be on only until a carrier signal is detected. ATM2 causes the
speaker to remain on at all times. ATM3 causes the speaker to be on
during dialing and off during handshake. ATM1 is the default setting,
and the one that should be used in most applications.
Enable or Disable Recognition of Remote Digital Loop
Signal &T
The Series II Modem has several self-test features (covered in Chapter
8). The tests are activated with different U commands, such as ATU1,
and so forth. The &T command is a phone line conditioning command
that enables or disables the modem’s ability to recognize the Remote
Digital Loop (RDL) test signal.
The AT&T4 command lets the Modem respond to a RDL signal, and
places itself in digital loop. The AT&T5 command causes the modem
to ignore the RDL signal. The factory default is &T5.
Enable/Disable Trelis Coded Modulation #T
This command enables or disables the Trellis Coded Modulation of the
Series II Modem. There is usually no need to disable (turn off) Trellis
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CHAPTER 5: Command Mode
codings except under an unusual line condition called impulse noise.
AT#T0 turns Trellis coding off and AT#T1 turns Trellis coding on
(factory default).
Fallback Modes When On-Line #F
If line conditions deteriorate, the Series II Modem automatically drops
its transmission speed (“fallback”). The #F command controls the
different ways the Modem falls back. During operation, if the error rate
becomes too great, the modem performs a retrain. If after the retrain,
the error rate is still too high for 33600 bps operation, the modem
initiates a retrain at 4800 bps. If after the first retrain the modem
returns on line at 33600 bps, the modem then starts a counter and a
timer. If three retrains occur within a two minute period, the modem
falls back to 4800 bps.
Entering AT#F0 (or AT#F) allows no fallback when on-line. AT#F1
allows the Modem to fallback (based on the error rate or if three
retrains have occurred within a two minute period) from 33.6K to 31.2K
to 28.8K to 26.4K to 24K to 21.6K to 19.2K to 16.8K to 14.4K to 12K to
9.6K to 4.8K bps. The AT#F2 command enables incremental fall back
from 33.6K to 4.8K, but also enables incremental fall forward (from
4.8K to 33.6K) if the phone line improves. AT#F2 is the factory default
setting.
Enable/Disable Lowspeed Fast Connect $FC (336+ Only)
With the Series II Modem 336+ (MD1640A), entering
AT$FC0&W0<CR> sets up the data pump so that it will not transmit a 5
second 2100 Hz signal. Entering AT$FC0&W0<CR> allows the modem
to transmit a 5 second 2100 Hz signal and is the factory default.
Cleardown at Disconnect &CD
The &CD command is used for control of cleardown at disconnect in
V.32, V.32bis, V.34 and V.34 enhanced modes.
A cleardown usually adds 1-2 seconds to the time it takes for the modem
to go on-hook after a disconnect. A cleardown makes a disconnect by
the remote modem easier to detect and a subsequent re-connection
more likely. Enter AT&CD0&W0<CR> to execute a cleardown at
disconnect (default); and enter AT&CD1&W0<CR> to disable the
cleardown function.
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SERIES II INTELLIGENT DATA/FAX MODEMS
Auto Speed Detect #A
The function of the #A command is to detect and select the operational
data rates (the “starting” speeds) with which the Series II Modem uses
for initial handshake and speed selection.
Remember, this command does not control the originating data rate of
the modem (that is done by the Modem Baud Rate command $MBn),
but only the Answer mode “starting” speeds. Entering
AT#A0 (or AT#A) causes the Modem to operate starting at 33,600 bps,
with fallback to 28,800 to 19,200 to 14,400 to 9600 to 4800 to 2400 to
1200 and to 300 bps. Entering AT#A1 causes 33,600 bps operation only.
Entering AT#A2 causes the modem to operate at starting speeds of
33,600 bps, with incremental fallback to 28,800, 19,200, 14,400, 9600
and 4800 bps. The AT#A3 command causes the modem to begin
operation as a V.22bis modem at 2400 bps, with fallback to 1200
to 300 bps. AT#A0 is the factory default value.
5.4.7 RS232C Interface Control Commands
Carrier Detect Control &C
The &C command allows you to control the status of the Carrier Detect
signal (CD, Pin 8) on the RS232C line. You have four choices.
You can force the signal high, or allow it to act normally, or force the
modem to reset when CD drops, or set it to stay high until the modem
disconnects, go low momentarily, and then go high again. The last
option is useful with some CBX phone systems and mainframe front
ends, which require CD to act in this manner.
To allow CD to act normally, enter the command AT&C1 (the factory
default setting). To force CD on, enter AT&C0. To reset the modem to
its current parameters when CD drops, enter AT&C4. To set up CD so
that it drops for one second on disconnect and then comes up again,
enter AT&C2. (If you want the drop time to be something other than
one second, use S-Register S24 to change this value. Refer to the
Chapter 6 instructions for S24.)
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CHAPTER 5: Command Mode
Data Terminal Ready Control &D
Data Terminal Ready (DTR) on Pin 20 of the RS232C interface is
required in order for the Series II Modem to operate. A high DTR
signal tells the modem that the device to which it is connected is active,
or "ready" to communicate through the modem. If the signal is not
being provided on the RS232C interface, you can force DTR high with
DIP-Switch #1 (Chapter 9).
DTR has some other Modem functions. DTR can be used to trigger a
dialing sequence, called DTR Dialing. The condition of DTR can also
be used to cause the modem to reset to its default parameters, just as if
you had given the modem an ATZ command. To do this, enter the
command AT&D3 and hit RETURN.
The modem will now reset itself whenever DTR is dropped from On to
Off, and will also go on-hook (hang up) if it is on-line.
Entering AT&D0 or AT&D causes the Modem to ignore DTR. Entering
AT&D1 causes the modem to go on-hook (hang up) with loss of DTR.
The modem enters Command mode when DTR goes high again. Auto-
answer is disabled while DTR is low. Entering AT&D2 causes the modem
to go on hook with loss of DTR. The modem enters command mode
when DTR goes high again.
Clear to Send Control &R
The &R command allows you to control the Clear to Send signal (CTS,
Pin 5) on the RS232C interface. You have three choices. You can force
the CTS signal high, allow it to act normally, or set it to stay high until
the modem disconnects, go low momentarily, and then go high again.
The last option is useful with some CBX phone systems and mainframe
front ends, which require CTS to act in this manner.
To allow CTS to act normally, enter the command AT&R0. To force
CTS on, enter the command AT&R1 (this is the factory default setting).
When the modem goes on-line, CTS still provides flow control. To set
up CTS so that it drops for one second on disconnect and then comes
up again, enter the command AT&R2. (If you want the drop time to be
something other than one second, use S-Register S24 to change this
value. Refer to Chapter 6).
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SERIES II INTELLIGENT DATA/FAX MODEMS
Data Set Ready Control &S
The &S command allows you to control the status of the Data Set Ready
signal (DSR, Pin 6) on the RS232C interface. You have three choices.
You can force the signal high, allow it to act normally, or set it to stay
high until the modem disconnects, go low momentarily, and then go
high again. The last option is useful with some CBX phone systems
and mainframe front ends, which require DSR to act in this manner.
To allow DSR to act normally, enter the command AT&S1 (the default
setting). To force DSR on, enter the command AT&S0. To set up DSR
so that it drops for one second on disconnect and then comes up again,
enter AT&S2. (If you want the drop time to be something other than one
second, use S-Register S24 to change this value. Refer to Chapter 6.)
CTS/RTS Interaction Control &RF
In typical operation, Clear to Send follows Request to Send when the
modem is on-line. In other words, if RTS goes off, CTS goes off in
response. The &RF0 command enables CTS to follow RTS. In some
applications, however, it may be necessary for CTS to operate indepen-
dently of RTS. &RF1 allows CTS to operate independently regardless
of the state of RTS, and is the factory default. If this is the case, refer
to the &R command for control of the Clear to Send signal.
DSR/CD Interaction Control &SF
In typical applications, Data Set Ready (DSR) follows Carrier Detect
(CD). &SF0 enables DSR to follow CD, and is the factory default. &SF1
enables DSR to operate independent of CD. If this is your application,
refer to the &S command for control of the Data Set Ready signal.
5.4.8 Error Correction Commands
You can use AT commands to place your Series II Modem one of three
V.42 (error correction) modes of operation. These are the Normal,
Auto-Reliable, and Reliable modes.
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CHAPTER 5: Command Mode
Normal Mode &E0
In Normal mode of operation, the Series II Modem’s V.42 error correc-
tion capabilities are disabled, and the modem functions as a non-error-
correcting modem.
Auto-Reliable Mode &E1
In Auto-Reliable mode during the handshaking procedures at the start
of the on-line connection, the Series II Modem automatically
determines whether or not the modem with which it is communicating
is using V.42 error correction. If the Modem determines that the other
modem is using V.42, it switches itself into MNP or LAPM Reliable
(V.42) mode and its error-correction capability is enabled. If it is deter-
mined that the other modem is not using V.42, the Modem remains in
Normal mode, without error correction. The default setting is Auto-
Reliable mode (&E1).
The method the Modem uses to determine if the modem it calls is a
V.42 modem involves the use of a “Link Request”.
When the Series II Modem is in Auto-Reliable mode and originates a
call, it goes through normal handshaking procedures just like any dial-
up modem. After establishing the on-line connection, the Modem
transmits a Link Request message to the answering modem. (The Link
Request message is generally about 33 coded characters.) If the
answering modem replies with an appropriate V.42 acknowledgment
response, the Modem switches into Reliable mode. Otherwise it stays
in Normal mode. This V.42 Link Request handshaking procedure
generally takes about five seconds.
When operating in V.42 Reliable mode, the Series II Modem uses its
memory, or buffer, to store data as it is received. During periods of
error-caused retransmissions or compression slowdowns, this buffer
may fill up. To prevent buffer overflow and subsequent loss of data, the
modem uses "flow control" to signal the computer attached to its RS232C
port that the modem buffer is close to being full. This causes the com-
puter to pause in its data transmission until the modem is able to empty
its buffer sufficiently to accept more data, at which time the modem
signals the computer that it may resume transmission. (Flow Control is
discussed in section 5.4.9.)
71
SERIES II INTELLIGENT DATA/FAX MODEMS
Reliable Mode &E2
In Reliable mode, the Series II Modem uses its V.42 error correction
capabilities during all transmissions, and must be connected to another
modem with a similar protocol activated (MNP or LAP-M).
V.42 Mode Select #L
The V.42 standard implements both MNP Class 3 & 4 and LAP-M error
correction methods. The V.42 Mode Select command (#L) selects which
type of error correction (MNP or LAP-M) your Series II Modem uses for
transmissions.
The various #L command options are as follows.
#L0 Command
The #L0 Command allows a pair of
modems to negotiate which V.42 mode
(MNP or LAP-M) will be used in their
transmissions.
Originate Mode
a. If both modems have LAP-M capability,
the modems use LAP-M mode.
b. If one or both modems do not have LAP-
M capability and both have MNP, the
modems use the MNP mode.
#L0 Command (cont'd)
Answer Mode
a. The answering modem responds to either
an MNP Link Request or LAP-M Originator
Detection Pattern (ODP) signal depending
on which the originating modem issues.
#L1 Command
#L2 Command
The #L1 Command sets your modem to
MNP error correction and disables LAP-M.
This command is for Originate mode only.
In Answer mode, the modem still accepts
MNP or LAP-M.
The #L2 Command sets your modem to
LAP-M error correction, and disables MNP.
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CHAPTER 5: Command Mode
This command is for Originate mode only.
Answer mode still accepts MNP or LAP-M.
#L3 Command
In the prior commands, the modems use a
two phase process to establish a V.42
connection (detection to establish whether
the remote modem is also error correcting,
and then protocol establishment to deter-
mine parameters and to establish the error
correction connection). If you know that
the other modem is a V.42 error correcting
modem, and you wish to use LAP-M, the
#L3 command disables the detection phase
and goes directly to protocol establishment.
Both modems must have #L3 in effect.
Auto-Reliable Buffering $A
In Auto-Reliable mode, the modem is given four seconds to establish a
Reliable connection. After this four-second period, the modem drops to
Normal mode. Any data which is received during this period is typically
discarded. The $A command can be used to cause the modem to buffer
(save) data that is received during this Auto-Reliable time-out period.
This data will then be output by the modem after the
CONNECT message.
AT$A0 = Discard data received during auto-reliable time period.
AT$A1 = Buffer data received during auto-reliable time period.
The factory default is $A0.
Enable/Disable Auto Reliable Fallback Character $F
In Auto-Reliable mode, the modem is given four seconds to establish a
Reliable connection. If a single CARRIAGE RETURN is received from
the remote modem during this four second period, the Auto-Reliable
modem assumes that the remote modem is not in Reliable mode and
drops to Normal ( non-error correcting) mode. The CARRIAGE
RETURN is the only character which causes the modem to drop to
Normal mode. Any other character will either be buffered or discarded.
73
SERIES II INTELLIGENT DATA/FAX MODEMS
The $F command can be used to disable this fallback-to-Normal-due-to-
CARRIAGE-RETURN feature.
The Auto-Reliable fallback character ($F) and Auto Reliable buffering
($A) commands can be used together to cause the modem to buffer all
data received up until the CARRIAGE RETURN, and then drop to
Normal mode. All data received will then be output following the
CONNECT message.
AT$F0 = Do not fall back to Normal if CARRIAGE RETURN
received.
AT$F1 = Fall back to Normal mode if CARRIAGE RETURN
received.
The factory default is $F0.
Retransmit Count $R
If errors are received during a Reliable connection, the modem
re-sends the block of data which contained an error. With the $R0
command, if another error occurs, the block will be re-sent again. The
modem counts the number of times that a data block is re-sent. If the
same block of data is resent 12 times and still has not been received
properly, the modem assumes that the transmission line is unsuitable
for transmission, and abort the connection.
This retransmit counter is disabled by the $R1 command. When the
retransmit counter is disabled, the modem keeps trying to send data
and will not abort, no matter how many times the same block is resent.
AT$R0 = Disconnect if retransmit count is exceeded.
AT$R1 = Do not disconnect due to retransmits.
The factory default setting is $R0.
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CHAPTER 5: Command Mode
V.42 Error Correction/300bps $E
At 300 bps, error correction is not typically used. $E1 lets the Series II
Modem function at 300 bps in either Normal (&E0), Auto-Reliable
(&E1) or Reliable (&E2) mode. $E0, which is the Modem’s default,
disables 300 bps/V.42 error correction altogether.
AT$E0 = No V.42 Error correction at 300 bps.
AT$E1 = V.42 Error Correction at 300 bps.
The factory default setting is $E0.
5.4.9 Flow Control Commands
Flow control refers to the techniques used by computer devices to stop
and restart the flow of data to and from each other. Flow control is
necessary so that a device does not receive more data than it can
handle. In the case of the Series II Modem, there is a need for flow
control in both directions. As illustrated on the next page, flow control
for data passing from your computer to the modem is called Modem-
Initiated Flow Control and flow control for data passing from the
modem to your computer is called Computer/Terminal-Initiated
Pacing.
The Series II Modem supports both hardware and software Modem
Initiated Flow Control. On the Computer/Terminal-Initiated Pacing
side, it supports hardware and software flow control, and a special
®
version used by Hewlett-Packard compatible systems called ENQ/ACK
Pacing. The Modem allows hardware and software pacing to be passed
through the modem to the other end of the link so that your computer
or terminal can control data start/stop activity through your modem.
This is called Xon/Xoff Pass-Through. To state it simply, “Flow Control”
is something the modem does to the computer, while “Pacing” is
something the computer does to the modem.
75
SERIES II INTELLIGENT DATA/FAX MODEMS
Modem-Initiated Flow Control
RS/232/V.24
data flow
Computer or
Terminal
Modem
Computer-Initiated Flow Control
Computer,
Terminal, or
Printer
RS/232/V.24
data flow
Modem
Figure 5-2. Flow Control and Pacing
Hardware Flow Control &E4
With Hardware Flow Control, the modem uses its RS232C interface to
control the flow of data from the computer or terminal to which it is
attached. The CTS (Clear to Send) signal on Pin 5 of the RS232C
interface is brought low to stop the flow of data, and is brought high
to restart it. When you select Hardware Flow Control as your Modem
Initiated Flow Control method, you will also be selecting it for Pacing.
The difference between the two, however, is that Modem-Initiated Flow
Control uses the Pin 5 CTS output signal, while Pacing uses the Pin 4
RTS input signal.
Modem commands are used to select the method of flow control used
by the Series II Modem when its error correction capabilities are used.
These commands are covered in Section 5.4.9. If neither method is
selected, the modem defaults to no flow control (&E3).
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CHAPTER 5: Command Mode
Xon/Xoff Flow Control &E5
Xon/Xoff is the most commonly used method of flow control. Under
this method, control characters known as “Xon” and “Xoff” are inserted
by the modem into the data to start and stop the flow of data from the
computer or terminal to which the modem is attached. Xoff, which is a
Control-S, stops the flow of data, and Xon, which is a Control-Q, restarts
it. With regard to Binary Data, Xon/Xoff flow control is not recom-
mended because an Xoff character may be part of the data and would
trigger an Xoff of the modem or software package, which would halt
data flow.
Xon/Xoff Pass-Through &E7
So far, you have had three choices to make regarding pacing:
1. You can set the modem to respond to Xon/Xoff pacing.
2. You can set the modem to respond to RTS pacing.
3. You can set the modem to ignore pacing completely.
Well, we’re not done with pacing yet. There’s another choice you can
make (which actually can apply to both pacing and modem-initiated
flow control, although it applies mainly to pacing) and that is
something called “Xon/Xoff Pass-Through.”
This means that if your modem is set to respond to Xon/Xoff com-
mands, you can have the modem do one of the following:
1. The modem responds to the Xon and Xoff pacing commands
while at the same time allowing these commands to pass through
the modem and on to the remote location. We call this “Respond,
Pass-Through”.
2. The modem responds to Xon/Xoff pacing, but does not allow the
pacing signals to pass through the modem and on to the remote
location. We call this “Respond, No Pass-Through”.
When Xon and Xoff commands are allowed to pass through the
modem, the computer or terminal at the remote site will receive these
commands, and depending on how it is configured, the computer or
terminal may respond to them also.
77
SERIES II INTELLIGENT DATA/FAX MODEMS
When two Series II Modems are connected in Normal mode (not using
error correction), Xon/Xoff can be used to control the flow of data
between the modems. Flow Control can be turned on or off with the
Normal Mode Modem Flow Control commands. When the modems
are connected in Reliable mode, a different method of modem Flow
Control is used, and the commands for Normal Mode Modem Flow
Control are ignored.
When you are using Speed Conversion in Normal Mode, you must
activate the modem’s Normal Mode Modem Flow Control. (Speed
Conversion is explained in Section 5.4.11.)
Send Xon/Xoff Characters #X
The #X phone interface command allows the Series II Modem to send
either a single or multiple Xoff characters at the modem's buffer full
level. When the Modem's buffer reaches it's "buffer full" level, the next
character received causes another Xoff to be sent for every character
subsequently received by the Modem.
The AT#X0 command (factory default setting) causes one Xoff to be
sent until the buffer reaches the Xon level. The AT#X1 command
causes an Xoff to be sent for every character received after the modem
reaches its buffer full level.
Hewlett-Packard ENQ/ACK Pacing &E9
If the Series II Modem is being used with Hewlett Packard (or similar)
equipment that employs ENQ/ACK pacing, the modem can be
configured to respond to ENQ/ACK commands, making it compatible
with HP systems. Doing so does not affect any other flow control or
pacing already configured in the modem.
When configured for ENQ/ACK, the ENQ (Control-E) and ACK
(Control-F) signals from the HP equipment will be accepted and re-
sponded to according to Hewlett-Packard protocol.
Normal Mode Modem Flow Control On &E11
When two Series II Modems are connected in Normal mode (not using
error correction), Xon/Xoff can be used to control the flow of data
between the modems. Flow Control can be turned on or off with the
Normal Mode Modem Flow Control commands. When the modems are
78
CHAPTER 5: Command Mode
connected in Reliable mode, a different method of modem flow control
is used, and the commands for Normal Mode Modem Flow Control are
ignored.
When you are using Speed Conversion in Normal Mode, you must
activate the modem’s Normal Mode Modem Flow Control. (Speed
Conversion is explained in Section 5.4.11.)
Terminal/Computer Initiated Pacing &E13
As mentioned earlier, the Series II Modem can initiate flow control by
issuing Xon/Xoff commands or toggling the CTS signal on the RS232C
interface. The modem can also be configured to react to similar com-
mands and signals from the computer or terminal to which it is
attached via the RS232C interface. We refer to the computer or
terminal initiated flow control as Pacing. When the modem is set for
Pacing On, the modem will respond to the terminal or computer
pacing. When the modem is set for Pacing Off, it will ignore pacing.
In order for the Series II Modem to be set for Pacing On, a modem-
initiated method of flow control must be previously selected. Once this
is done, the Modem will respond to either Xon/Xoff commands, or to
the toggling of the RTS (Request to Send) signal on Pin 4 of the
RS232C interface, depending on what you selected earlier as your
Modem-Initiated Flow Control method.
Maximum Block Size &BS
The maximum size of Reliable mode data blocks can be controlled with
the &BS command. MNP 3 sends blocks of 1 to 64 characters. MNP 4
and 5 typically send blocks of 1 to 256 characters and LAP-M typically
send 128 characters. For MNP Classes 4 and 5 and for LAP-M, reducing
the block size to 64 characters may give a smoother flow of data, and
better throughput on noisy phone lines. Using smaller block sizes over
good phone lines may cause a slight loss in throughput (speed).
AT&BS0 = Maximum transmit block size of 64 characters
AT&BS1 = Maximum transmit block size of 128 characters
(LAP-M) or 256 characters (MNP)
The factory default setting is &BS1.
79
SERIES II INTELLIGENT DATA/FAX MODEMS
Asynchronous Word Length Selection $EB (336 Only)
The Series II Modem 336 (MD1641A) has an 11-bit capacity when
operating asynchronously. The $EB command selects between 11-bit
and 10-bit operation. AT$EB1 enables 11-bit format (1 start bit, 8 data
bits, 1 parity bit, and 1 stop bit). AT$EB0 (default) enables 10-bit
format (1 start bit, 7 data bits, 1 parity bit, and 1 stop bit). $EB is
functional in both command and on-line mode. $EB0 automatically
detects parity when any AT command is issued.
AT$EB0 = Use 10-bit words
AT$EB1 = Use 11-bit words
The factory default setting is AT$EB0.
Parity Selection #P
The #P command enables the setting of parity. AT#P0 selects no parity.
AT#P1 selects odd parity. AT#P2 selects even parity and is the default
value. Note when setting up your data comm software, it is critical that
both your remote and local system's parity selection be set identically.
AT#P0 = no parity
AT#P1 = odd parity
AT#P2 = even parity
The factory default setting is AT#P2.
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CHAPTER 5: Command Mode
5.4.10 Compression, Error Correction, Flow
Control, Pass-Through and Pacing
Commands
The Series II Modem has a variety of commands to control its error
correction and data compression options. These additional commands
are listed below. (Remember to precede each command with the AT
characters.) Factory-default settings are marked with asterisks.
Normal/Auto-Reliable/Reliable Mode Commands:
&E0 =
&E1 =
&E2 =
Normal Mode
Auto-Reliable Mode*
Reliable Mode
Modem-Initiated Flow Control Commands:
&E3 =
&E4 =
&E5 =
Disables flow control (no flow control)
Hardware flow control (CTS on/off and RTS on/off)*
Xon/Xoff flow control
Xon/Xoff Pass-Through Commands:
&E6 =
&E7 =
Modem responds to Xon/Xoff characters, but does not
allow Xon/Xoff characters to pass through to remote
site.*
Modem responds to Xon/Xoff characters, and allows
them to pass through to remote site.
#X0 =
#X1 =
Selects single Xoff character until Xon level returns*
Selects multiple Xoff characters after buffer levels is
full.
*Factory-default setting.
81
SERIES II INTELLIGENT DATA/FAX MODEMS
Enq/Ack Pacing Commands:
&E8 =
&E9 =
Enq/Ack method of pacing off*
Enq/Ack method of pacing on
Normal Mode Modem Flow Control Commands:
&E10 =
&E11 =
Normal Mode Modem Flow Control off*
Normal Mode Modem Flow Control (Xon/Xoff) on
Computer-or Terminal-Initiated Flow Control (Pacing) Commands:
&E12 =
&E13 =
Pacing off*
Pacing on (either RTS on/off or Xon/Xoff depending on
the setting of &E4 or &E5).*
Data Compression Commands:
&E14 =
&E15 =
Data Compression disabled
Data Compression enabled*
*Factory-default setting.
5.4.11 Speed Conversion Commands
Speed conversion is a necessary part of data compression since data
must be presented to the modem faster than it can handle data, if data
compression is to be effective.
Speed conversion allows the Series II Modem to communicate at one
speed over the phone line, and at another speed at the RS232C
interface. The speed (also referred to as “data rate” or “baud rate”) can
be fixed at the RS232 interface independently of the baud rate of the
on-line transmissions.
In addition to data compression, another popular application for speed
conversion involves an auto-answer Series II Modem connected to a
computer that does not have autobaud capability. This means that the
82
CHAPTER 5: Command Mode
computer must be set at a fixed baud rate, regardless of whether the
modem is communicating over the phone line at 300, 1200, 2400, 9600,
14,400,19,200, 24,000, 28,800 or 33,600 bps. In this application, speed
conversion allows the modem to match its speed to that of the calling
modem, while at the same time communicating with the attached
computer through its RS232C port at a fixed baud rate, which can be
pre-selected at 300, 1200, 2400, 4800, 9600, 19,200, 38,400, 57,600 or
115,200 bps.
Speed Conversion $BA
When using speed conversion, you must set the modem so that it does
not adjust its speed at the RS232C serial port, even if the modem does
adjust its data rate. To turn Speed Conversion ON, enter the command
AT$BA0&W0 and hit RETURN.
To turn Speed Conversion OFF, enter AT$BA1&W0 and hit RETURN.
The modem will now match its RS232C speed to that of the computer,
and will adjust its speed to any changes in the computer’s speed in
Originate mode, or to the speed of the originating modem in Answer
mode. The speed at which the modem communicates over the phone
line will always be the same as the speed at which it communicates via its
RS232C serial port.
Modem Baud Rate $MB
The $MB command presets the Series II Modem’s transmission baud
rate for originate operations, (i.e., the speed of the modem’s transmis-
sions over the telephone lines when originating a call). With speed con-
version, this transmission speed can be a different baud rate than the
serial port speed.
When the Series II Modem receives (answers) a call from another
modem, it automatically switches its phone line transmission speed to
match the calling modem. However, if the Modem originates a call to
another modem that is unable to connect at the baud rate of the
Modem, it automatically drops to a lower baud rate in an attempt to
match the speed of that modem. For example, if the Modem is set for
19,200 baud and calls another modem that has a top speed of
2400 baud, it drops to 2400 baud.
83
SERIES II INTELLIGENT DATA/FAX MODEMS
The command to set the Modem Baud Rate is AT$MBn, where n can
be 300, 1200, 2400, 4800, 9600, 14,400,19,200, 28,800 or 33,600 bps as
listed below:
AT$MB300
=
=
=
=
=
=
=
=
=
300 bps
AT$MB1200
AT$MB2400
AT$MB4800
AT$MB9600
AT$MB14400
AT$MB19200
AT$MB28800
AT$MB33600
1200 bps
2400 bps
4800 bps
9600 bps
14400 bps
19200 bps
28800 bps
33600 bps
The factory default is 33600 bps.
Serial Port Baud Rate $SB
The $SB command presets the speed of the Series II Modem’s serial
(RS-232C) port, in both Originate and Answer modes. Speed
conversion allows you to set this serial port baud rate at a fixed speed
of up to 115,200 bps, regardless of the modem’s transmission speed
setting.
In order for this command to be effective, the modem’s Speed
Conversion feature must first be turned off with the $BA command.
When Baud Adjust is on, the Modem automatically adjusts its serial port
baud rate to match the speed of the computer or terminal it is connect-
ed to, as soon as it receives its first AT command. However, in many ap-
plications, such as automatic answer, the modem may not receive AT
commands, in which case it is very useful to be able to preset the serial
port baud rate with this $SB command.
In addition to setting the Modem’s serial port speed, this command also
sets the speed at which the modem issues Command mode responses.
The Modem will accept AT commands at any speed, regardless of the
speed preset by the $SB command. If the modem receives such a com-
mand at a speed that is different than the preset speed, the modem
switches its serial port baud rate to match the new AT command speed,
although the baud rate value stored by the $SB command remains the
84
CHAPTER 5: Command Mode
same. This provides you with a convenient way to switch the serial port
speed, and still make it easy to go back to the original speed automati-
cally the next time the modem is powered up or reset with an ATZ
command.
The command to set the Serial Port Baud Rate is AT$SBn, where n can
be 300, 1200, 2400, 4800, 9600, 19,200, 38,400, 57,600 or 115200 bps as
listed below:
AT$SB300
=
=
=
=
=
=
=
=
=
300 bps
AT$SB1200
AT$SB2400
AT$SB4800
AT$SB9600
AT$SB19200
AT$SB38400
AT$SB57600
AT$SB115200
1200 bps
2400 bps
4800 bps
9600 bps
19,200 bps
38,400 bps
57,600 bps
115,200 bps
The factory default is 115,200 bps.
Note: Some serial ports, particularly those in older PC-compatible
computers, may limit the performance of a higher speed modem like
the Series II Modem (see Chapter 3). The limiting factor is a circuit
called a Universal Asynchronous Receiver/Transmitter, or UART. All
data from your modem flows through it. 8250, 16450, and 16550 are
UARTs typically used in PC-compatible computers. The 8250 is
unreliable above 9,600 bps and the 16450 is unreliable above 19,200
bps. The 16550 UART, however, is reliable to at least 115,200 bps. With
V.42bis data compression enabled, the Modem can achieve throughputs
approaching 115.2K (depending on line quality and file content).
5.4.12 Immediate Action Commands
Help Screens $H
The Help command is designed to give you short explanations on how
to use each Series II Modem command. The Help command can be
quite useful if your manual is not handy and you are in the middle of a
communications session. Although the explanations are quite abbreviat-
ed compared to those in this manual, they should prove to be helpful
reminders when needed.
85
SERIES II INTELLIGENT DATA/FAX MODEMS
At the time of this writing, we have three screens of Help information
(Screen #1, #2 and #3), and more screens may be added in the future.
The Help commands are structured so that you can call up one of three
Help screens, as follows:
AT$H1 = Help Screen #1
AT$H2 = Help Screen #2
AT$H3 = Help Screen #3
Inquiry for Product Code I
Some systems or software packages automatically check the
“identification” of the modem with which they are communicating, by
using the I command. This “read” command lets the software to deter-
mine the type of modem with which it is communicating.
When ATI or ATI0 is entered, the Series II Modem responds with 247.
When ATI1 is entered, the modem responds with a three-digit code
indicating the firmware version number. When ATI2 is entered, the
modem responds with MD1641A if it’s a 336 model or MD1640A if
it’s a 336+ model.
Windows 95 Autodetect Inquiry I9
This read command permits a Windows 95 operating system to query
the Series II Modem's characteristics. When ATI9<CR> is entered, the
symbols BA 28800 FAX CT (336 model) or BL 28800 FAX CT (336+
model) are displayed; which indicates to the Windows 95 system that
your particular modem is a Series II Modem 336 or 336+, 28,800 bps, fax
Class 2 capable modem. With autodetect support in your Modem, your
PC can automatically allocate resources and configure it and other
devices. The Modem implements autodetect capability in the form of
a single .INF (Information) file that specifies AT Command mode and
Result Code "Registry Keys" that are specific to your Modem.
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CHAPTER 5: Command Mode
Listing Current Operating Parameters L5 L7
The L5 and L7 commands list the current operating parameters of your
modem. This information can be very useful when you are changing
communications software or when you are changing modem default
settings.
The command to list the Series II Modem’s current operating parame-
ters is ATL5 for the basic parameters. Entering ATL7 lists additional
parameters on the Modem.
Listing S-Register Values L6
Entering ATL6 lists the current values stored in the modem’s S-Register.
This information can be very useful if you wish to change S-Register
values. (Refer to Chapter 6 for more information on S-Registers).
Listing On-Line Diagnostics L8
The L8 command displays the current on-line CONNECT status of the
Series II Modem. This display can be printed and used as a modem
status report or as diagnostic information (such as when calling Tech
Support). To activate this command first type +++AT<CR>(on-line escape
command while maintaining command mode), then type ATL8. What then
displays on your monitor is your modem's current on-line condition
(e.g., Link Type, Line Speed, Serial Speed, Type of Error
Correction/Data Compression, Number of past Retrains, etc.).
See Figure 5-2 on the next page for a sample screen as displayed
through a Windows based terminal program.
87
SERIES II INTELLIGENT DATA/FAX MODEMS
File Edit Setup Perform Transfer Windows
Help
Feb29, 96 4:50pm MEWDEF
Connected to device
00:04:55
DCD
CTS
DSR
024
2A71
0213
ONLINE DIAGNOSTICS
L**IN*K*****T*Y**PE
LINE
SERIAL SPEED
ERROR CNTRL/COMPRESS
FALL
DATA
***********
28800/26400
V.34
SPEED
19200
LAPM
BACK/FORWARD LOCALLY ENABLED
FORMAT
ASYCHRONOUS
SYMBOL RATE(SYMETRIC) 3429/3429
CARRIER FREQUENCY
TRELLIS ENCODER
PRECODING
1959/1959
4D 16-STATE/4D 16-STATE
OFF/OFF
LINE
TYPE
DIAL UP
RECV. SIGNAL LEVEL
TRANS SIGNAL LEVEL
NUMBER OF RETRAINS
ROUND TRIP DELAY
-024.5 dBm
-011 dBm
000
0005 ms
-028.0/072.0 dBm
(MEANINGFUL IN V34 AND V32 MODE)
NEAR/FAR ECHO LEVEL
F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
F11
F12
Figure 5-2. On-line diagnostics information.
On or Off Hook H
You can make the Series II Modem hang up (go On Hook). Entering
ATH1<CR> brings the line Off Hook, just as if you picked up the
telephone set. You can hang up by entering ATH0 or ATH (the default
is 0 when no number is entered).
Escape Sequences- Entering Command Mode While Still
On-Line +++AT<CR>
It is possible to cause the Series II Modem to enter Command mode
after the modem has gone on-line with a remote modem without
disconnecting the call. This is done by entering an Escape Code. The
default Escape Code used by the Modem is three plus signs (+++)
followed by the letters A and T, up to sixty command characters (most
typically “H”, to hang up), and a RETURN. The number of command
characters allowed after +++ AT<CR> , is defined by S-Register S34.
S-Register S34 defaults to ten command characters.
88
CHAPTER 5: Command Mode
When this is done, the modem escapes to Command Mode, executes
the command (if any), and then remain in Command mode. For
example, to hang up the modem at the end of a call, enter +++ATH and
hit RETURN. There is no need to incorporate pauses before and after
the plus signs, as done in earlier modems.
BREAK AT<CR>
The Series II Modem provides an alternative Escape method, using a
Break signal as the Escape Code. The Break signal allows the start-stop
DTE (data terminal equipment) to signal the modem without loss of
character transparency. With this method, a BREAK signal is used
instead of the three plus signs. The BREAK is followed by the letters A
and T, up to 60 command characters, and RETURN. When this is done,
the modem executes that command, but remains in On-Line mode
unless the command was to hang up and/or reset the modem (an H or
Z), in which case the modem would be in the Command Mode after ex-
ecuting that command.
Escape Sequence Options - Entering Command Mode
While On-Line %E
As mentioned, the default escape sequence setting is for the modem to
respond to the +++ escape method. Optional settings are for the
modem to respond to the Break method, for the modem to respond to
either the +++ or the Break Methods, for the modem to ignore both
methods and not escape, for the modem to respond with no "OK" to
+++, and for the modem to respond with "OK" to +++. The %E com-
mand is used to select these options, as follows:
%E0
%E1
%E2
%E3
%E4*
%E5*
=
=
=
=
=
=
Modem Won’t Escape
+++ AT<CR> Method (default)
Break Method
Either +++ or Break Methods
No "OK" Response to +++
"OK" Response to +++
* The %E4 and %E5 commands enable or disable an "OK" response,
which is required by some software packages during an escape
sequence.
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SERIES II INTELLIGENT DATA/FAX MODEMS
Force Answer Mode A
You can force the Series II Modem into Answer mode with the modem’s
A command.
Entering ATA when in Command mode immediately brings your mo-
dem off-hook, out of Command mode and into On-Line Answer mode,
and causes it to transmit its carrier signal over the phone line. If no
responding carrier tone is received by your modem within forty-five
seconds (or some other time as determined by S-Register S7), your
modem stops transmitting its tone, hangs up, and goes back into
Command mode.
Exiting Command Mode, Going Back On-Line O
You can bring the Series II Modem out of Command mode and back
into On-Line mode by entering ATO (where O is the letter O, not the
number 0). In this case, the O command reverses what was done by
entering the Escape Code. The O command will bring the modem into
the same On-Line mode (Originate or Answer) that it was in prior to
going into Command mode.
5.4.13 Line Probe Commands
Before V.34 negotiation takes place, remote and local modems transfer
their functional capabilities using modulated calling and answering
tones; indicating the common capabilities of the modem at each end.
Once this is done, a probing signal is passed between the modems to
identify impairments in the telephone channel (e.g., Receive Signal
Strength vs. Frequency, Noise vs. Frequency and Signal to Noise Ratio
vs. Frequency). After receiving the results of the probing signal, the
modem receivers and transmitters begin with the lowest speed and
move up until reaching the highest speed at which they can exchange
data. All this occurs in about five seconds.
There are a number of Line Probe Commands. These commands are
configurable and can be stored to RAM (via AT&W0).
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CHAPTER1: Specifications
These commands are listed below.
Enable/Disable Reading of Line Probe Information Commands:
%DP0
Do not read Line Probe information from DSP during handshake
(Default).
%DP1
Read Line Probe information from DSP during handshake.
Format of Line Probe (Graph or Table) Commands:
%DF0
Data is displayed in Graph format. Y axis is shown in dBms (Default).
%DF1
Data is displayed in Table format. Numeric values are displayed
150 Hz to 3750 Hz in 75-Hz increments.
Immediate Action Line Probe Commands:
To activate these commands first type +++AT<CR> (on-line escape
command while maintaining command mode), then type the Command
prefixed by an AT.
&RP
This command initiates a retrain that makes the processor read Line
Probe information. Valid only when on-line in V.34 mode.
L9 = Displays Signal Strength information.
L10 = Displays Signal to Noise Ratio information (SNR).
L11 = Displays noise information.
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SERIES II INTELLIGENT DATA/FAX MODEMS
6. S-Registers
6.1
Introduction
Certain Command Mode configurations are stored in memory registers
called, S-Registers. The S command is used to assign a value to, and to
read the current value of an S-Register. To assign a value to an S-
Register, enter the letter S, followed by the S-Register number and an
equals sign (=), and then a decimal response to the message “ENTER
THE NEW VALUE IN DECIMAL FORMAT”. To read an S-Register value,
enter the letter S followed by the S-Register number and a question
mark (?), then hit RETURN. To verify that the S-Register value was
entered correctly, enter for example, ATS8? and hit RETURN. You
should receive a response of the assigned value given to that S-Register.
Refer to Section 6.2, Reading and Assigning S-Register Values.
S0
Number of Rings Until Modem Answers
Unit:
Rings
Range:
0-255
Default:
Description:
1
S0 defines the number of rings the modem waits
before answering an incoming call. The default
value is one ring (Decimal 1), which means that
the modem answers the call immediately after
the first ring. The maximum number of rings
that can be configured is 255. Setting the value
to zero (0) disables auto-answer completely.
S1
Rings Which Have Occurred
Unit:
Rings
Range:
0-255
Default:
Description:
0
S1 counts the number of rings that have
occurred. It is a “read” type of register and is
seldom, if ever, used in typical operation. Each
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CHAPTER 6: S-Registers
time an incoming ring signal is detected, S1
increases its value by one, up to a maximum of
255. If you set S1 to a value other than its default
value of zero, or if the value is increasing with
rings, this new value remains stored in S1 for
eight seconds after the last ring is counted, after
which time the value reverts to zero.
S2
Escape Code Character
Unit:
Decimal equivalents of ASCII characters
Range:
0-127
Default:
Description:
43 (+)
S2 defines the escape code character. The
default character is the plus (+) sign
(43 decimal), but may be set for any ASCII
character. Setting an S2 value greater than 127
results in no escape character, and therefore no
means of entering Command mode from On-
line mode without breaking the on-line
connection.
S3
Return Character
Unit:
Range:
Decimal equivalents of ASCII characters
0-127
Default:
Description:
13 (^M)
S3 defines the character recognized as Carriage
Return (RETURN) or “Enter”. S3 may be set for
any ASCII character.
S4
Line Feed Character
Unit:
Decimal equivalents of ASCII characters
Range:
0-127
Default:
Description:
10 (^J)
S4 defines the character recognized as Line
Feed. S4 may be set for any ASCII character.
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SERIES II INTELLIGENT DATA/FAX MODEMS
S5
Backspace Character
Unit:
Decimal equivalents of ASCII characters
Range:
0-127
Default:
Description:
8 (^H)
S5 defines the character recognized as
BACKSPACE. S5 may be set for any ASCII
character.
S6
Wait Time for Dial Tone
Unit:
Seconds
Range:
2-255
Default:
Description:
2
S6 sets the time the modem waits after the
RETURN key is pressed before executing a dial
command. The default setting is two seconds.
S7
Time for Carrier (Abort Timer)
Unit:
Seconds
Range:
1-255
Default:
Description:
45
S7 defines the Abort Timer (lack of carrier)
delay time. The default value is 45 seconds. This
means that, after dialing, the modem waits for a
carrier signal for up to 45 seconds and, if none is
detected, aborts the call. The maximum S7 value
is 255.
S8
Pause Time for Comma
Unit:
Seconds
Range:
0-255
Default:
Description:
2
S8 sets the length of the pause caused by a
comma inserted in a dialing command. The
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CHAPTER 6: S-Registers
default setting is two seconds. S8 may be set for
up to 255 seconds.
S8 also sets the time the modem waits before
retrying a call after detecting a busy signal. Some
computer systems need more than two seconds
to reset (in which case you should increase the
value of S8).
S9
Carrier Detect Response Time
Unit:
100-mSec intervals
Range:
1-255
Default:
Description:
6
S9 sets the time delay between when the modem
first detects a valid incoming carrier signal and
when the modem turns on its Carrier Detect
circuit. The default setting is 600 milliseconds
(six units of 100 mSec each). S9 may be set to a
maximum of 255 (25.5 seconds).
S10
Carrier Loss Disconnect Delay Time
Unit:
100-mSec intervals
Range:
0-255
Default:
Description:
7
S10 sets the time a carrier signal must be lost
before the modem disconnects. The default
setting is 700 mSec (seven units of 100 mSec
each). Maximum delay is 25.4 seconds (S10 set
to 254). Setting the S10 value to 255 causes the
modem to not disconnect with loss of carrier.
(This S-Register applies at speeds of 2400 bps
and less.)
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SERIES II INTELLIGENT DATA/FAX MODEMS
S11
Tone Dialing:Tone Spacing and Duration
Unit:
Milliseconds (mSec)
Range:
1-255
Default:
Description:
70
S11 sets the speed of tone dialing (spacing and
tone duration times). The default value is
70 mSec, meaning that each tone is on for
70 mSec with a 70 mSec pause between each.
The minimum S11 value allowed by most
telephone systems is 50 mSec. Very few
telephone systems can handle anything faster
than that. The maximum S11 value is 255 mSec.
S13
Remote Configuration Escape Character
Unit:
Decimal equivalents of ASCII characters
Range:
0-127
Default:
Description:
37 (%)
S13 defines the remote configuration escape
character (which becomes your modem’s
remote configuration character). The default is
three percent symbols (%%%). When the S13
character is entered three consecutive times
from a remotely connected site, your modem
responds with its Remote Configuration
procedure.
S15
Callback Time Delay
Unit:
Seconds
Range:
10-255
Default:
Description:
20
S15 defines the time delay between Callback
attempts after initial passwords have been
exchanged between modems. Refer to Chapter 7
for Callback Security information.
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CHAPTER 6: S-Registers
S16
Callback Attempts
Unit:
Range:
Default:
Description:
Attempts
1-255
4
S16 defines the number of attempts allowed
after initial passwords have been exchanged
between modems.
S17
Changing Break Time
Unit:
10-mSec intervals
Range:
0-250
Default:
Description:
250
S17 defines the break time (space) sent to the
local PC. The default is set for a 250-mSec
(2.5-second) break. The break time can be
changed in 10-mSec increments by increasing
or decreasing the value of S17.
S18
Automatic Leased Line Restoral (336+ Only)
Unit:
Minutes
Range:
10-255
Default:
Description:
30
When the Series II Modem 336+ (MD1640A) is
in dial backup mode, it periodically checks the
lease line to see if it is operational and tries to
restore the lease line if possible. S18 defines
how often attempts occur. The default of S18
is 30 minutes and can be set in one-minute
increments from 10 to 255 minutes. Setting the
S18 restoral under 10 minutes causes excessive
breaks in dial-up operation.
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SERIES II INTELLIGENT DATA/FAX MODEMS
S19
Dial-Back Timer (336+ Only)
Unit:
Minutes
Range:
0-255
Default:
Description:
1
In the Series II Modem 336+ (MD1640A), S19
is a timer that begins when the lease line goes
down. S19 specifies the duration of time the
modem attempts to reestablish the lease line
connection.
S24
PBX/CBX Disconnect Drop Time for DSR/CTS/CD
Unit:
50-mSec intervals
Range:
0-255
Default:
Description:
20
Some PBX and CBX phone systems require the
modem’s DSR, CTS, and/or CD signal(s) to
behave in a certain manner when calls are
disconnected. The Series II Modem’s &R, &S,
and &C commands cause the modem to drop
these signal(s) for a specified time period upon
disconnect, and then bring the signal(s) up
again. S24 defines the length of time that the
signals drop. The default setting of 20 results in
a one-second drop time, which is what most
PBX/CBX systems with this requirement need.
S25
DTR Dropout Time
Unit:
100-mSec intervals
Range:
0 (50 mSec), 1-255
Default:
Description:
0
S25 defines the amount of time that DTR must
be dropped before the modem disconnects.
Typically, a disconnect occurs when DTR is
dropped for 50 milliseconds or more. This
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CHAPTER 6: S-Registers
dropout time can be increased in 100-mSec
intervals, up to a maximum of 25.5 seconds
(S25 set to 255). The default S25 setting of zero
corresponds to a dropout time of 50 mSec.
All other possible settings (1 through 255)
correspond to their multiples of 100 mSec.
S26
Failed Password Attempts
Unit:
Failed attempts
Range:
0-255
Default:
Description:
0
S26 counts the number of times there has been
a failed password attempt. For example, if you
entered ATS26? and the message 003 were
displayed, it would mean that someone has
failed three times to gain access to your modem
using its password security system.
S29
Local Inactivity Timer
Unit:
Minutes
Range:
1-255
Default:
Description:
20
S29 defines the amount of idle time that can
elapse between AT commands after the SETUP
password has been entered. If this timer expires,
the LOGIN and SETUP passwords will have to
be re-entered. S29 only takes effect when the
modem has been sent a #DB1 command, which
secures the modem from local and remote con-
figuration or dialing (i.e., no AT commands can
be sent until the LOGIN and SETUP passwords
have been entered).
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SERIES II INTELLIGENT DATA/FAX MODEMS
S30
Inactivity Timer
Unit:
Minutes
Range:
0-255
Default:
Description:
0
S30 causes the modem to disconnect if no data is
transmitted or received for a specified time. This
timer runs during both Reliable and Normal
error correction connections. The timer restarts
any time a data character is passed through the
serial port (either sent or received). If noise on
the phone line causes an error to be received
during Normal mode, this also restarts the timer.
The inactivity timer is disabled by setting S30 to
zero, which is the factory default setting.
S32
Time Elapse for Escape Sequence
Unit:
Seconds
Range:
0-255
Default:
Description:
20
S32 sets the time period to validate the escape
sequence. If the time interval expires before
the escape sequence is employed (by hitting
RETURN), the escape sequence is aborted.
The default time is 20 seconds.
S34
Buffer Length of Command Mode...After On-line Escape
Sequence
Unit:
ASCII characters
Range:
0-60
Default:
Description:
10
If the number of characters after AT exceeds the
S34 buffer length value, the buffer is cleared and
the escape sequence is aborted.
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CHAPTER 6: S-Registers
S36
Time Between DTR Inactive and Modem Off-Hook
Unit:
Seconds
Range:
0-255
Default:
Description:
0
The DTR Busy-out feature uses S-Register S36 to
set the time between DTR inactive (low) and the
modem going off-hook. S36 can be set in one-
second intervals from 0 to 255 seconds. With the
default setting of S36=0, DTR Busy-Out is
disabled (i.e., DTR won't Busy-Out).
S37
Time Between DTR Active and Modem On-Hook
Unit:
Seconds
Range:
0-255
Default:
Description:
5
S37 sets the time between DTR being active and
the modem going on-hook (not busy). S37 will
only function in conjunction with S36.
S48
Program V.34bis Connect Speeds
Unit:
N/A
Range:
Default:
Description:
33, 31, 28, 26, 24, 21,19,16,14,12, 96, or 48
0
Defines which speed modem connects within
the scope of Enhanced V.34 mode (e.g., if S48 is
set to 26, the maximum connect speed will be
26.4K). This register compensates for line
conditions that have trouble supporting higher
Enhanced V.34 speeds (e.g., 33.6K, 31.2K, 28.8K,
26.4K, 24K...). The modem default is a value of
0, which indicates a connection attempt of
33.6K.
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SERIES II INTELLIGENT DATA/FAX MODEMS
6.2 Reading and Assigning S-Register Values
The S command is used to assign a value to, and to read the current
value of, an S-Register. To read an S-Register value, enter the letter S
followed by the S-register number and a question mark (?), then hit
RETURN. For example, entering ATS7? and hitting RETURN displays
the value of S-Register S7 in a 3-digit decimal form. The number 8
would appear as 008, the number 30 would appear as 030, and the
number 255 would appear as 255.
To assign a value to an S-Register, enter the letter S followed by the
S-Register number and an equals sign (=), and then a decimal response
to the message “ENTER THE NEW VALUE IN DECIMAL FORMAT”.
Convert all ASCII characters to their decimal equivalents before
entering them. S-Register decimal values range from 0-127 for ASCII
characters, or 0-255 for numeric values.
6.2.1 Examples of Assigning Values
1. Let’s say you wish to have longer pauses caused by the comma in a
dial command; five seconds instead of two. Entering ATS8=5
assigns 5 as the value for S-Register S8 (meaning the modem
pauses five seconds for a comma in a dial command).
2. In a second example, let’s say that you wish to configure the Series
II Modem to answer incoming calls after the 30th ring instead of
after the first ring. To configure S-Register S0 with a value of 30,
enter ATS0=30 and hit RETURN.
3. In a third example, let’s say you are calling long distance to
another country code, and it is taking a long time to connect. The
S-Register S7 (Abort Timer) setting of 45 seconds, is insufficient.
The abort timer times out and cancels the call before a connection
is made. To change the S7 value to 55 seconds, enter Command
mode, then enter ATS7=55 and hit RETURN. Now, after dialing,
the modem allows 10 more seconds for a carrier signal before
aborting the call. The additional 10 seconds should provide
enough time for international calls.
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CHAPTER 6: S-Registers
6.2.2 Examples of Reading Values
To verify that you entered the value correctly in the above examples,
enter ATS8? and hit RETURN in the first example, ATS0? in the
second, and ATS2? in the third example. You should receive the
response 005 in the first example, 030 in the second example, and 055
in the third example.
When configuring the S-Registers, it is a good practice to include the
verification read-entry in the same command line as the configuration
assignment-entry. In the three preceding examples, enter ATS8=5S8?,
ATS0=30S3?, and ATS7=55S7?.
6.3 AT Command and S-Register Summary
The vast majority of installations are similar, with the Series II Modem
being used to dial up a remote installation where the call is automati-
cally answered. Your Series II Modem has a default configuration to dial
another 33,600 bps modem that support error correction, data com-
pression and flow control. If the answering modem is not compatible,
the Modem can match protocols, provided the protocols are industry
standard (i.e., ITU or Bell) and not proprietary.
The &W command, used in conjunction with specific other AT
commands and S-Registers, can re-configure the Modem to conform to
a specific application. The command AT&W0 (or AT&W) causes the
modem to store its current parameters in its nonvolatile RAM. The
command also sets the modem upon power up, or when it is reset with
an ATZ command, the modem reads all of its configuration and S-
Register parameters from RAM, and not from the factory settings in
ROM (note that you may recall factory installed defaults by entering
AT&F8&W0). The &W command changes the configuration para-
meters stored in RAM that you specifically intend to alter. All other
default parameters remain unchanged.
The AT&W1 command sets the modem so that it does not store its
parameters in RAM, and on power up or when an ATZ command is
issued, parameters are read from the factory default settings in ROM.
Before using the &W command, you may want to view the modem's
current operating parameters. Use the ATL5, ATL6 and ATL7 com-
mands to display the current modem configuration.
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SERIES II INTELLIGENT DATA/FAX MODEMS
7. Callback Security
and Remote Configuration
7.1 Introduction
This chapter describes how the Series II Modem Callback and Remote
Configuration features operate. These features use a multilevel security
system, which involves the use of LOGIN Passwords, Setup Passwords
and Remote Escape Characters.
The primary level security code is the modem’s LOGIN Password. Once
this password is entered, other passwords can be used. For instance,
entering the LOGIN Password will allow you to enter the Setup Pass-
word, which, in turn, allows you to enter Callback Passwords and dial
back phone numbers. Callback Passwords tell your modem what dial
back phone number to call.
The Remote Escape Character is the key to using the Remote Configu-
ration feature. The Remote Escape Character lets you enter Command
mode via a remote call, so that you can enter AT commands just as if
you were locally connected. You must also enter your modem’s Setup
Password. The Remote Escape Character is contained in S-Register S13.
7.2 Callback Feature Description
The Callback feature protects your network from unauthorized access
and helps control long distance costs. By use of Callback Passwords and
dial back phone numbers, you can have your modem "dial back"
remote locations immediately after being called. A special command
(Enable Callback #DB) turns your modem into a Callback security
modem. The Callback Password/Phone number entry is protected
by two-level security (your modem's LOGIN Password and Set-Up
Password) that keeps unauthorized personnel from changing parame-
ters. When you first get your modem, you need to change both security
level codes to your unique settings.
The Callback Passwords and dial back phone numbers are in a special
Callback Password/dial back phone number memory (30 numbers
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CHAPTER 7: Callback Security and Remote Configuration
long). You use the modem's LOGIN Password and the Set-Up Password
plus special Callback commands to access this memory. The memory is
thirty numbers long and replaces your modem's normal phone number
memory.
Each number is 35 characters long and can contain commands as well
as phone numbers. You need to set up your modem with the numbers
and codes as part of the dial back initialization procedures. Your
modem will also remember if the incoming call was reliable or not,
and make the call back accordingly.
7.3 Remote Configuration Description
The Remote Configuration feature is a network management tool that
allows you to configure modems remotely. This means you could config-
ure modems anywhere in your network from one location without
having to visit the sites or rely on remote users to follow your instruc-
tions. With Remote Configuration, which is protected by two level
security, you can download new parameters, program new V.42
capabilities and implement new features. Remote Configuration also
makes troubleshooting a remote location a lot easier.
The way Remote Configuration works is that S-Register S13 has been set
up to contain the special Remote Configuration escape code. When
calling a Remote Configuration equipped modem, you enter the
proper Remote Escape code to enable entering your Set up Password.
After entering it, you can then execute AT commands as if you were
connected locally. If you set S-Register S13 to zero, Remote
Configuration is disabled.
7.3.1 Initial Setup Procedures for Callback
and Remote Configuration.
Your modem was shipped with a default LOGIN Password and Setup
Password (LOGIN=BLACK BOX and Set-up=MODEMSETUP) so that
you have access to the features used for configuring the modem.
Because the defaults are in the modem owner’s manual, and anyone
can find out what they are, you should change the codes as the first step
of your initialization procedure.
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SERIES II INTELLIGENT DATA/FAX MODEMS
Table 7-1. Modem LOGIN, Setup and Remote Escape Code
Procedures
To change your modem’s LOGIN Password and Setup Password:
Step
Procedure
Note: Passwords are upper/lower case sensitive. The case you enter
here is the case that must be used at Log-In.
1. Type AT#IBLACK BOX and hit RETURN. Your modem will
respond with:
OK (if the LOGIN Password is wrong, the modem’s response is
ERROR)
2. Type AT#SMODEMSETUP and hit RETURN. Your modem will re-
spond with the following:
OK (or ERROR if wrong Setup Password)
Note: At this point you can change the LOGIN Password and
Setup Password.
3. Type AT#I=xxxxxxxxxx (with any keyboard characters used,
minimum 6 maximum 10) and hit RETURN. Your modem
responds with:
OK
4. Type AT#S=yyyyyyyyyy (with keyboard characters used,
minimum 6 maximum 10) and hit RETURN. Your modem
responds with:
OK
To change your Remote Configuration feature status:
5. If you want Remote Configuration off, set S-Register S13 to 0
(zero). Refer to Chapter 6 for details on how to set S-Register
values.
6. If you want Remote Configuration on and wish to change the
Remote Escape Character, change the S-Register S13 value. If you
leave it at the default value, decimal 37 (% sign) will be your
modem’s remote escape character.
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CHAPTER 7: Callback Security and Remote Configuration
To turn your modem's Callback Security feature on and off:
7. If you want Callback Security with both remote and local password
security, enter AT#DB1 and hit RETURN. You must turn on
Callback Security to be able to enter dial back phone numbers.
8. If you want Callback Security on with just remote password security,
enter AT#DB2 and hit RETURN. You must turn on Callback
Security to be able to enter dial back phone numbers. If you want
to use your modem to call another modem that is also set for
Callback, you must enter AT#DB3 before you dial.
Note: This is for your modem if you are set for #DB1 or #DB2.
Once you have disconnected from that call, your modem will go
back to its original setting.
9. If you want Callback Security turned off, type AT#DB0 and hit
RETURN.
To set parity of the password/message prompt:
10. The parity default value for your modem is no parity (AT#P0). If
your modem's prompt messages use even parity, enter AT#P2 and
hit RETURN. For odd parity, enter AT#P1 and hit RETURN.
11. Enter the &W0 command and hit RETURN to store parameters
and S-Register values in RAM.
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SERIES II INTELLIGENT DATA/FAX MODEMS
Table 7-2. Callback Password and Dial Back Phone Number Entry
Procedures
Step
Procedure
1. Enter your modem's LOGIN Password (as selected in Table 7-1)
by entering the following:
AT#Ixxxxxxxxxx<CR> (xxxxxxxxxx from Table 7-1)
Enter your modem's Setup Password (as selected in Table 7-1)
by entering the following:
AT#Syyyyyyyyyy<CR>(yyyyyyyyyy from Table 7-1)
2. Enable the Callback Security feature by entering the following:
AT#DB2<CR>ÊorÊAT#DB1<CR>
The following message is displayed on your monitor:
Entering Callback Mode, current phone numbers will be erased. Do you
want to continue? (Y/N)
3. Enter a Y or N and hit RETURN.
Note: If this is your first time into Callback Mode, we recommend
answering Y to clear all previous Callback Passwords and phone
numbers from memory.
4. Enter individual Callback Passwords for each of 30 different phone
number memory locations as follows:
AT#CBN0xxxxxxxxxx<CR>
To enter Callback Password for the first location (a minimum 6
characters, up to a maximum of 10 characters must be used).
AT#CBN1xxxxxxxxxx<CR>
To enter Callback Password for the second location...etc (a
minimum 6 characters, up to a maximum of 10 characters must
be used).
Note: The first character of your first Callback Password must
be non-numeric.
5. Enter individual phone numbers for each of the 30 memory
locations as follows:
AT+ - DP...????N0 <CR> (number for location N0)
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CHAPTER 7: Callback Security and Remote Configuration
AT+ - DT...????N1 <CR> (number for location N1)...etc
Note: You must indicate within the command string that the
modem either Pulse dials (ATDP...) or Tone dials ATDT...).
The maximum length of the number is 35 characters. The number
may include commands as well as your number, so as to create
macro-type command numbers.
The + and/or - characters entered before the phone number are
optional. The + (Deposit Number) code allows a caller to enter the
number he or she wishes the Callback modem to call back when
the caller uses a particular password (Step 3 of Table 7-3). The -
character enables direct entry when the caller uses that correct
password (Step 3 of Table 7-3) without the Callback modem having
to return the call.
The ??? entry at the end of the phone number is optional and indi-
cates a subcode number to the main phone number for that
location. The ??? used to dial different extensions at the same basic
number. To use this optional feature, enter the number of ? marks
where indicated equal to the number of digits in the desired
extension number, (i.e., with a 4 digit extension enter ????). When
a caller uses that particular password (Step 3 of Table 7-3), he or
she then enters an extension number directly after the password,
with the same number of digits as the number of ? marks originally
entered. When calling back that particular number, your modem
will also dial the indicated extension number.
Note: To view Callback Passwords/Numbers, use the L Command.
6. To store changed parameters to memory, enter AT&W0 and hit
RETURN.
Note: If you have enabled Callback Security (#DB1 in step 2 of
Table 7-2), the Series II Modem will be secured locally. To gain
local access, you must again perform steps 7 and 8.
7. Enter your modem's LOGIN Password (as selected in Table 7-1)
by entering:
AT#Ixxxxxxxxxx<CR> (xxxxxxxxxx from Table 7-1)
8. Enter your modem's Setup Password (as selected in Table 7-1)
by entering:
AT#Syyyyyyyyyy<CR> (yyyyyyyyyy from Table 7-1)
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SERIES II INTELLIGENT DATA/FAX MODEMS
Table 7-3. Callback Operational Sequence Procedures
Perform the following steps when dialing into a dialback modem:
Step
Procedure
1. When called, the modem answers and after a slight delay, responds
with:
Password>
2. Enter your modem's LOGIN Password (Table 7-1) and hit
RETURN. If entered correctly, the modem responds with:
DB>
3. Enter the Callback Password corresponding to the phone number
you wish called back and hit RETURN (Callback Passwords and
phone numbers entered in Table 7-2). You can also use special
characters + and -. They must have been entered as part of the
Callback phone numbers in Step 5 of Table 7-2. If you use the -
character along with your password, the Callback modem will
connect directly without hanging-up and calling back. If you use
the + character along with your password, you can also enter a
phone number which you wish the Callback modem to dial after
hanging-up. The + and - characters must be entered after the Dial-
back password, (i.e., DB>xxxxxx+). This is also the point where
you enter an extension number if your Callback number used the
??? feature (Step 5 in Table 7-2).
You have three tries at each prompt to enter the information
properly, with an incorrect entry resulting in a password retry. You
must enter the requested information correctly within one minute
or the Callback modem will hang-up. When the information is
entered properly, the called modem will hang-up and after a
15-second delay, call you back. When your modem answers, the
dialback modem will respond with the following:
Password>
4. Enter the modem's LOGIN Password again (the same as in Step 1).
The Callback modem responds with:
CONNECT
You are now in Data Mode.
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CHAPTER 7: Callback Security and Remote Configuration
7.3.2 Remote Configuration Procedures
The procedures for using the Remote Configuration features are the
same whether or not a call originates from the remote modem. Once
the modem is on-line, perform the procedures in Table 7-4.
Table 7-4 Remote Configuration Operation Procedures
Step
Procedure
1. Remote Escape Configuration requires %%%AT<CR> to be sent
if the default value in S-Register S13 has not been changed.
The modem responds with:
1. - DATA Mode
2. - COMMAND Mode
2. You then select 1 or 2. With 1, the modem goes back into data
mode and with 2, the modem responds with the following:
Password>
3. Enter your Setup Password, and if the code is correct the modem
responds with:
OK
You can now use any AT commands of the modem being remotely
configured as if they were being entered locally. You cannot change
the setup of the LOGIN Password until you enter the proper
LOGIN Password.
4. When you are done entering AT commands and you want to exit,
type AT0 and hit RETURN. The modem responds with:
1. DATA Mode
2. COMMAND Mode
5. Enter a 1 to go back on-line with your computer, or enter 2
and the correct password to talk to your modem.
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SERIES II INTELLIGENT DATA/FAX MODEMS
7.4 Remote Configuration and Callback Security
AT Commands
The following AT commands are used with Remote Configuration
and Callback Security features.
Assign Passwords for Callback Phone Numbers #CBN
When you have callback security enabled for the Series II Modem,
anyone trying to connect with the modem will be required to furnish a
password. The #CBN command allows you to enter passwords for each
of the 30 memory locations used for callback security. The length of
each password can be up to 10 characters, but must be at least 6
characters. Any ASCII character can be used.
The format for this command is AT#CBNyyxxxxxxxx<CR> with
xxxxxxxx representing the password and yy being the memory
location (0-29). Each callback password (xxxxxxxx) must start with
a non-numeric character.
Callback Security Enable/Disable #DB
The purpose of this command is to enable or disable (default setting)
your modem's callback security option. Once this command is
executed, you modem will undergo some significant changes. For
example, the phone number memory locations (N0 through N9) will
be used for passwords and phone numbers. In other words, you will not
be able to dial from memory or use the DTR dialing feature.
You can turn on callback security by typing AT#DB1 or AT#DB2 and
pressing <CR>. If you want to engage both remote and local password
security, use the #DB1 command. This sets up the modem so you have
to provide passwords to dial into the modem and to dial out. For
remote password security only, use the #DB2 command. This allows the
local operator to dial out without providing the LOGIN and SETUP
passwords. Use #DB3 when calling another modem with callback
security active.
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CHAPTER 7: Callback Security and Remote Configuration
Change LOGIN Password #I
The default LOGIN password for your Series II Modem is "BLACK
BOX". If you choose to activate callback security, you should change the
LOGIN password using this command in the following format:
AT#Ixxxxxxxxxx<CR> (where xxxxxxxxxx is the current LOGIN
password)
Your modem will respond with "OK", indicating that you can enter the
new LOGIN password as follows:
AT#I=yyyyyyyyyy<CR>
You can select any combination of keyboard characters (upper/lower
case sensitive) between six and ten characters long.
Change SETUP Password #S
The default SETUP password for your Series II Modem is
"MODEMSETUP". If you choose to activate callback security, you should
change the SETUP password using this command in the following
format:
AT#Stttttttttt<CR> (where tttttttttt is the current SETUP password)
Your modem will respond with "OK", indicating that you can enter the
new SETUP password as follows:
AT#S=uuuuuuuuuu<CR>
You can select any combination of keyboard characters (upper/lower
case sensitive) between six and ten characters long.
Erase Callback Password #RCBNxx
This command erases the single callback password specified by xx
(0 through 29).
Erase Callback Phone Number #RDNxx
This command erases the single phone number specified by xx
(0 through 29).
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SERIES II INTELLIGENT DATA/FAX MODEMS
7.5 Remote Configuration/Callback Security
S-Registers
The following S-Registers are used with Remote Configuration and
Callback Security features.
Remote Configuration Character (S13)
S13 defines the Series II Modem remote configuration escape character.
When the S13 character is entered three consecutive times from a
remotely connected site, your modem responds to it with its Remote
Configuration procedure.
Units:
Decimal equivalents of ASCII characters
Range:
Default:
0-127
37 (% sign)
Callback Time Delay (S15)
S15 defines the time delay for Callback attempts after initial passwords
have been exchanged between modems.
Unit:
Range:
Default:
Seconds
10-255
20
Callback Attempts (S16)
S16 defines the number of Callback attempts after initial passwords
have been exchanged between modems.
Unit:
Range:
Default:
Attempts
1-255
4
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CHAPTER 7: Callback Security and Remote Configuration
Failed Password Attempts (S26)
S26 counts the number of times there has been a failed password
attempt. For example, if you entered ATS26? and the message 003
were displayed, that would mean someone had failed three times to
gain access to your modem using its password security system.
Units:
Failed attempts
Range:
Default:
0-255
0
Local Inactivity Timer (S29)
S29 defines the amount of idle time that can elapse between AT com-
mands after the SETUP password has been entered. If this timer
expires, the LOGIN and SETUP passwords will have to be re-entered.
S29 only takes effect when the modem has been sent a #DB1 command,
which secures the modem from local and remote configuration or
dialing (i.e., no AT commands can be sent until the LOGIN and SETUP
passwords have been entered).
Units:
Range:
Default:
Minutes
1-255
20
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SERIES II INTELLIGENT DATA/FAX MODEMS
8. Modem Testing
8.1 Introduction
Each time you power up the Series II Modem, it performs an automatic
self- test to ensure proper operation. The Modem also has four diag-
nostic test features: Local Analog Loopback, Digital Loopback
(remote/automatic), Digital Loopback (local/manual) and a
modem Back-to-Back test.
A loopback test involves entering data from your PC and looping that
data through the circuits of your modem and/or a remote modem.
When the loop has been completed, the original data entered should
match the data received back on your PCs monitor after the test.
The Local Analog Loopback Test allows you to verify that the modem’s
transmitter and receiver circuits are functioning properly.
The Digital Loopback Test (local/manual) allows you to verify that the
remote computer or terminal, the remote modem, serial ports, the
telephone line and the local modem are functioning properly.
The Digital Loopback Test (remote/automatic) allows you to verify that
the local computer or terminal, the two modems and the transmission
line between them are functioning properly.
The Back-to-Back test lets you connect two Series II Modems with a
back-to-back cable to verify proper modem operation.
In asynchronous mode, upon completion of testing, enter either
Escape Sequence, +++AT<CR> or <BREAK>AT<CR>.
Note: All loopback tests will operate at all speeds except 300 bps.
Disable error correction (&E0&W0<CR>) before engaging in
loopback tests (self-test and back-to-back test not affected).
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CHAPTER 8: Modem Testing
8.2 Local Analog Loopback Test/V.54 Loop 3
In this test, data from your computer or terminal is sent to your
modem's transmitter, converted into analog form, looped back to the
receiver, converted into digital form and then received back at your
monitor for verification. No connection to the phone line is required.
See Figure 8-1.
Computer or Terminal
Local Series II Modem
UUUUU
UUUUU
analog
digital
Type ATU0 or ATU1; hit ENTER
Figure 8-1. Local Analog Loopback Test
The test procedure is as follows:
1. Connect the modem to your computer. With your communication
software, set the desired baud rate.
2. Type ATU0 (or ATU) and hit ENTER. This places your modem in
Analog Loopback mode, in the Originate mode. The modem is
now out of the Command mode and in a pseudo On-Line mode.
3. Once you receive a connect message (if responses are enabled),
enter data from your keyboard. For this test, typing multiple upper
case "U" characters is a good way to send an alternating test pattern
of ones and zeros.
4. For a more complete test, you should also test the modem in
Answer mode. To do this, you must “escape” from Originate
mode by entering an Escape Sequence (+++AT<CR> or
<BREAK>AT<CR>) . Then type ATU1 and hit ENTER to place
the modem in Analog Loopback mode, in the Answer mode.
Then repeat step 3.
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SERIES II INTELLIGENT DATA/FAX MODEMS
5. When testing is completed, you may exit Answer mode by entering
an Escape Sequence (+++AT<CR> or <BREAK>AT<CR>), which
returns the modem to Command mode.
6. Your modem passes this test if the data entered from your keyboard
is the same as the data received on your monitor. If different data is
appearing on your monitor, your modem is probably causing the
problem, although it could also be your computer. If your modem
passes this test, but you are receiving errors while On-line, the
remote modem or the phone line could be at fault.
8.3 Digital LoopbackTest/V.54 Loop 2 (Local/Manual)
In this test, your modem must be On-Line with another modem that
can respond to a request for Digital Loopback, such as another Series II
Modem. The Digital Loopback Test is an on-line test that loops data
sent from one modem across the phone line to another modem, then
back to the first modem. See Figure 8-2.
There are two ways to put a modem into Digital Loopback mode.
1. Locally or Manually, described here in section 8.3.
2. Remotely or Automatically, see section 8.4.
Note: The Digital Loopback Tests can only be used with the
modem in Normal mode (error correction off).
Computer
or Terminal
Computer
or Terminal
Local Series II
Modem
Remote Series II
Modem
UUUUU
UUUUU
analog
digital
analog
digital
Type AT in Terminal mode; hit ENTER;
dial remote modem; establish On-line
mode; enter escape sequence;
type ATU3 and hit ENTER
Figure 8-2. Digital Loopback Test (local/manual)
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CHAPTER 8: Modem Testing
In this test the local modem is placed in Digital Loopback mode. Data
is entered and transmitted from the remote modem (which is not in
digital loopback mode), sent across the phone line to the local modem
and looped back to the remote modem.
The test procedure is as follows:
1. Go into Terminal mode. Type AT and hit ENTER; you should get
an OK message.
2. Dial the remote modem by entering the Dial command and the
phone number, to establish On-line mode.
3. Type the Escape Sequence (+++AT<CR> or <BREAK>AT<CR>)
which brings your modem into Command mode, while still main-
taining the pseudo On-line mode with the remote modem.
4. Type ATU3 from the local PC and hit ENTER. Once you receive an
OK message from your modem (if responses are enabled), the local
modem is placed in Digital Loopback mode.
5. Data is typed from the remote keyboard. For this test, typing
multiple upper case "U" characters is a good way to send an alter-
nating test pattern of ones and zeros. The data received by the local
modem will enter its analog receiver, be converted to digital data,
be reconverted into analog, and then looped through its
transmitter back to the remote modem. Your modem passes this
test if the data entered from the remote keyboard is the same as
the data received on the remote monitor.
6. When testing is complete, you may end the test by typing an Escape
Sequence (+++AT<CR> or <BREAK>AT<CR>) to bring your
modem into Command mode. The modem should respond with
an OK message. If you wish to stay On-line with the remote modem
for normal data transmission, type AT0 and hit ENTER. If you wish
to terminate the call, type ATH and hit ENTER to hang up.
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SERIES II INTELLIGENT DATA/FAX MODEMS
8.4 Digital Loopback Test/V.54 Loop 2
(Remote/Automatic)
In this test, your modem must be On-line with another modem set up
to respond to a request for Digital Loopback, such as another Series II
Modem. With the Modem, this ability to respond is controlled by the
&T command. AT&T4 enables the response to Digital Loopback Test
(remote/automatic). AT&T5 disables the response. The modem
defaults to disable on power up, so this must be changed on the remote
modem before the modem will respond to a request for the Digital
Loopback Test (remote/automatic).
Initiate the Digital Loopback Test (remote/automatic) with the ATU2
command which automatically places the remote modem in digital
loopback mode. Data from your computer or terminal are transmitted
through your modem, and over the phone line to the remote modem,
where they are then looped back to your modem. See Figure 8-3.
The test procedure is as follows:
1. Go into Terminal mode. Type AT and hit ENTER; you should get
an OK message.
2. Dial the remote modem by entering the Dial command and the
phone number, to establish On-line mode.
Note: The &T4 command must be set on the remote modem to
run this test.
Computer
or Terminal
Computer
or Terminal
Local Series II
Modem
Remote Series II
Modem
UUUUU
UUUUU
digital
analog
analog
digital
Type AT in Terminal mode; hit ENTER;
dial remote modem; establish On-line
mode; enter escape sequence; type ATU2
and hit ENTER
Figure 8-3. Digital Loopback Test (remote/automatic)
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CHAPTER 8: Modem Testing
3. Type the Escape Sequence (+++AT<CR> or <BREAK>AT<CR>)
which brings your modem into Command mode, while still main-
taining the connection with the remote modem.
4. Type ATU2 and hit ENTER. The local modem responds to this
command by transmitting an unscrambled marking signal, which
causes the remote modem to place itself in Digital Loopback mode.
Then the local modem exits Command mode and enters pseudo
On-line mode.
5. Type data from your keyboard. For this test, typing multiple upper
case "U" characters is a good way to send an alternating test pattern
of ones and zeros. The data received by the remote modem will
enter its analog receiver, be converted to digital data, be reconvert-
ed into analog, and then looped through its transmitter back to the
local modem. Your modem passes this test if the data entered from
the local keyboard is the same as the data received on your
monitor.
8.5 Back-to-Back Test
This test lets you connect two Series II Modems with an RJ11 cable to
verify proper operation. (See Figure 8-4A on the next page.) Using a
Series II Modem that is known to be operational, you can test a second
Modem that is suspect.
1. Plug the modular ends of an RJ11 cable into both Modems’ LEASE
jacks (336+ models) or LINE jacks (336 models).
2. Force DTR ON in both local and remote modems (Switch #1
DOWN).
3. Enter the command AT$SB9600$BA0&W0<CR> on both local
and remote modems. This sets the serial speed to 9600 bps. Make
sure that the terminal/computer is also set for 9600 bps.
4. Set both modems in Leased-Line mode (DIP-Switch # 10 DOWN).
5. Set one Series II Modem to Answer enabled (DIP-Switch #5 UP)
and the other Modem to Originate enabled (DIP-Switch #5
DOWN). Note that it does not matter which modem (local/remote)
is set to Answer/Originate—just so they are set opposite.
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SERIES II INTELLIGENT DATA/FAX MODEMS
6. Set DIP-Switch # 3 UP on both local and remote modems. This
changes the transmit level to -15dB and this change is necessary
to operate in back-to-back mode
7. Turn on both units and wait for carrier detect (CD).
8. Short out pins 2 and 3 on the RS-232C interface on the remote
modem (with a paper clip or some other metal device, for
example).
Remote sites:
Short Pins 2 and 3
of the RS-232
interface
PHONE
PSTN
LEASE
INTERFACE
PHONE
LINE
INTERFACE
ON
ON
OFF
OFF
VOLUME
POWER
VOLUME
POWER
PHONE
PSTN
LEASE
INTERFACE
PHONE
LINE
INTERFACE
ON
ON
OFF
OFF
VOLUME
POWER
VOLUME
POWER
Figure 8-4A. Back-to-Back Test Cabling
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CHAPTER 8: Modem Testing
9. Entered characters should echo back to the sending modem.
“Local”
modem
Back-to- “Remote”
back cable modem
DTE
Figure 8-4B. Back-to-Back Testing
8.6 Synchronous Mode Testing
The following tests must be run with your modem in Synchronous
mode (DIP Switch #12 in the Up (OPEN) position), DIP Switch #9
controls the modem’s Synchronous mode testing function. (Refer to
Chapter 9 for DIP Switch information.) The test procedures for
Synchronous mode are different from those for Asynchronous mode.
In Synchronous mode, you cannot access the modem’s AT commands.
With DIP Switch #9, you can perform either the Digital Loopback Test
(remote/automatic) or the Digital Loopback Test (local/manual) in
Synchronous mode, as described in the following sections. There is also
a Local Analog Loopback Test, documented in section 8.7.
8.7 Local Analog LoopbackTest (Synchronous Mode)
This test diagnoses the connection between your Series II Modem and
your computer or terminal. In Local Analog Loopback Test mode, data
entered at the local computer or terminal are sent through the local
modem’s transmit and receive circuits (much like entering an ATU or
ATU1 command in Asynchronous mode). You then compare the test
characters (multiple upper case “U” characters in Figure 8-5) on your
monitor with the characters you typed. If the characters don’t match,
check your computer’s COM port setting, then verify your
communication software’s configuration.
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SERIES II INTELLIGENT DATA/FAX MODEMS
To initiate the Local Analog Loopback Test, with the modem in
Synchronous mode:
1. Enter AT&M1U. This first switches your modem form asynchro-
nous to synchronous mode, and places it into the Analog Loop-
back/Originate mode. The modem is now out of the Command
mode and in the pseudo On-Line mode.
2. Once you receive a connect message (if responses are enabled), enter
data from your keyboard. For this test, typing multiple upper case
"U" characters is a good way to send an alternating test pattern of
ones and zeros.
3. For a more complete test, you should also test the modem in
Answer mode. To do this, Type the Escape Sequence (+++AT<CR>
or <BREAK>AT<CR>) which brings your modem into Command
mode, while still maintaining the connection. Then type
AT&M1U1 and hit ENTER to place the modem in Analog
Loopback mode, in the Answer mode. Then repeat step 2.
Local Series II Modem
Computer or
Terminal
UUUUU
UUUUU
analog
digital
Type ATU0 or ATU1; hit ENTER
Figure 8-5. Synchronous Mode Local Analog Loopback Test
8.8 Digital Loopback Test (Local/Manual)
(Synchronous Mode)
This test must be run when you have a data connection with another
modem. If a Local Analog Loopback Test resulted in errors, and this
test passes without errors, then the problem exists in your computer-to-
modem connection. In Digital Loopback Test (local/manual) mode,
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CHAPTER 8: Modem Testing
data passed from the remote modem’s transmit circuit are looped back
from the local modem and are received at the remote modem’s receive
circuit (multiple upper case “U” characters in Figure 8-6).
First make certain that you are set up for Synchronous operation by
placing DIP-Switch #12 in the UP position. To initiate the Digital
Loopback Test (local/manual), DIP-Switch #9 must be in the UP
position, and the Answer/Originate switch (front of the modem) must
be toggled to the UP position. Once you receive an OK message from
your modem (if responses are enabled), the local modem is placed in
Digital Loopback mode.
To exit the Digital Loopback Test (local/manual), toggle the
Answ/Orig switch to the Answer position.
Computer
Computer
or Terminal
or Terminal
Local Series II
Modem
Remote Series II
Modem
UUUUU
UUUUU
digital
analog
analog
digital
DIP switch #9
UP; Answ/Orig
switch toggled to
Answ position
when On-line
Figure 8-6. Synchronous Mode Digital Loopback Test
(local/manual)
8.9 Digital Loopback Test (Remote/Automatic)
(Synchronous Mode)
This test must be run when you have a data connection with another
modem. In this test, data is passed to the remote modem and is looped
back to the local modem (as if an ATU2 command was issued in
Asynchronous test mode), as shown in Figure 8-7. This lets you test the
local and remote modem’s transmit and receive circuits, as well as your
computer’s serial COM port and the phone lines. If the test results in a
mismatch of entered/received data (multiple upper case “U” characters
125
SERIES II INTELLIGENT DATA/FAX MODEMS
in Figure 8-6), the Local Analog Loopback Test should be performed
on both the remote and local modems. If that test is successful, the
problem may be the phone lines.
First make certain that you are set up for Synchronous operation by
placing DIP-Switch #12 in the UP position. To initiate the Digital
Loopback Test (remote/automatic), DIP-Switch #9 must be in the
DOWN position, and the Answer/Originate switch (front of the
modem) must be toggled to the UP position. Once you receive an OK
message from your modem (if responses are enabled), the local modem
is placed in Digital Loopback mode. To exit the Digital Loopback Test
(remote/automatic), toggle the front panel Answ/Orig switch to the
Answer position.
Computer or
Computer or
Terminal
Terminal
Local Series
II Modem
Local Series
II Modem
UUUUU
UUUUU
analog
digital
analog
digital
Type ATU0 or ATU1; hit ENTER
Figure 8-7. Synchronous Mode Digital Loopback Test
(remote/automatic)
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CHAPTER 9: DIP-Switch Settings
9. DIP-Switch Settings
9.1 Introduction
There are several DIP-Switch options on the Series II Modem’s printed
circuit (PC) board. The DIP-Switches are accessible through a cut-out
on the side of the modem. This chapter explains the Modem printed-
circuit board options. Sixteen DIP-Switch settings and the modem's
speaker volume control are explained in detail, including all default
settings.
Power switch
Power jack
FRONT
Speaker
RS/232/V.24
connector
LEDs
Volume knob
Line jack
16-position DIP switch
Phone jack
OPEN
OPEN
Voice/Data
switch with
Answ/Orig
REAR
1
2
3
4
5
6
7
8
9
10 11 12
13 14 15 16
Figure 9-1. Series II Modem 336 (MD1641A) PC Board
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SERIES II INTELLIGENT DATA/FAX MODEMS
FRONT
Power switch
Power jack
Speaker
RS/232/V.24
connector
LEDs
Volume knob
Leased-ine jack
Dialup jack
Phone jack
REAR
16-position DIP switch
OPEN
OPEN
Voice/Data
switch with
Answ/Orig
1
2
3
4
5
6
7
8
9
10 11 12
13 14 15 16
Figure 9-2. Series II Modem 336+ (MD1640A) PC Board
9.2 DIP-Switch Option Settings
Switch #1
Forced DTR -- "DTR"
(Asynchronous/Synchronous Mode/Leased Line/Dial-Up)
The Series II Modem must have a high DTR signal in order to operate.
DTR is provided to the modem by the terminal or computer to which it
is attached, through pin 20 of the RS-232C/V.24 interface. If your
terminal or computer is not providing DTR to the modem, you can
force the DTR signal high with DIP-Switch #1.
DTR function normally
DTR forced On
Factory Default Setting
=
=
=
Switch #1 UP
Switch #1 DOWN
UP
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CHAPTER 9: DIP-Switch Settings
Switch #2
Flow Control - &E4/&E5
(Asynchronous Mode/Leased Line/Dial-Up)
With Hardware Flow Control, the modem uses its RS-232C/V.24
interface to control the flow of data from the computer or terminal to
which it is attached. The CTS signal on Pin 5 of the RS-232C/V.24 is
brought low to stop the flow of data, and is brought high to restart it.
Place DIP-Switch #2 in the UP position to enable Hardware Flow
Control (&E4). Xon/Xoff Flow Control (&E5) is another flow control
method. Xon/Xoff characters in the data dictate the start and stop of
data flow from the computer or terminal. Place DIP-Switch #2 in the
DOWN position to select Xon/Xoff Flow Control.
Hardware Flow Control (&E4)
Xon/Xoff Flow Control (&E5)
Factory Default Setting
=
=
=
Switch #2 UP
Switch #2 DOWN
UP
Switch #2
SDLC/BSC Option
(Synchronous Mode/Leased Line/Dial-Up)
Synchronous Data Link Control (SDLC) and Binary Synchronous
Control (BSC) are two error correction protocols used in the IBM
Mainframe environment. Place DIP-Switch #2 in the UP position to
enable SDLC mode, and place DIP-Switch #2 in the DOWN position to
enable BSC mode.
SDLC Mode
BSC Mode
Factory Default Setting
=
=
=
Switch #2 UP
Switch #2 DOWN
UP
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SERIES II INTELLIGENT DATA/FAX MODEMS
Switch #3
Enable/Suppress Responses -- "Q"
(Asynchronous Mode/Dial-Up)
In some Asynchronous mode applications, you may want to suppress all
responses from the modem. Place DIP-Switch #3 in the DOWN position
to enable Result Code responses (Q0). Place DIP-Switch #3 in the UP
position, and answer mode is handled without responses and echo
turned off (Q2), but originate is still intelligent.
Enable Responses: Originate/Answer (Q0)
Suppress Responses: Answer (Q2)
Factory Default Setting
=
=
=
Switch #3 DOWN
Switch #3 UP
DOWN
Switch #3
dB Transmission Levels
(Asynchronous/Synchronous Mode/Leased Line)
DIP-Switch #3 adjusts dB transmission levels required by some phone
carriers. Place DIP-Switch #3 in the DOWN position to enable -9 dB
transmission. Place DIP-Switch #3 in the UP position to enable -15 dB
transmission.
-9dB Transmission
-15dB Transmission
Factory Default Setting
=
=
=
Switch #3 DOWN
Switch #3 UP
DOWN
Switch #4
AS/400 Mode
(Synchronous Mode/Leased Line/Dial-Up)
The Series II Modem can function in the IBM AS/400 environment
(appearing like an IBM 5853 modem). First, DIP-Switch #7 must be
placed in the UP position. This establishes an RTS/CTS condition
(state typical for an IBM 5853 modem in half-duplex mode). Next,
place DIP-Switch #4 in the DOWN position. This "spoofs" the Modem
into operating like an IBM 5853 modem in AS/400 applications. DIP-
Switch #4 in the UP position disables this function. Note that the
Modem must be in Command mode to allow AS/400 mode (DIP-Switch
#8 DOWN); and in Synchronous mode (DIP-Switch #12 UP).
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CHAPTER 9: DIP-Switch Settings
AS/400 Mode Enabled
AS/400 Mode Disabled
Factory Default Setting
=
=
=
Switch #4 DOWN
Switch #4 UP
UP
Switch #4
Unix UUCP Spoofing
(Asynchronous Mode/Leased Line/Dial-Up)
The Series II Modem can be configured for use with Unix equipment
which employs ACK flow control to monitor data integrity. The Modem
can do "UUCP spoofing", where the modem is able to generate ACKs at
the DTE interface. Data then is transmitted more time-efficiently,
because the delay of waiting for data to be received then waiting for the
ACK to be returned at the remote end, is eliminated. Placing DIP-
Switch #4 in the DOWN position enables UUCP spoofing.
UUCP Spoofing Enabled = Switch #4 DOWN
UUCP Spoofing Disabled = Switch #4 UP
Factory Default Setting
=
UP
Switch #5
Enable/Disable Auto-Answer - "Ans"
(Asynchronous Mode/Synchronous Mode/Dial-Up)
In some originate-only applications, you may wish to disable the Series
II Modem's automatic answering capabilities. This may be true if you
have a telephone set attached to a modem and wish to receive voice
calls that you yourself would answer instead of the modem. Place DIP-
Switch #5 in the UP position to enable Auto-Answer. Place DIP-Switch
#5 in the DOWN position to disable Auto-Answer.
Auto-Answer Enabled
Auto-Answer Disabled
Factory Default Setting
=
=
=
Switch #5 UP
Switch #5 DOWN
UP
Switch #5
Originate/Answer Mode
(Asynchronous/Synchronous Mode/Leased Line)
The Series II Modem functions in either Originate mode or Answer
mode. Place DIP-Switch #5 in the DOWN position to enable Originate
mode. Place DIP-Switch #5 in the UP position to enable Answer mode.
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SERIES II INTELLIGENT DATA/FAX MODEMS
Originate Mode Enabled = Switch #5 DOWN
Answer Mode Enabled
Factory Default Setting
=
=
Switch #5 UP
UP)
Switch #6
Maximum Throughput Setting
(Asynchronous Mode/Leased Line/Dial-Up)
Some applications require you to dial into services with maximum
throughput on, and other applications where maximum throughput
must be off (i.e., service not supporting error correction, or the V.42
handshake interferes with logon sequence). DIP-Switch #6 is used for
switching between these two modes. This DIP-Switch controls three
important parameters (error correction, speed conversion and serial
port speed), which in effect enables or disables maximum throughput.
Maximum Throughput Enabled = Switch #6 UP
Maximum Throughput Disabled = Switch #6 DOWN
Factory Default Setting
=
UP
Switch #6
Slave Clocking
(Synchronous Mode/Leased Line/Dial-Up)
In Synchronous mode, DIP-Switch #6 controls the option of having
timing controlled by the receive clock. The originate modem, in effect,
adjusts to the answer (remote) modem. Place DIP-Switch #6 in the
DOWN position to enable Slave Clocking. Place DIP-Switch #6 in the
UP position to disable Slave Clocking.
Slave Clocking Enabled
Slave Clocking Disabled
Factory Default Setting
=
=
=
Switch #6 DOWN
Switch #6 UP
UP
Switch #7
Request To Send Forced - "RTS"
(Asynchronous/Synchronous Mode/Leased Line/Dial-Up)
If your computer or terminal uses RTS-CTS protocol (typically used in
some synchronous applications, but also if using hardware pacing for
V.42 error correction or speed conversion), you may want to set RTS to
function independently of CTS (DIP-Switch #7 UP). For most
132
CHAPTER 9: DIP-Switch Settings
applications, especially asynchronous, this switch should be set so that
RTS is forced On (DIP-Switch #7 DOWN)
RTS functions Normally
RTS forced On
Factory Default Setting
=
=
=
Switch #7 UP
Switch #7 DOWN
DOWN
Switch #8
Enable/Disable Command Mode -- "Com"
(Asynchronous/Synchronous Mode/Leased/Dial-Up)
In some applications you may want to disable the Series II Modem's
Command mode so that the modem does not recognize or react to AT
or V.25bis commands. This may be true in strictly auto-answer
applications where no call origination is required. Place DIP-Switch #8
in the DOWN position to enable Command mode. Place DIP-Switch #8
in the UP position to disable Command mode. The factory default
setting is Command mode enabled.
Disable Command Mode
Enable Command Mode
Factory Default Setting
=
=
=
Switch #8 UP
Switch #8 DOWN
DOWN
Switch #9
Digital Loopback Test
(Asynchronous/Synchronous Mode/Leased Line/Dial-Up)
When in Synchronous mode, this switch controls both Local Digital
Loop and Remote Digital Loop tests while on-line. When the
Voice/Data switch is toggled to the Answer mode position (UP) and
DIP-Switch #9 is in the UP position, the Series II Modem performs the
Local Digital Loopback test. When DIP-Switch #9 is DOWN and the
Voice/Data switch is toggled to Answer mode position (UP), the
Series II Modem performs the Remote Digital Loopback test.
Local Digital Loopback Test
Remote Digital Loopback Test
Factory Default Setting
=
=
=
Switch #9 UP
Switch #9 DOWN
DOWN
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SERIES II INTELLIGENT DATA/FAX MODEMS
Switch #10
Leased Line/Dial-Up Operation -- "DDD"
(Asynchronous/Synchronous Mode/Leased Line/Dial-Up)
The Series II Modem operates in either leased-line or dial-up modes.
This switch controls leased-line/dial-up operation. Place DIP-Switch #10
in the UP position for Dial-Up operation. Place DIP-Switch #10 in the
DOWN position for Leased-Line operation
Dial-Up Operation
Leased Line Operation
Factory Default Setting
=
=
=
Switch #10 UP
Switch #10 DOWN
UP
Switch #11
"AT" Responses/Series II Responses
(Asynchronous Mode/Leased line/Dial-Up)
In Asynchronous mode, you can set the Series II Modem to respond
with Result Codes according to the “Series II" command response set
(Switch #11 in the DOWN position), or to “AT" command response set
(Switch #11 in the UP position). The &Q command performs the same
function (choosing AT or Series II Result Codes), and is explained
further in section 5.3 of this manual.
“AT" Responses (&Q1)
“Series II" Responses (&Q0)
Factory Default Setting
=
=
=
Switch #11 UP
Switch #11 DOWN
DOWN
Switch #11
Internal/External Clocking
(Synchronous Mode/Leased Line/Dial-Up)
In Synchronous mode, the transmit clock can be supplied by the DTE
on pin 24 of the RS-232C/V.24 interface by placing DIP-Switch #11 UP.
Place DIP-Switch #11 in the DOWN position to enable DCE to control
clocking (internal clock via pins 15 and 17 of the RS-232/V.24
interface).
External Clock (pin 24)
Internal Clock (pins 15/17)
Factory Default Setting
=
Switch #11 UP
=
Switch #11 DOWN
=
DOWN
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CHAPTER 9: DIP-Switch Settings
Switch #12
Asynchronous/Synchronous Operation -- "Sync"
(Asynchronous/Synchronous Mode/Leased Line/Dial-Up)
The Series II Modem can operate in either Asynchronous mode or
Synchronous mode. In Synchronous mode, start and stop bits are
eliminated. The modem's internal clock circuits on the RS-232C/V.24
pins 15 and 17 are activated. The Series II Modem's Command mode is
not accessible in Synchronous mode. This switch is a means to alternate
and to access either mode. In Synchronous mode, you may want to set
the RTS forcing and CTS forcing DIP-Switches so that both of signals
act normally (not forced on).
Synchronous Operation
Asynchronous Operation
Factory Default Setting
=
=
=
Switch #12 UP
Switch #12 DOWN
DOWN
Switches #13 and #14
Speed Switches
(Synchronous Mode/Leased Line)
DIP-Switches #13 and #14 are used to set the Series II Modem’s data
transmission rate. Switches #13 and #14 are used in combination,
typically in leased-line and call origination applications. Note that the
modem baud rate command ($MB33600) overrides the setting of these
speed selection switches (DIP switches #13 and #14).
28800 bps Operation
19200 bps Operation
14400 bps Operation
9600 bps Operation
Factory Default Setting
=
=
=
=
=
Switch #13 UP and Switch #14 UP
Switch #13 DN and Switch #14 UP
Switch #13 UP and Switch #14 DN
Switch #13 DN and Switch #14 DN
Switch #13 UP and Switch #14 UP
Switch #15
Carrier Detect/DSR Forcing -- "DSR"
(Asynchronous/Synchronous Mode/Dial-Up/Leased Line)
Some terminals react in unusual ways to the toggling of the Carrier
Detect (CD - RS-232C/V.24 pin 6) signals. The most common symptom
is that the modem does not respond to commands, or does not echo
characters. In these cases, it is advisable to force these two signals On in
order for the terminal to communicate properly with the modem in
135
SERIES II INTELLIGENT DATA/FAX MODEMS
Command mode. This is done by setting DIP-Switch #15 DOWN. With
DIP-Switch #15 in the UP position, both CD and DSR will be either on
or off, depending on the On-Line status.
CD and DSR normal
CD and DSR forced On
Factory Default Setting
=
=
=
Switch #15 UP
Switch #15 DOWN
UP
Switch #16
2 Wire/4 Wire Operation
(Asynchronous/Synchronous Mode)
The Series II Modem works over either 2-wire or 4-wire leased lines. To
select 4-wire operation, place Switch #16 DOWN (Default); and to select
2-wire operation, place Switch #16 UP.
2-Wire Leased Line
4-Wire Leased Line
Factory Default Setting
=
=
=
Switch #16 UP
Switch #16 DOWN
DOWN
9.3 Speaker Volume Control
You can adjust the volume of the Series II Modem’s phone-line monitor
speaker with a volume control knob, located on the back of the modem
next to the RS232C connector (see Figure 9-1 for location). Turn the
knob clockwise to increase the modem's volume and counterclockwise
to decrease speaker volume. See Speaker Control Command (M) in
Section 5.4.6.
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CHAPTER 9: DIP-Switch Settings
9.4 Recording Option Configurations
This section lets you record any changes you may have made to the DIP-
Switch settings. Circle the appropriate setting and record the effect for
future reference.
DIP-Switches
Sw.
Function
PositionEffect
#1 Force DTR/DTR from Interface* UP*
DOWN
UP*
#2 Flow Control &E4*/&E5
(Async/Dial-Up/Leased Line)
DOWN
#2 SDLC*/BSC (Sync)
UP*
DOWN
#3 Result Codes Enable*/Disable
(Async/Dial-up)
UP
DOWN*
#3 DbM Transmit -9dB*/-15dB
(Async/Sync/Lease-Line)
UP
DOWN*
#4 UUCP Enable/Disable*
(Async/Dial-Up/Leased Line)
UP*
DOWN
#4 AS/400 Enable/Disable*
(Sync/Dial-Up/Leased line)
UP*
DOWN
#5 Auto-Answer Enable*/Disable
(Async/Sync/Dial-Up)
UP*
DOWN
#5 Answer*/Originate
(Async/Sync/Leased Line)
DOWN
UP*
#6 Max-Thru Enable*/Disable
(Async/Dial-Up/Leased)
UP*
DOWN
#6 Slave Clock Enable/Disable*
(Sync/Dial-Up/Leased)
UP*
DOWN
#7 RTS/Normal/Forced*
(Sync/Async/Dial/Leased)
* Factory Default Setting
UP
DOWN*
137
SERIES II INTELLIGENT DATA/FAX MODEMS
Sw. Function
Position Effect
#8 Command Mode Enabled*
(Sync/Async/Dial/Leased)
UP
DOWN*
#9 Local/Remote* LoopBack
(Async/Sync/Dial/Leased)
UP
DOWN*
#10 Dial-Up*/Leased-Line
UP*
DOWN
#11 “AT" vs. “Series II" Result Codes*
UP
(Asynchronous)
DOWN*
#11 Internal*/External Clocking
(Synchronous)
UP
DOWN*
#12 Sync/Async Mode*
UP
DOWN*
* Factory Default Setting
DIP Switches #13-16
SWITCH
#13/#14
#13/#14
#13/#14
#13/#14
CONDITION
UP/UP*
EFFECT
28.8 K bps Operation
19.2 K bps Operation
14.4 K bps Operation
DOWN/UP
UP/DOWN
DOWN/DOWN 9600 bps Operation
Note: Modem baud rate commands such as $MB33600 override the
setting of these speed selection switches (DIP switches #13 and #14).
#15
#15
#16
#16
UP*
CD/DSR from Interface
CD/DSR Forced On
2-Wire Leased Line
4-Wire Leased Line
DOWN
UP
DOWN*
*Standard Factory Default Setting
138
APPENDIX A: Troubleshooting
Appendixes
Appendix A - Troubleshooting
Your Series II Modem was thoroughly tested at the factory before it was
shipped. If you are unable to make a successful connection or if you
experience data loss or garbled characters during your connection, it is
possible that the modem is defective. However, it is more likely that the
source of your problem lies elsewhere. Problems you may encounter
include the following:
•
•
•
•
•
•
•
•
•
None of the LEDs light when the modem is on.
The modem does not respond to commands.
The modem dials but is unable to make a connection.
The modem disconnects while on-line.
The modem cannot connect when answering.
File transfer is slower than it should be.
I am losing data.
I am getting garbage characters on the monitor.
I can’t run my fax and communications software at the same time.
If you experience problems, please check the possibilities in Section A.1
before calling Tech Support (see Section A.2).
A.1 Possible Causes and Solutions
None of the LEDs Light When the Modem Is On
When you turn on the Series II Modem, the LED indicators on the
front panel should flash briefly as the modem runs a self-test. If the
LEDs remain off, the modem is probably not receiving power.
•
•
•
Make sure the modem’s power switch is on, especially if you nor-
mally turn on the modem by turning on a power strip.
If the power supply is plugged into a power strip, make sure the
power strip is plugged in and its power switch is on.
Make sure the power supply module is firmly connected to the
modem and to the wall outlet or power strip.
139
SERIES II INTELLIGENT DATA/FAX MODEMS
•
If the power strip is on and the modem switch is on, try moving the
modem power supply to another outlet on the power strip.
•
•
Test that the outlet is live by plugging a lamp into it.
The modem or power supply may be defective. If you have another
Series II Modem, try swapping modems. If the problem goes away,
the first modem or power supply may be defective. Call Tech
Support for assistance.
CAUTION: Do not under any circumstances replace the power supply
module with one designed for another product, as it may damage the
modem and void your warranty.
The Modem Does Not Respond to Commands
•
Make sure the modem is plugged in and turned on. (See “None of
the LEDs Light When the Modem Is On.”)
•
Make sure you are issuing the modem commands from the data
communications software, either manually in terminal mode or au-
tomatically by configuring the software. (You cannot send com-
mands to the modem from the DOS prompt.)
•
Make sure you are in terminal mode in your data communications
program, then type AT and press ENTER. If you get an OK re-
sponse, your connections are good and the problem likely is in
your phone book entry or session settings.
•
•
Try resetting your modem by turning it off and on. Make sure there
is a reset command (&F) in your initialization string, or your
modem may not initialize correctly.
If you don’t get an OK, the problem may still be in the communica-
tions software. Make sure you have done whatever is necessary in
your software to make a port connection. Not all communications
programs connect to the COM port automatically. Some connect
when the software loads and remain connected until the program
terminates. Others can disconnect without exiting the program
(make sure the Connect icon looks plugged in). If the terminal
reports that it cannot make a connection, yet the modem’s TR indi-
cator is on, click on the Window menu to see if more than one ter-
minal is open. The modem’s TR indicator shows that the software
has made a connection with the modem through the COM port.
140
APPENDIX A: Troubleshooting
•
•
Your communications software settings may not match the physical
port the modem is connected to. The serial cable may be plugged
into the wrong connector—check your computer documentation
to make sure. Or you may have selected a COM port in your
software other than the one the modem is physically connected
to—compare the settings in your software to the physical
connection.
If the modem is on, the cable is plugged into the correct port, the
communications software is configured correctly, and you still
don’t get an OK, the fault may be in the serial cable. Make sure it is
firmly connected at both ends.
•
•
Is this the first time you have used the cable? If so, it may not be
correct. Check the cable description on the packaging to make
sure the cable is the right one for your computer.
Peripheral expansion cards, such as bus mouse and sound cards,
may include a serial port pre-configured as COM1 or COM2. The
extra serial port, or the card itself, may use the same COM port,
memory address, or interrupt request (IRQ) as your communica-
tions port. Be sure to disable any unused ports.
To look for address or IRQ conflicts if you use Windows 3.1x, select
File, Run in Program Manager, type MSD, and press ENTER. Then
select Mouse, COM Ports, and IRQ Status and note the addresses
and IRQs that are in use. If you find an IRQ conflict, note which
IRQs are not being used, then change one of the conflicting
devices to use one of the unused IRQs. If you find an address
conflict, change the address of one of the conflicting devices.
To change a port address or IRQ in Windows 3.1x, double-click the
Control Panel icon, then the Ports icon. Click on the port you want
to change, click Settings, click Advanced, and select the new port
address and/or interrupt. If you wish to use COM3 or COM4, note
that COM3 shares an IRQ with COM1, as does COM4 with COM2,
so you should change their IRQs to unused ones, if possible.
If you use Windows 95, right-click on My Computer, select Proper-
ties from the menu, click on the Device Manager tab, double-click
on Ports, then double-click on the Communications Port your
modem is connected to. In the port’s Properties sheet, click on the
Resources tab to see the port’s Input/Output range and Interrupt
Request. If another device is using the same address range or IRQ,
141
SERIES II INTELLIGENT DATA/FAX MODEMS
it will appear in the Conflicting Device List. Uncheck Use
Automatic Settings to change the port’s settings so they do not
conflict with the other device, or select the port the conflicting
device is on and change it instead. If you need to open your
computer to change switches or jumpers on the conflicting device;
refer to the device’s documentation.
•
•
The serial port may be defective. If you have another serial port,
install the modem on it, change the COM port setting in your soft-
ware, and try again.
The modem may be defective. If you have another Series II
Modem, try swapping modems. If the problem goes away, the first
modem is possibly defective. Call Tech Support for assistance (see
Section A.2).
The Modem Dials But Cannot Make a Connection
There can be several reasons the Series II Modem fails to make a con-
nection. Possibilities include
•
•
•
•
•
•
•
lack of a physical connection to the telephone line.
a wrong dial tone.
a busy signal.
a wrong number.
no modem at the other end.
a faulty modem, computer, or software at the other end.
incompatibility between modems.
You can narrow the list of possibilities by using extended result codes.
To enable them, enter ATV1X4 and press ENTER while in terminal
mode, or include V1X4 in the modem’s initialization string. When you
dial again, the modem will report the call’s progress.
•
If the modem reports NO DIALTONE, check that the modem’s
telephone line cable is connected to both the modem’s LINE jack
(not the PHONE jack) and the telephone wall jack. If the cable
looks secure, try replacing it. If that doesn’t work, the problem may
be in your building’s telephone installation. To test the building
installation, plug a telephone into your modem’s telephone wall
jack and listen for a dial tone. If you hear a dial tone, your modem
may be installed behind a company phone system (PBX) with an
142
APPENDIX A: Troubleshooting
internal dial tone that sounds different from the normal dial tone.
In that case, the modem may not recognize the dial tone and may
treat it as an error. Check your PBX manual to see if you can
change the internal dial tone; if you can’t, change your modem’s
initialization string to replace X4 with X3, which will cause the
modem to ignore dial tones.
•
If the modem reports BUSY, the other number may be busy, in
which case you should try again later, or it may indicate that you
have failed to add a 9, prefix to the phone number if you must dial
9 for an outside line.
If you must dial 9 to get an outside line, the easiest way to dial it au-
tomatically is to include it in the modem’s dial prefix, e.g., ATDT9,.
Note the comma, which inserts a pause before the number is
dialed. By inserting 9, into the dial prefix, you do not have to in-
clude it in each directory entry in the terminal.
To change the dial prefix in Windows Terminal, select Settings,
Modem Commands. To change it in Windows 95 HyperTerminal,
select Call, Connect from the menu bar, click Dialing Properties,
and type 9 in the local and long distance boxes in How I Dial from
This Location.
•
•
If the modem reports NO ANSWER, the other system has failed to
go off-hook, or you might have dialed a wrong number. Check the
number.
If the modem reports NO CARRIER, the phone was answered at the
other end, but no connection was made. You might have dialed a
wrong number, and a person answered instead of a computer, or
you might have dialed the correct number but the other computer
or software was turned off or faulty. Check the number and try
again, or try calling another system to make sure your modem is
working. Also, try calling the number on your telephone. If you
hear harsh sounds, then another modem is answering the call, and
the modems may be having problems negotiating because of
modem incompatibilities or line noise. Try connecting at a lower
speed.
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SERIES II INTELLIGENT DATA/FAX MODEMS
The Modem Disconnects While On-line
•
If you have call waiting on the same phone line as your modem, it
may interrupt your connection when someone tries to call you. If
you have call waiting, disable it before each call. In most telephone
areas, you can disable call waiting by preceding the telephone num-
ber with *70 (check with your local telephone company).
You can automatically disable call waiting by including the
disabling code in the modem’s dial prefix (e.g., ATDT*70,—note
the comma, which inserts a pause before the number is dialed). To
change the dial prefix in Windows Terminal, select Settings,
Modem Commands. To change it in Windows 95 HyperTerminal,
select Call, Connect from the menu bar, click Dialing Properties,
check this location has Call Waiting, and select the correct code for
your phone service.
•
If you have extension phones on the same line as your modem, you
or someone else can interrupt the connection by picking up anoth-
er phone. If this is a frequent problem, disconnect the extension
phones before using the modem, or install another phone line es-
pecially for the modem.
•
•
Check for loose connections between the modem and the
computer, the telephone jack, and AC power.
You may have had a poor connection because of line conditions or
the problem may have originated on the other end of the line. Try
again.
•
If you were on-line with a BBS, it may have hung up on you because
of lack of activity on your part or because you exceeded your time
limit for the day. Try again.
The Modem Cannot Connect When Answering
•
Auto-answer may be disabled. Turn on auto-answer in your data-
comm program or send the command ATS0=1 to your modem
in terminal mode.
144
APPENDIX A: Troubleshooting
File Transfer Is Slower Than It Should Be
•
You may have an older UART. For best throughput, install a
16550AFN UART. See the “Quick Start” chapter for information on
how to identify your UART.
•
If you are running under Windows 3.1 and have a 16550AFN
UART, you must replace the Windows serial driver, COMM.DRV, to
take full advantage of the UART’s speed.
•
•
If you are using a slow transfer protocol, such as Xmodem or Ker-
mit, try Zmodem or Ymodem/G instead.
Is your line noisy? If there is static on your line, the modem has to
re-send many blocks of data to insure accuracy. You must have a
clean line for maximum speed.
•
•
Are you downloading a compressed file with MNP 5 hardware com-
pression enabled? Since hardware data compression cannot com-
press a file already compressed by an archiving program, the
transfer can be marginally slower with data compression enabled
than with it disabled.
Try entering the L8 (List Online Diagnostics) command in on-line
mode, making a screen print of the diagnostics listing, and
checking for parameters that may be unacceptable (number of re-
trains, round trip delay, etc.).
I Am Losing Data
•
If you are using data compression and a high speed serial port, set
the serial port baud rate to four times the data rate.
•
Your UART may not be reliable at serial port speeds over 9600 bps
or 19,200 bps. Turn off data compression, reset your serial port
speed to a lower rate, or replace your serial port with a faster one.
•
•
Make sure the flow control method you selected in software match-
es the method selected in the modem. If you have a Macintosh, you
may have the wrong cable for hardware flow control.
If you are running under Windows 3.1 and have a 16550AFN
UART, you may need to turn on the 16550’s data buffers and/or
replace the Windows serial driver, COMM.DRV.
145
SERIES II INTELLIGENT DATA/FAX MODEMS
•
Try entering the L8 (List Online Diagnostics) command in on-line
mode, making a screen print of the diagnostics listing, and
checking for parameters that may be unacceptable (number of re-
trains, round trip delay, etc.).
I Am Getting Garbage Characters on the Monitor
•
Your computer and the remote computer may be set to different
word lengths, stop bits, or parities. If you have connected at 8-N-1,
try changing to 7-E-1, or vice-versa, using your communications
software.
•
•
You may be experiencing line noise. Enable error correction, if it is
disabled, or hang up and call again; you may get a better connec-
tion.
At speeds above 2400 bps, the remote modem might not use the
same transmission or error correction standards as your modem.
Try connecting at a slower speed or disabling error correction.
(With no error correction, however, line noise can cause garbage
characters.)
•
Try entering the L8 (List Online Diagnostics) command in on-line
mode, making a screen print of the diagnostics listing, and
checking for parameters that may be unacceptable (number of re-
trains, round trip delay, etc.).
My Fax and Communications Software Won’t Run at the
Same Time
Communications devices can be accessed by only one application at a
time. Under DOS or Windows 3.1x, you can run either your fax software
or your datacomm software, but not both at the same time, unless you
have a special communications device management application. In
Windows 95, you can have data and fax communication applications
open at the same time, but they cannot use the same modem at the
same time.
146
APPENDIX A: Troubleshooting
A.2 Contacting Black Box
A.2.1 Recording Modem Information
Please fill in the following information on your Series II Modem on a
photocopy of this page. This will help tech support in answering your
questions.
Modem Model No.:
Modem Serial No.:
Modem Firmware Version:
COM Port #:
FAX Software Type and Version:
DataComm Software Type and Version:
The modem model and serial numbers are silkscreened on the bottom
of your modem. The software versions are printed on the diskette
labels. Type ATI1 to display the modem firmware version.
Please note the status of your modem before calling tech support. This
status can include LED indicators, screen messages, diagnostic test
results, problems with a specific application, etc. Use the space below
to note modem status:
147
SERIES II INTELLIGENT DATA/FAX MODEMS
A.2.2 Making the Call
If you determine that your Series II Modem is malfunctioning, do not
attempt to alter or repair the unit. It contains no user-serviceable parts.
Call Black Box Technical Support at 724-746-5500.
Before you do, make a record of the history of the problem. We will
be able to provide more efficient and accurate assistance if you have
a complete description, including:
•
•
•
•
•
the information requested in Section A.1.
the nature and duration of the problem.
when the problem occurs.
the devices/components involved in the problem.
any particular application that, when used, appears to create the
problem or make it worse.
•
the results of any testing you’ve already done.
A.3 Shipping and Packaging
If you need to transport or ship your Series II Modem:
•
•
Package it carefully. We recommend that you use the original
container.
If you are shipping the Modem for repair, make sure you include
the phone/line cords and power supply you’re using with it. If you
are returning the Modem, make sure you include everything you
received with it. Before you ship, contact Black Box to get a Return
Authorization (RA) number.
148
APPENDIX A: Troubleshooting
A.4 Upgrading the Series II Modem’s Firmware
The Series II Modem has a Flash PROM which contains firmware code
for the hardware and DSP code for the digital signal processor chips. At
various times, we may add enhancements and/or fixes to the firmware.
The flash technology used in the Series II Modem lets you load these
upgrades into the PROM or DSP chips through the modem's serial
port. If a Black Box Tech Support technician tells you that you need
to upgrade your firmware, do so, taking these steps:
1. Follow the technician’s instructions for downloading
FLASHPRO.ZIP and a new .HEX file from Black Box.
2. Unzip the FLASHPRO.ZIP file. Place this unzipped file and the
.HEX file in the same directory.
3. Run FlashPro by typing FLASHPRO, a space, -M and hitting
ENTER at the DOS prompt.
4. Highlight the "Configure" option in the MAIN MENU and hit
ENTER. Highlight "Active Port" and select the COM port to which
you have your modem attached. Highlight "Baud Rate" and select
the rate you want to program at. Hit ESC when finished.
5. Highlight the "Select File to Program" option in the MAIN MENU.
Highlight the .HEX file. Hit ESC when finished.
6. Highlight "Program Firmware" option in the MAIN MENU. When
you are prompted to confirm the file to program, press "Y".
7. If you need more assistance programming FLASHPRO, then
contact our tech support department again.
149
SERIES II INTELLIGENT DATA/FAX MODEMS
Appendix B - Dial Pulse and Tone-Dial Frequencies
Dial Pulses
B
Closed
Open
A
Digit 2
Digit 1
In the example above, the digit 2 is pulse dialed, followed by the digit 1.
Each pulse consists of an A mSec open and a B mSec closed, where A
will be either 60 or 67 mSec and B will be either 40 or 33 mSec, for a
total of 100 mSec per pulse, or a rate of 10 pulses per second. The
interdigital pause time is 800 mSec The pulse ratios are controlled
by the &P command.
Tone Dial Frequencies
Hz
Digits
697
1
4
7
2
5
8
3
6
9
A
B
C
770
852
941
Hz
*
0
#
D
1209
1336
1477
1633
150
APPENDIX C: Command Summary
Appendix C - Command Summary
Command Values
Description
AT
Attention Code that precedes most comd.
strings except A/, A: and Escape Codes.
RETURN
Pressing RETURN key executes most
commands.
$
In Dial Comd.
This symbol placed in dialing string enables
the modem to detect AT&T's "call card"
tones for accessing user's calling card to
originate an on-line connection.
A
Answer call, even if no ring present. Repeat
last command. (Do not precede this
command with AT. Do not hit RETURN to
execute.)
A:
Continuous redial of last number until
answered.
A/
Repeat previous command. (Do not
precede this command with AT.)
$An
n = 0 or 1
*$A0 discards data during auto-reliable time
period.
$A1 buffers data during auto-reliable time
period.
#An
n = 0 thru 3
*#A0 selects initial handshake at 33,600 to
31,200 to 28,800 to 24000 to 21,600 to
19,200 to 16,800 to 14,400 to 12,000 to 9600
to 4800 to 2400 to 1200 to 300 bps.
#A1 selects initial handshake at 33,600 bps
only.
#A2 selects initial handshake at 33,600 to
31,200 to 28,800 to 24000 to 21600 to
19,200 to 16,800 19,200 to 14,400 to 9600
to 4800 bps.
#A3 selects initial handshake at 2400 to
1200 to 300 bps.
* Factory Default Setting
151
SERIES II INTELLIGENT DATA/FAX MODEMS
Command Values
Description
&Bn
n = 0 or 1
*&B0 means normal transmit buffer size.
&B1 means reduced transmit buffer size.
&BSn
n = 0 or 1
&BS0 means maximum transmit block size
of 64 characters.
*&BS1 means maximum transmit block size
of 256 characters.
$BAn
&Cn
n = 0 or 1
n = 0,1,2,4
*$BA0 means speed conversion is on.
$BA1 means speed conversion is off.
&C0 forces Carrier Detect on.
*&C1 lets Carrier Detect act normally.
&C2 lets Carrier Detect drop S24 time on
disconnect.
&C4 resets modem when Carrier Detect
drops.
&CDn
Ds
n = 0 or 1
*&CD0 execute cleardown on disconnect.
&CD1 do not execute cleardown on
disconnect.
s = phone #
Dial a telephone number “s,” where s may
include up to 60 digits or T, P, R, comma
and ; characters.
* Factory Default Setting
Command Values
Description
DsNd
s = phone #
d = 0 thru 9
Store telephone number. To store, phone
number ”s“ is entered and followed by N
and then Directory Number “d.”
&Dn
n = 0 thru 3
&D0 DTR is ignored.
&D1 means modem returns to command
mode.
*&D2 lets modem react to DTR normally.
&D3 causes modem to reset to modem
default parameters.
152
APPENDIX C: Command Summary
%DFn
%DPn
n = 0 or 1
n = 0 or 1
*%DF0 Line Probe Data in Graph Format.
%DF1 Line Probe Data in Table Format.
*%DP0 do not read Line Probe
Information from DSP during handshaking.
%DP1 read Line Probe Information from
DSP during handshaking.
$Dn
En
n = 0 or 1
n = 0 or 1
*$D0 disables DTR Dialing.
$D1 enables DTR Dialing.
E0 means do not echo Command Mode
Character.
*E1 means do echo Command Mode
characters.
* Factory Default Setting
Command Values
Description
&En
n = 0 thru 15
&E0 means no error correction.
*&E1 means V.42 Auto-reliable Mode.
&E2 means V.42 Reliable Mode.
&E3 means no modem-initiated flow
control.
*&E4 means CTS modem-initiated flow
control.
&E5 means Xon/Xoff modem-initiated flow
control.
*&E6 means Xon/Xoff not passed through.
&E7 means Xon/Xoff passed through.
*&E8 means Enq/Ack pacing off.
&E9 means Enq/Ack pacing on.
*&E10 means Normal Mode flow control
off.
&E11 means Normal Mode flow control on.
&E12 means Pacing off.
*&E13 means Pacing on.
&E14 means data compression disabled.
*&E15 means data compression enabled.
153
SERIES II INTELLIGENT DATA/FAX MODEMS
$En
*$E0 disables error correction at 300 bps.
$E1 enables Autoreliable Mode at 300 bps.
$E2 enables Reliable Mode at 300 bps.
$EBn**
%En
n = 0 or 1
*$EB0 enables 10 bit mode.
$EB1 enables 11 bit mode.
n=0 thru 5
% E0 = Modem Won’t Escape.
*% E1 = +++ Method (default setting).
% E2 = Break Method.
% E3 = Either +++ or Break Method.
% E4 = No "OK" Response to +++
% E5 = "OK" Response to +++
* Factory Default Setting
** 336 Model (MD1641A) Only
Command Values
Description
#Fn
n = 0 thru 2
#F0 means no fallback when on-line.
#F1 means fallback from 33600 to 4800 bps
when on-line (increments of 2400 bps).
*#F2 means fallback to 4800 bps from 33.6K
bps/fall forward if line improves
(increments of 2400 bps).
&Fn
n = 0, 8 or 9
&F loads factory default values from ROM.
*&F8 reads factory default values and switch
settings when &F is issued.
&F9 reads parameters stored in non-volatile
memory when &F is issued.
$FCn**
$Fn
n = 0 or 1
n = 0 or 1
$FC0 means no transmit of 5 second
2100Hz signal.
*$FC1 transmits 5 second 2100Hz signal.
$F0 means do not fall back to normal
connect if CR received.
*$F1 means fall back to normal connect if
CR received.
154
APPENDIX C: Command Summary
&Gn
n = 0, 1 or 2
*&G0 turns off CCITT guard tones.
&G1 turns on CCITT 550 Hz guard tone.
&G2 turns on CCITT 1800 Hz guard tone.
Hn
n = 0 or 1
H0 means Hang Up (go on hook).
H1 means Go Off Hook.
$Hn
n = 1 thru 3
$H1 brings up Help Screen #1.
$H2 brings up Help Screen #2.
$H3 brings up Help Screen #3.
In
n = 0,1or 2
Read Only
I0 requests modem ID #.
I1 requests firmware revision #.
I2 for MTS internal use.
I9
Command enables display of Windows 95
Autodetect characteristics
* Factory Default Setting
** 336+ Model (MD1640A) Only
Command Values
Description
L
Lists all stored telephone numbers in
memory.
L5
L6
L7
L8
L9
L10
L5 lists all current operating parameters.
L6 lists all current S-Register values.
L7 lists additional parameters.
L8 lists On-Line Diagnostics.
L9 Displays Signal Strength Information.
L10 Displays Signal to Noise Ratio
Information.
L11
L11 Displays Noise Information.
155
SERIES II INTELLIGENT DATA/FAX MODEMS
#Ln
n = 0 thru 3
*#L0 means modems negotiate V.42 Mode.
#L1 means MNP on and LAP-M off.
#L2 means LAP-M on and MNP off.
#L3 means no detection phase but go
directly to LAP-M.
* Factory Default Setting
Command Values
Description
Mn
n = 0 thru 3
M0 means Monitor speaker always Off.
*M1 means Monitor speaker On until
carrier detected
M2 means Monitor speaker always On.
M3 Monitor speaker on during dialing/off
during handshaking.
$MBn
n = speed
$MB300 selects 300 bps on-line.
$MB1200 selects 1200 bps on-line.
$MB2400 selects 2400 bps on-line.
$MB4800 selects 4800 bps on-line.
$MB9600 selects 9600 bps on-line.
$MB14400 selects 14400 bps on-line
$MB19200 selects 19200 bps on-line
$MB28800 selects 28800 bps on-line
*$MB33600 selects 33600 bps on-line
&Mn
Nd
n = 0 or 1
*&M0 selects Async when on-line.
&M1 selects Sync when on-line.
d = 0 thru 9
d = 0 thru 9
Dial stored telephone number “d” (Do not
include the letter D in this command.)
NdNe
Number Linking. If first number dialed
(“d”)
e = any other
number 0
thru 9
is busy, another stored number (“e”) may
be automatically dialed.
O
Exit Command Mode and go into On-Line
Mode.
156
APPENDIX C: Command Summary
P
In Dial Comd.
n = 0 or 1
*Modem will pulse-dial numbers following
the P.
&Pn
#Pn
*&P0 means 60-40 pulse ratio.
&P1 means 67-33 pulse ratio.
n = 0, 1, or 2
*#P0 selects no parity.
#P1 selects odd parity.
#P2 selects even parity.
* Factory Default Setting
Command Values
Description
Qn
n = 0, 1 or 2
*Q0 means Result Codes sent.
Q1 means Result Codes will be suppressed
(quiet).
Q2 means Dumb Answer Mode.
&Qn
Rn
n = 0 or 1
n = 0 or 1
*&Q0 selects Series II command set.
&Q1 selects AT command set.
*R0 means modem will not reverse modes.
(In Dial Comd.) R1 means modem will reverse modes.
&Rn
n = 0, 1 or 2
&R0 lets Clear to Send act normally.
*&R1 forces Clear to Send on.
&R2 drops for 1 second on disconnect.
&RP
$Rn
Command Initiates a Retrain that makes
the processor read Line Probe Information
(valid only in V.34 mode).
n = 0 or 1
n = 0 or 1
*$R0 means disconnect after 12 retransmits.
$R1 means do not disconnect after 12
retransmits.
&RFn
&RF0 selects CTS follows RTS.
*&RF1 selects CTS to act independently
* Factory Default Setting
157
SERIES II INTELLIGENT DATA/FAX MODEMS
Command Values
Description
Sr=n
r = 0-11, 13,
15-19, 24-26,
Sets value of Register “r” to value of “n”,
where “n” is entered in Decimal format.
29, 30, 32, 34...
Sr?
r = 0-11, 13,
15-19, 24-26,
30, 32 or 34...
Reads value of Register “r” and displays
value in 3-digit Decimal format.
$SBn
n = speed
$SB300 selects 300 bps at serial port.
$SB1200 selects 1200 bps at serial port.
$SB2400 selects 2400 bps at serial port.
$SB4800 selects 4800 bps at serial port.
$SB9600 selects 9600 bps at serial port.
$SB19200 selects 19,200 bps at serial port.
$SB38400 selects 38,400 bps at serial port.
$SB57600 selects 57600 bps at serial port.
*$SB115200 selects 115200 bps at serial
port.
&SFn
&Sn
n = 0 or 1
*&SF0 selects DSR follows CD.
&SF1 selects DSR independent.
n = 0, 1 or 2
&S0 forces Data Set Ready On.
*&S1 lets Data Set Ready act normally.
&S2 Data Set Ready drop is regulated by
S24 on disconnect.
$SPn
n = 0 or 1
*$SP0 disables UUCP Spoofing
$SP1 enables UUCP Spoofing
* Factory Default Setting
158
APPENDIX C: Command Summary
Command Values
Description
T
In Dial Comd.
Modem will tone-dial numbers following
the T.
&Tn
n = 4 or 5
&T4 means Enable Response to Request for
Remote Digital Loopback.
*&T5 means Disable Response to Request
for Remote Digital Loopback.
#Tn
Un
n = 0 or 1
#T0 turns off Trellis Coded Modulation
*#T1 turns on Trellis Coded Modulation
n = 0, 1, 2, or 3
U0 places modem in Analog Loop
Originate Mode.
U1 places modem in Analog Loop Answer
Mode.
U2 places modem in Remote Digital
Loopback test mode.
U3 places modem in Local Digital
Loopback test mode.
$VDn
Vn
n= 0 or 1
n = 0 or 1
*$VD0 disables Voice/Data Dialing
$VD1 enables Voice/Data Dialing
V0 means Result Codes sent as digits (terse
response).
*V1 means Result Codes sent as words
(verbose response).
#Vn**
n = 0 or 1
#V0 enables V.32terbo handshaking process
#V1 disables V.32terbo handshaking process
W
In Dial Comd.
n = 0 or 1
Wait for new dial-tone.
&Wn
&W0 causes modem to store its current
parameters in non-volatile RAM, and
modem will load these for future sessions
instead of reading factory ROM defaults,
unless &F command used.
*&W1 causes modem to not store
parameters.
* Factory Default Setting
** 336 Model (MD1641A) Only
159
SERIES II INTELLIGENT DATA/FAX MODEMS
Command Values
Description
Xn
n = 0,1,2,3 or 4
*X0 selects Basic Result Codes (w/o
CONNECT 1200, CONNECT 2400).
X1 selects Extended Result Codes
(w/CONNECT 1200, CONNECT 2400).
X2 selects Standard AT Command set
with NO DIAL TONE.
X3 selects Standard AT Command set
with BUSY.
X4 selects Standard AT Command set
with NO DIAL TONE and BUSY.
&Xn
#Xn
Yn
n = 0, 1, or 2
n = 0 or 1
*&X0 has sync clock controlled by DIP
switch.
&X1 forces external sync clocking.
&X2 forces slave sync clocking.
*#X0 selects single XOFF character sent
until XON level returns.
#X1 selects multiple XOFF characters
after buffer level is full.
n = 0 or 1
*Y0 disables sending or responding to
(In Dial Command) long space “break”.
Y1 enables sending or responding to long
space “breaks”.
Z
All configuration parameters are reset to
default values.
,
In Dial Command Causes pause during dialing.
;
In Dial Command Causes return to Command Mode after
dialing.
!
In Dial Command Causes modem to flash On-Hook.
@
In Dial Command Causes modem to wait for ringback, then
5 seconds of silence before processing
next part of command.
* Factory Default Setting
160
APPENDIX C: Command Summary
Command
Values Description
+++AT<CR>
In-band Escape Sequence. Places modem in
Command Mode while still remaining On-
Line. Enter +++ followed by the letters A
and T, up to ten command characters, and
a RETURN.
BREAK AT<CR>
Out-of-band Escape Sequence. Places
modem in Command mode while still
remaining On- Line. Enter a BREAK signal,
followed by the letters A and T, up to sixty
command characters, and hit RETURN.
Callback Security/Remote Configuration Command Summary
Command
#DBn
Description
#DB0 disables Callback Security and answering Yes
to the prompt turns off Callback Security and
erases stored phone numbers and passwords.
Answering No to the prompt aborts the command.
#DB1 activates remote and local password security.
#DB2 activates remote password security.
#CBNyyxxxxxx
Callback password with xxxxxx being callback
password and yy being the memory location.
Callback password xxxxxx must start with a non-
numeric character and upper/lower case sensitive.
Callback password xxxxxx must be a minimum of
6 and maximum of 10 characters. yy memory
locations are from 0 to 29. Must specify P (pulse)
or T (tone) dialing in string.
+ - Dxxxxxx???Nxx
Callback Phone Numbers xxxxxx with the +
preceding the phone number indicating the
callback modem phone number for the
corresponding password at the same memory
161
SERIES II INTELLIGENT DATA/FAX MODEMS
location. The (-) preceding the phone number
enables direct entry when the caller uses the
correct password without the callback modem
having to return the call. The ??? entry at the end
of the phone number represents an extension
added to the main phone number. The Nxx is the
memory location of the callback phone number
and password.
#Pn
Parity of the prompt messages sent by the callback
modem.
#P0 is no parity
#P1 is odd parity
#P2 is even parity
Command
#RCBNxx
Description
Erases the callback password stored at memory
location xx. Memory locations are 0 to 29.
#RDNxx
Erases the callback phone number stored at
memory location xx. Memory locations are 0 to 29.
Password Command Summary
Command
Description
#Ixxxxxxxxxx
Login Password is any keyboard characters (x)
(upper/lower case sensitive), minimum 6 and
maximum 10 characters. The default Login
Password is #IBLACK BOX.
#Syyyyyyyyyy
Setup Password is any keyboard characters (y)
(upper/lower case sensitive), minimum 6 and
maximum 10 characters. The default Setup
Password is #SMODEMSETUP.
162
APPENDIX C: Command Summary
V.25bis Commands
Command
Description
$Vn
$V0 returns modem to AT command mode when
in V.25bis mode.
$V1 enables V.25bis mode of operation.
$V2 allows modem to receive one V.25bis
command while in AT command mode without
leaving AT command mode.
$V5 DSR follows DTR in V.25bis mode.
$V6 DSR does not follow DTR in V.25bis mode.
CSPs
Changes the serial bps rate.
CSP0300 - 300 bps
CSP1200 - 1200 bps
CSP2400 - 2400 bps
CSP4800 - 4800 bps
CSP9600 - 9600 bps
CSP19200 - 19200 bps
CSP38400 - 38400 bps
CSP57600 - 57600 bps
CSP115200 - 115200 bps
CRNdd
Dials phone number dd where dd can be up to
20 characters (0 through 9, *, #, P, T and :). Phone
number is checked against the Delayed and
Forbidden Number lists before dialed.
CRIdd;nn
DIC or CIC
Dials dd same as CRN Command and ignores nn
identification string. The disregard or connect to
incoming calls commands are used for auto-
answer operations.
DIC stops the modem from answering incoming
calls.
CIC causes the modem to answer incoming calls.
163
SERIES II INTELLIGENT DATA/FAX MODEMS
Appendix D - DIP-Switch Summary
Asynchronous Mode
DIP-Switch Condition
Effect
#1
UP*
Down
DTR dependent on interface
DTR forced On at all times
#2
UP*
Down
Hardware Flow Control
Xon/Xoff Flow Control
#3
UP
Down*
-15 dB Transmission (leased line)
-9 dB Transmission (leased line)
#4
UP*
Down
UUCP Spoofing Off
UUCP Spoofing On
#5
UP*
Down
Automatic Answer On
Automatic Answer Off
#6
UP*
Down
Max throughput On
Max throughput Off
#7
UP
Down*
RTS dependent on Interface
RTS forced On at all times
#8
UP
Down*
Disable Command Mode
Enable Command Mode
#9
UP
Down*
Local Digital Loopback On
Remote Digital Loopback On
#10
#11
#12
UP*
Down
Dial-Up Operation
Leased Line Operation
UP
Down*
"AT" Responses
Series II Responses
UP
Down*
Synchronous Mode On
Asynchronous Mode On
*Factory Default Setting
164
APPENDIX D: DIP-Switch Summary
Synchronous Mode
DIP-Switch Condition
Effect
#1
#2
#3
#4
#5
#6
#7
#8
#9
#10
UP*
Down
DTR Dependent On interface
DTR forced On at all times
UP*
Down
SDLC Mode On
BSC Mode On
UP
Down*
Command Mode Response Off
Command Mode Response On
UP*
Down
AS/400 Mode Off
AS/400 Mode On
UP*
Down
Answer Mode On
Originate Mode On
UP*
Down
Slave Clocking Off
Slave Clocking On
UP
Down*
RTS Dependent on interface
RTS forced on at all times
UP
Down*
Command Mode Off
Command Mode On
UP
Down*
Local Digital Loopback On
Remote Digital Loopback On
UP*
Dial-Up Operation
165
SERIES II INTELLIGENT DATA/FAX MODEMS
Down
Leased Line Operation
#11
#12
UP
Down*
External Clock selected
Internal Clock selected
UP
Down*
Synchronous Mode On
Asynchronous Mode On
*Factory Default Setting
DIP Switches #13-16
DIP-Switch Condition
Effect
#13/#14
#13/#14
#13/#14
#13/#14
UP/UP*
28.8 K bps Operation
19.2 K bps Operation
14.4K bps Operation
9600 bps Operation
Down/UP
UP/Down
Down/Down
Note: The modem baud rate command (e.g.,$MB33600) overrides the
setting of these speed selection switches (DIP switches #13 and #14).
#15
UP*
Down
CD/DSR from Interface (Sync & Async)
CD/DSR Forced On
#16
UP
Down*
2-Wire Leased Line (Sync & Async)
4-Wire Leased Line
* Factory Default Setting
166
APPENDIX E: S-Register Summary
Appendix E - S-Register Summary
S-REG. UNIT
RANGE DEFAULT DESCRIPTION
S0
S1
S2
Rings
Rings
ASCII
0-255
0-255
0-127
1
Sets number of rings
before modem answers.
0
Counts rings which have
occurred.
43
Sets Escape Code
character (default is
plus “+” sign).
S3
S4
ASCII
ASCII
0-127
0-127
13
10
Sets character recog-
nized as RETURN
(default is CTRL-M).
Sets character
recognized as LINE
FEED (default is CTRL-
J).
S5
ASCII
0-32,127
8
Sets character recog-
nized as BACKSPACE
(default is CTRL-H).
S6
S7
Seconds 2-255
Seconds 1-255
2
Determines wait-time
for dial tone.
45
Determines how long
modem waits for carrier
before aborting call.
S8
S9
Seconds 0-255
100 mSec 1-255
2
6
Sets pause time caused
by a comma character in
a dial command.
Sets carrier detect
response time.
167
SERIES II INTELLIGENT DATA/FAX MODEMS
S-REG. UNIT
RANGE DEFAULT DESCRIPTION
S10
100 mSec 1-255
7
Sets delay time between
when carrier is lost and
when modem
disconnects.
S11
S13
S15
1 mSec
ASCII
1-255
0-127
70
37
20
Sets time duration of
and spacing between
tones in tone-dialing.
Defines Remote
Configuration Escape
Character
Seconds 10-255
Attempts 1-255
Defines time delay for
Callback attempts after
initial passwords have
exchanged.
S16
4
Defines the number of
Callback attempts after
initial passwords have
exchanged between
modems.
S17
S18
10 mSec 0-2.5
250 mSec Defines length of break
time (space) to PC.
30 min
10-255
30
Defines how often
leased-line is checked
and restoral attempted.
S19
Minutes 0-255
1
Timer used in dial
backup mode. Specifies
time duration modem
attempts to restore
leased line connection.
168
APPENDIX E: S-Register Summary
S-REG. UNIT
RANGE DEFAULT DESCRIPTION
S24
S25
S26
S29
50 mSec 0-255
20
Sets DSR/CTS/CD
dropout time. Default
(20) equals one second.
100 mSec 0-255
0
Sets DTR dropout time.
0 default equals
50 mSec.
Failed
Attempts
0-255
1-255
0
Specifies number
of failed password
attempts allowed.
1
20
Specifies the amount of
idle time can elapse
between AT commands
after the SETUP
password has been
entered
S30
S32
Minutes 0-255
100mSec 0-255
0
Inactivity timer used to
disconnect modem.
20
Sets time that modem
waits for a <RETURN> to
be entered during
escape sequence
execution.
S34
Chars.
0-60
10
Buffer size for number
of characters in AT
command string after
on-line escape sequence,
before buffer is cleared
and escape sequence
aborted.
169
SERIES II INTELLIGENT DATA/FAX MODEMS
S-REG. UNIT
RANGE
DEFLT. DESCRIPTION
S36
S37
S48
Seconds 0-255
0
5
0
S36 sets the time
between DTR inactive
and the modem going
off-hook (busy-out).
Seconds 0-255
S37 sets the time allowed
DTR active and the
modem responding on-
hook (not busy).
N/A
33, 31,
S48 sets speed modem
connects within scope
of Enhanced V34 mode
(e.g., S48 = 21 means
maximum connect
speed is 21.6K). This
register is useful when
line conditions will not
support higher V34
speeds. The default
value is 0, which
28, 26, 24,
21, 19, 16,
14, 12, 96
and 48
indicates a connection
attempt of 28.8K.
170
APPENDIX F: Result Code Summary
Appendix F - Result Code Summary
TERSE
(Digit)
VERBOSE
(Words)
Effect
0
1
2
3
4
5
OK
Command was executed without
error; ready for next command.
CONNECT
RING
Modem has detected carrier and
gone on-line.
Modem has detected ring caused
by incoming call.
NO CARRIER
ERROR
No carrier signal has been detected
within allowed time.
Error in Command line (too many,
or invalid, characters).
CONNECT 1200
Modem has detected carrier at
1200 bps and gone on-line.
6
7
8
9
NO DIAL TONE
BUSY
No dial tone has been detected.
A busy signal has been detected.
Remote system did not answer.
NO ANSWER
CONNECT 2400
Modem has detected carrier at
2400 bps and gone on-line.
11
12
13
CONNECT 4800
CONNECT 9600
Modem has detected carrier at
4800 bps and gone on-line.
Modem has detected carrier at
9600 bps and gone on-line.
CONNECT 14400 Modem has detected carrier at
14400 bps and gone on-line.
171
SERIES II INTELLIGENT DATA/FAX MODEMS
TERSE
(Digit)
VERBOSE
(Words)
Effect
19
21
24
26
28
31
33
CONNECT 19200 Modem has detected carrier at
19200 bps and gone on-line.
CONNECT 21600 Modem has detected carrier at
21600 bps and gone on-line.
CONNECT 24000 Modem has detected carrier at
24000 bps and gone on-line.
CONNECT 26400 Modem has detected carrier at
26400 bps and gone on-line.
CONNECT 28800 Modem has detected carrier at
28800 bps and gone on-line.
CONNECT 31200 Modem has detected carrier at
31200 bps and gone on-line.
CONNECT 33600 Modem has detected carrier at
33600 bps and gone on-line.
Note: If Series II Modem is used in MNP Reliable mode, the following
responses change:
1R
CONNECT RELIABLE
5R
9R
CONNECT 1200 RELIABLE
CONNECT 2400 RELIABLE
CONNECT 4800 RELIABLE
CONNECT 9600 RELIABLE
CONNECT 14400 RELIABLE
CONNECT 19200 RELIABLE
CONNECT 21600 RELIABLE
CONNECT 24000 RELIABLE
CONNECT 26400 RELIABLE
CONNECT 28800 RELIABLE
CONNECT 31200 RELIABLE
CONNECT 33600 RELIABLE
11R
12R
13R
19R
21R
24R
26R
28R
31R
33R
172
APPENDIX F: Result Code Summary
Note: If Series II Modem is used in LAP-M reliable mode, the following
responses change:
1L
CONNECT LAPM
5L
9L
CONNECT 1200 LAPM
CONNECT 2400 LAPM
CONNECT 4800 LAPM
CONNECT 9600 LAPM
CONNECT 14400 LAPM
CONNECT 19200 LAPM
CONNECT 21600 LAPM
CONNECT 24000 LAPM
CONNECT 26400 LAPM
CONNECT 28800 LAPM
CONNECT 31200 LAPM
CONNECT 33600 LAPM
10L
12L
13L
19L
21L
24L
26L
28L
31L
33L
Note 1: If the Series II Modem is used with data compression, the word
COMPRESSED or the letter C is added to result codes.
Note 2: If the Standard AT Command Set 2400 responses are selected
with the &Q command, the following responses change:
9
(not used)
10
CONNECT 2400
Modem has detected carrier at
2400 bps and
gone on-line.
173
SERIES II INTELLIGENT DATA/FAX MODEMS
Appendix G - V.25bis Operation
Chapter 5 described a set of commands which let the Series II Modem
dial, hang-up, and be configured for various applications. However,
these commands, the AT command set, are only functional when the
DTE transmits data asynchronously. That is, they cannot be used with
synchronous equipment such as that found in IBM's Binary Synchro-
nous Communications (BSC) and Synchronous Data Link Control
(SDLC)* environments.
The ITU V.25bis commands provide you with an alternate set of com-
mands and responses to those described in Chapter 5 for applications
in which the DTE is synchronous. V.25bis commands support dialing
functions in asynchronous or synchronous mode according to the rec-
ommendations of the ITU; however, the AT commands are understood
to reign in the asynchronous world, while the V.25bis commands are
relegated to the synchronous world of datacomm. If you need to
establish a datacomm link over Public Switched Telephone Network
(PSTN) dial-up services, and your equipment outputs a synchronous
data stream, V.25bis commands are essential. V.25bis mode AT
commands do not include any modem configuration commands. You
can execute normal AT commands in V.25bis mode for modem
configuration.
Delayed and Forbidden Numbers
V.25bis provides the facility to delay failed call retry attempts by putting
numbers that failed to connect on a special Delayed Number list. Subse-
quent dialing of these numbers will be delayed (time specified by a
country regulation) and an appropriate message displayed. If the
number is retried more than the maximum allowed number of times
(number is also specified by country regulation), it is placed on the
Forbidden Numbers list, and no further retries will be allowed. When
the Forbidden Numbers list is full, no dialing is allowed and a CFIFF
indication is given. The modem in AT command mode will respond
with NO CARRIER. If country regulations require that the Forbidden
Numbers list be checked in AT mode, then NO CARRIER will be the
response to a dial attempt in AT mode. Numbers will also be put on the
Forbidden Numbers list if the Delayed Numbers list is full and a new
number fails for the first time. In that case, the new number will be
174
APPENDIX G: V.25bis Operation
added to the Delayed Number list and the oldest existing number
added to the Forbidden Numbers list. Numbers are removed from the
Forbidden Numbers list by after a certain time has past (also by country
regulation).
Some country regulations have numbers remain on the Forbidden
Numbers list permanently. The Delayed Number and Forbidden
Numbers lists are eight numbers long (20 characters each).
V.25bis Operation
Operation in V.25bis mode is similar to AT command mode in that
certain DIP-Switch functions are important to its operation. V.25bis does
not include any speed detection for asynchronous mode, so when you
are giving commands, you must stay in your initial speed (i.e., if you
change your terminal speed while entering an AT command, you will
get no responses). In synchronous mode, the modem supplies the
clock, so the synchronous terminal “knows” the speed.
You must be in V.25bis mode for the commands described here to
function. Most AT commands will also function, except those associated
with dialing such as ATD, ATN, ATO, and ATU. To get into V.25bis mode,
you type AT$V1. At this point your modem does no more speed or
parity detection (things associated with asynchronous operation). To
get out of V.25bis mode and back into AT command mode, enter
AT$VO. The AT$V2 command allows you to run one V.25bis command
from AT command mode without leaving AT command mode.
There is no command to select between asynchronous and synchronous
V.25bis operation. The position of DIP-Switch #12 selects between
modes. For synchronous mode, DIP-Switch #12 must be UP, and the AT
command mode enabled.
Another asynchronous mode concern is the problem of connecting at a
different speed than the speed at which the serial port is set. If your
modem port speed is different from the serial port speed, you must
either:
1) Enable speed conversion and have flow control on, or
2) Enable connect responses (with the ATX1 command) and change
the serial baud rate after receiving a connect message.
175
SERIES II INTELLIGENT DATA/FAX MODEMS
If the $VD1 command is entered when in Auto-Answer mode, the
modem answers immediately upon receiving the first ring.
There is no disconnect message (NO CARRIER) if a normal connection
is made.
V.25bis Set-Up and Initialization
Before you operate your modem in the V.25bis mode, you need to make
sure it is set up properly (various RS-232 lines such as DSR and CTS act
as specified in the V.25bis standard). Setup involves proper DIP-Switch
settings and soft-switches (software controlled conditions).
V.25bis DIP-Switches
#1 Unforced DTR
#2 NA
#3 NA
#4 NA
#5 Auto-Answer enabled
#6 Async - Max throughput set
Sync - Slave Clocking unforced
#8 - Command Mode forced
#9 - Digital Loopback Off
#10 - Dial-Up
#11 - Async - AT/Series II Resp.
#12 - Async/Sync mode set per requirements
176
APPENDIX G: V.25bis Operation
V.25bis Mode AT Commands
The following commands will either alter standard V.25bis behavior (so
you must be careful in their use) or they are not allowed, as indicated.
All other commands can be used in V.25bis operation.
A
Not Allowed
A/
A:
Not Allowed
Not Allowed
D
Not Allowed
D...N
$D
E
Not Allowed
Alters Operation ($D1 in V25bis is direct call mode)
Alters Operation
&F
Alters Operation (removes modem from asynchronous
V.42bis mode)
N
Not Allowed
Not Allowed
Not Allowed
Not Allowed
Not Allowed
Not Allowed
Not Allowed
N...N
O
P
T
U
W
X
Alters Operation (X0 no connect message, X1 connect
message)
,
Not Allowed
Not Allowed
Not Allowed
Not Allowed
;
!
@
+++AT<CR> Not Allowed
177
SERIES II INTELLIGENT DATA/FAX MODEMS
V.25bis Responses (Result Codes)
When in V.25bis mode (the AT$V1 command executed), your modem
provides you with several responses which can help you follow the
progress of V.25bis operations. These are similar to the Result Codes
associated with AT Command mode operation. The V.25bis responses
are in the form of three-character mnemonics as listed below:
INC
Incoming Call (same as RING indicator)
A valid V.25bis command has been attempted
Call delayed for t minutes (number on Delayed list)
Call failure indicator where rr equals:
VAL
DLCt
CFlrr
et - Engaged tone (same as BUSY)
nt - Call Answered but No Answer Tone
ab - Call Not Answered
fc - Number on Forbidden List
ns - Number not stored in memory
ua - User Abort
nd - No Dialtone
ff - Forbidden List full
LSNmm;dd...dd
LSDmm;dd...dd
LSFmm;dd...dd
CON ssss
Phone number in V.25bis memory
Phone number on the Delay list
Phone number on the forbidden list
Connection at ssss speed (if X1 in effect)
V.25bis AT Commands
The AT commands associated with V.25bis mode are described as
follows. Note that one command enables and disables V.25bis mode and
the rest are only operable in the V.25bis mode.
178
APPENDIX G: V.25bis Operation
Enable/Disable V.25bis Mode ($V) Command
The function of the $V command is to select the V.25bis mode in
asynchronous mode. (Synchronous mode is set up with switches. For
example, the modem could be in AT command mode, (AT$V1), and if
synchronous mode is enabled with AT Command mode enabled, then
V.25bis mode is selected). Prior to executing this command, make sure
that your modem is properly set up to perform the type of operation
you will be performing. Refer to the initialization section of this
appendix for information about modem set-up. When in V.25bis mode,
most normal AT commands will also function (except D,N,O and U).
V.25bis operates in asynchronous or synchronous modes (depending on
the position of DIP-Switch #12), and does not check for terminal speed
(so do not change speeds while in this mode) or parity. In synchronous
mode, speed is not important since the internal clocks provide synchro-
nization.
To place your modem in V.25bis mode from asynchronous mode, enter
the AT$V1 command. To return to AT command mode, enter the
AT$V0 command. AT$V2 allows you to run one V.25bis command from
AT command mode without leaving AT command mode (the V.25bis
command follows $V2 on the command line).
Change Serial Baud Rate (CSP) Command
The CSP command will change the serial baud rate of your modem by
entering CSPsssss where sssss can equal:
0300
1200
2400
4800
=
=
=
=
=
=
=
=
=
300 bps
1200 bps
2400 bps
4800 bps
9600 bps
19200 bps
38400 bps
57600 bps
115200 bps
9600
19200
38400
57600
115200
179
SERIES II INTELLIGENT DATA/FAX MODEMS
Dial Phone Number Provided (CRN) Command
The CRN command permits the dialing of the phone number immedi-
ately following it (from the command line). It is similar to the D com-
mand of the AT command set, except that the number is first checked
against the Delayed Number and Forbidden Number list. If permitted,
depending on the country regulations in effect, the number will then
be dialed. For example, if you enter CRN7859875 and hit RETURN,
your modem will check the two lists. If the number is on the Delayed
Numbers list, you can dial that number again after t minutes have
passed. If the number is on the Forbidden list, a CFIFC message will be
displayed.
You can use various commands from the AT command set within the
CRN command line to facilitate the dialing process, such as P, T, or :
for pulse dialing, tone dialing and wait for dial tone. V.25bis supports
“smart” dialing.
To dial a phone number, enter CRNdd...dd where dd...dd is the phone
number, which can be up to 20 characters long using any character on
the telephone pad (0 through 9, *, #, P, T, and :).
Some additional dialing characters may be available, based on country
regulations.
180
APPENDIX G: V.25bis Operation
Listing Delayed Phone Numbers (RLD) Command
When a phone number is dialed by a CRN command and a connection
is not made, the number is entered in the modem's V.25bis Delayed
Number list along with the number of retry attempts. Any further
dialing attempts will be delayed some amount of time (determined by
the regulations of each country). While the delay is in progress, the
modem will give a DLC indication. The list contains eight numbers.
When filled, the next number failing “bumps” off the oldest number on
the list onto the Forbidden Number list. Numbers on the Delayed
Number list that succeed in a connect attempt are removed. If a certain
number of failed attempts occur (the number of failed attempts is
specified by each country), the number is entered into the V.25bis
Forbidden Phone Number List. Forbidden phone numbers cannot be
dialed at all. To list the phone numbers on the V.25bis Delayed Phone
Number List, enter RLD and hit RETURN.
Listing Forbidden Phone Number (RLF) Command
Those phone numbers that have failed to connect the required number
of times as specified by country regulations are removed from the
Delayed Number list and entered onto the V.25bis Forbidden Number
list. Numbers on the Forbidden Number list cannot be dialed at all for
some maximum amount of time, which is also specified by country reg-
ulations. In some countries, the time might be one hour, and in others
the number may never be dialed again. The forbidden list is eight num-
bers long, with the newest number replacing the oldest if the memory is
full. To list the numbers in the Forbidden list enter RLF and hit
RETURN.
Disregard or Connect to Incoming Calls (DIC or CIC)
Command
The Disregard or Connect to Incoming Calls commands are used for
Auto-Answer operations. Depending on the country regulations, your
modem will wait some amount of time or number of rings before an-
swering the call. During that time, you can stop the modem from
answering the call by entering the DIC (Disregard Incoming Calls)
command. The CIC (Connect to Incoming Calls) command will cause
your modem to answer the call (either reversing the effect of a DIC
181
SERIES II INTELLIGENT DATA/FAX MODEMS
command or simply have your modem answer the call immediately
without waiting the regulation time before answering).
DTR Dialing ($D) Command
DTR Dialing is an alternate method of causing the Series II Modem to
automatically dial a number. Data Terminal Ready (DTR) is a signal
that comes into the modem from the terminal or computer to which it
is connected via pin 20 of the RS232 interface. In DTR Dialing, the
modem will automatically dial a stored number as soon as it receives a
high DTR signal. The DTR Dialing method is popular when using the
Modem in synchronous applications.
To enable DTR Dialing, enter the command AT$D1 and hit Return. The
modem will now dial the phone number you have stored as N0 when it
receives a high DTR signal (see the D...N command in Chapter 5).
DTR must remain high for the duration of the call, until disconnect.
To disable DTR Dialing, enter the command AT$D0 (or AT$D) and hit
RETURN.
When you use DTR Dialing, be sure that DIP-Switch #1 is in the UP
position, so that DTR is not forced on.
In addition, when using DTR Dialing in a synchronous application,
be sure that DIP-Switch #8 is in the UP position to disable V.25bis
Command mode.
182
APPENDIX G: V.25bis Operation
ITU V.25bis Country Specific Information
Due to the flexibility of the V.25bis standard, each country may establish
specific regulations governing the way operations are handled. Here
are details about how each country's specific regulations can affect the
operation of V.25bis in modems that the Series II Modem might
communicate with. (This information is provided for your reference
only; the Series II Modems are not approved for operation outside the
U.S. and Canada.)
1. Italy
a) Command/Indication modifications
1. Phone number indications include status ;ZPSTTT
a)Z - U, D, or F, for Unrestricted, Delayed or Forbidden
b)P - Delay time if delayed
c)S - Number of retries so far
d)
TTT - Interdiction time to further attempts
b)Delayed and Forbidden list behavior
1. 5 retries without delay
2. 2 minute delay between next 4 retries
3. After 9 retries the number is put on the forbidden list
4. 120 minute timer is started on entry to delay list
5. When it runs out, the number is removed from which ever list
it is on
c)Auto-Answer mode behavior
1. Auto-Answer in 5 seconds if no DIC
2. Get 10 seconds after DIC to enter CIC
3. If 10 seconds times out then no connection is possible
183
SERIES II INTELLIGENT DATA/FAX MODEMS
2. Switzerland
a)Command/Indication modification
1. Modem must remain on-hook for 5 seconds after disconnect
2. Modem must remain on-hook for 5 minutes after 4
consecutive failed calls
3. If modem must remain on-hook, then it is “paused”
4. If the modem is paused and a call is attempted a PAU
indication is given.
a)PAUt Modem is paused for t minutes
b)Delayed and Forbidden list behavior
1. 2 minute delay between 4 retries
2. After 4 retries the number is put on the forbidden list
3. The number remains on the forbidden list forever
c)Auto-Answer behavior
1. Auto-Answer mode after 2 rings if no DIC
3. Austria
a)Command/Indication modification (none)
b)Delayed and Forbidden list behavior
1. No delay between retries
2. After 2 retries to numbers that answer, but give no answer
tone (CFINT), the number is put on the forbidden list
3. After 10 retries with busy or no dialtone, the number is put on
the forbidden list
4. The number remains on the forbidden list forever
5. Delayed and Forbidden Numbers lists are checked when
184
APPENDIX G: V.25bis Operation
dialing in AT mode. If dialing is not possible then NO
CARRIER is the response.
c)Auto-Answer behavior
1. Auto-Answer in 5 seconds if no DIC
4. France
a)Command/Indication modification (none)
b)Delay and Forbidden list behavior
1. 2 min. delay after 1st call, 4 after 2nd, 6 after 3rd, etc.
2. After 5 retries, the number is put on the forbidden list
3. The number remains on the forbidden list forever
4. Delayed and Forbidden Numbers lists are checked when
dialing in AT command mode. If dialing is not possible then
No Carrier is the response.
c) Auto-Answer mode behavior
1. Auto-Answer in 5 seconds if no DIC
5. Belgium
a)Command/Indication modification (none)
b)Delay and Forbidden list behavior
1. 1 min. delay between calls
2. After 4 retries, the number is put on the forbidden list
3. The number remains on the forbidden list for 1 hour after
entry to forbidden list
4. Delayed and Forbidden Numbers lists are checked when
dialing in AT command mode. If dialing is not possible then
No Carrier is the response.
c)Auto-Answer behavior
1. Auto-Answer in 5 seconds if no DIC.
185
SERIES II INTELLIGENT DATA/FAX MODEMS
6. Singapore
a)Command/indication modifications
1. Dialing digit ‘=’ means wait for dialtone (acts the same as ‘:’ in
dialing string)
b)Delay and Forbidden list behavior
1. 5 retries without delay
2. 2 minute delay between next 4 retries
3. After 9 retries the number is put on the forbidden list
4. 120 minute timer is started on entry to delay list
5. When it runs out, the number is removed from whichever list it
is on.
186
APPENDIX H: Series II modem cables
Appendix H - Series II Modem Cables
These cables connect your Series II Modem to the serial port of your
terminal or computer serial port.
DB25 DTE Connector
DB25 DCE Connector
on Computer, etc.
on Modem
TD
2
3
2
3
4
5
6
7
8
TD
RD
RD
RTS
CTS
DSR
GND
CD
4
RTS
CTS
DSR
GND
CD
5
6
7
8
DTR
RI
20
22
20 DTR
22 RI
Figure I-1. RS232 Cable (IBM PC)
7
4
8-pin mini-DIN
8
6
1
5
3
2
TD
2
3
4
5
3
5
1
2
TD
RCV
Handshake Out
Handshake In
RCV
RTS
CTS
GND
7
4
8
GND
GND
Figure I-2. Mac Cable
187
SERIES II INTELLIGENT DATA/FAX MODEMS
The following cables are for 2-wire and 4-wire leased line connections using
screw connectors.
1
2
3
Red (Tip)
Green (Ring)
4
5
6
To Terminal-Block Screws
(Transmit and Receive)
RJ-11 plug
Figure I-3. Two Wire Leased Line Connection
Red
3
Transmit Pair
Receive Pair
Green
Yellow
Black
4
2
5
To Terminal-Block Screws
(Transmit and Receive)
RJ-11 plug
Figure I-4. Four Wire Leased Line Connection
(336+ [MD1640A] Only)
188
APPENDIX I: RS232C Interface Specifications
Appendix I - RS232C Interface Specifications
The Series II Modem's RS232C interface circuits have been designed to
meet the electrical specifications given in EIA (Electronic Industries
Association) RS232C standards. All signals generated by the modem are
approximately 10 volts when measured across a load of 3000 ohms or
greater. The receiving circuits of the modem will accept signals in the
3 to 25 volt range. The voltage thresholds are:
Negative = voltage more negative than –3 volts with respect to signal
ground
Positive = voltage more positive than +3 volts with respect to signal
ground
SIGNAL INFORMATION:
NEGATIVE
POSITIVE
Binary State
Signal Condition
Control and Timing Function
One
Mark
Off
Zero
Space
On
The input impedances of all modem circuits which accept signals from
the data processing terminal or CPU equipment have DC resistances of
4.7K. For more specific details, consult the EIA RS232C standard itself.
The following chart lists the EIA RS232C interface pins and circuits
present on the Series II Modem's RS232C Interface connector. All other
pins are unused.
Pin
No.
Abbrev. EIA
CCITT
Signal
Function
Circuit Circuit Source
1
2
3
4
5
6
7
8
PG
SD
--
101
103
104
105
106
107
102
109
--
--
Protective Ground
Transmitted Data
Received Data
Request to Send
Clear to Send
Data Set Ready
Signal Ground
Carrier Detect
Test Voltage
BA
BB
CA
CB
CC
AB
CF
+v
DTE
DCE
DTE
DCE
DCE
--
DCE
DCE
DCE
DCE
DCE
DTE
RD
RTS
CTS
DSR
SG
CD
+v
HS
9**
12
15*** TC
17*** RC
--
--
High Speed
DB
DD
CD
114
115
108/2
Transmit Clock
Receive Clock
Terminal Ready
20
TR****
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SERIES II INTELLIGENT DATA/FAX MODEMS
22
24
25
RI
XTC
OOS
CE
DA
CN
125
113
142
DCE
DTE
DTE
Ring Indicator
External Transmit Clock
Terminal Busy
** Pin 9 need not be present in your RS232C cable
*** Pins 15 and 17 are necessary only for synchronous operation
**** Also known as DTR (Data Terminal Ready)
The computer or terminal should be supplied with a cable terminated
with a Cinch DB25P (or equivalent) connector mounted in a Cinch
DB51226-1 (or equivalent) hood assembly as specified by the EIA
RS232C standard.
Functional Description of RS232C Signals:
Transmitted Data - Pin 2, SD (BA)
Direction: to modem
Signals on this circuit are generated by the customer's terminal and
transferred to the transmitter of the Series II Modem. A positive signal
is a space (binary 0) and a negative signal is a mark (binary 1). The
transmitting terminal should hold this line in the marking state when
no data is being transmitted, including intervals between characters or
words. The TRANSMIT (XMT) LED indicates the status of this circuit.
Received Data - Pin 3, RD (BB)
Direction: from modem
The lead is the data output of the modem. Data signals received from
the remote modem are presented on this line. When no carrier signal is
being received (pin 8 negative), this line will be forced into a marking
condition. The RECEIVE (RCV) LED indicates the status of this signal.
Request To Send - Pin 4, RTS (CA)
Direction: to modem
The RTS signal indicates to the modem that the computer or terminal
has data that it wants to transmit.
190
APPENDIX I: RS232C Interface Specifications
Clear To Send - Pin 5, CTS (CB)
Direction: from modem
The CTS line indicates to the terminal that the Series II Modem will
transmit any data present on the Transmit Data line (pin 2).
Data Set Ready - Pin 6, DSR (CC)
Direction: from modem
DSR On indicates that the Series II Modem is in the data mode and is
connected to the communications channel. This signal will be on
during analog-loop-test mode.
Signal Ground - Pin 7, SG (AB)
The SG lead is connected to signal ground of the modem. It establishes
the common ground reference for all other interface signals.
Data Carrier Detect - Pin 8, CD (CF)
Direction: from modem
DCD On (positive voltage) indicates that data carrier has been received
from the other modem. This circuit will not normally turn on in the
presence of message circuit noise or out-of-band signals. There is a one
second delay between when the carrier tone has been detected and
when the CD circuit is turned on.
This signal goes off if received data carrier falls below the receiver
threshold for more than 37 mSec. When CD is off, the Received Data
circuit (pin 3) is held to the marking state.
Test Voltage - Pin 9, XV
Direction: from modem
The XV lead has 330 ohms of resistance to +12 volts DC. This lead may
be used to strap other signals high. For example, if the terminal does
not supply a DTR (Data Terminal Ready) signal, Pin 9 may be jumpered
to Pin 20 (DTR) on the RS232 connector or in the cable to force DTR
on.
191
SERIES II INTELLIGENT DATA/FAX MODEMS
Transmit Clock - Pin 15, TC (DB)
Direction: from modem
The TC signal is provided only when the Series II Modem is used in the
synchronous mode. The clock is a square wave and is used to provide
the computer or terminal with timing information for its Transmit Data
circuit (pin 2). This clock will be provided on the interface at all times
when the modem is in Synchronous mode.
The first signal element of the Transmitted Data signal should be pre-
sented by the terminal on the first positive (Off to On) transition of TC
which occurs after the CTS circuit on pin 5 has turned on. The trans-
mitted data is sampled by the modem on negative transition of TC.
Receive Clock - Pin 17, RC (DD)
Direction: from modem
The RC signal has the same characteristic of Transmit Clock, with the
exception that it is used to provide the computer or terminal with
timing information for its Receive Data (pin 3) circuit. The negative
transition (On to Off) of RC indicates the center of each signal element
on the Received Data circuit.
Data Terminal Ready - Pin 20, TR or DTR (CD)
Direction: to modem
This signal (TR or DTR) provides a means for the terminal or computer
to control the modem's connection to the communications channel. A
high DTR signal is required by the modem to be able to communicate.
Turning DTR off for more than 50 mSec will force the modem to
disconnect.
The most common use of DTR is in automatic answer applications. A
high DTR signal is required by the modem to answer a call. A frequently
used method is to have the computer turn on DTR in response to RI
(Ring Indicator), which allows the modem to answer. Later, DTR is
192
APPENDIX I: RS232C Interface Specifications
turned off at the conclusion of the log off procedure, which forces the
modem to disconnect, enabling it to receive another call. In non auto
answer applications it is advisable to leave DTR on using the modem's
DIP-switch option. This is the standard factory setting. An alternative is
to provide a constant high DTR from the terminal or computer. The
Data Terminal Ready (DTR) LED indicates the status of this signal.
Ring Indicator - Pin 22, RI (CE)
Direction: from modem
This signal will remain on for the duration of the ringing signal. When a
ring signal is received by the modem, the modem will automatically
answer after the first ring. The modem will answer after a specified
number of rings which can be programmed in AT Command mode, but
if none is specified, the modem will answer after the first ring.
External Transmit Clock - Pin 24, XTC
Direction: to modem
Supplies the same function as transmit clock on Pin 15.
Terminal Busy (Out of Service) - Pin 25, OOS
Direction: to modem
The Terminal Busy (OOS) circuit is not defined in the RS232C
standard, but is used by us and most manufacturers to make the phone
lines busy to incoming phone calls. Pin 25 is not normally connected to
the RS232C interface when shipped from the factory; it can be ordered
connected as an option. If pin 25 is connected and is brought high, the
modem will be placed Off Hook, and busy to incoming calls.
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SERIES II INTELLIGENT DATA/FAX MODEMS
Appendix J - Regulatory Information
FCC and IC EMI/RFI Statements
When correctly installed and maintained, the modem will present no
hazard to the user. When correctly installed the modem will be
connected to the PSTN or a PW and to a Data Terminal Equipment
(DTE), whose modem connections comply with ITU recommendation
V28. The DTE connections are therefore taken to be safe voltages (less
than 30 volts).
This equipment generates, uses, and can radiate radio frequency energy
and if not installed and used properly, that is, in strict accordance with
the manufacturer’s instructions, may cause interference to radio
communication. It has been tested and found to comply with the limits
for a Class A computing device in accordance with the specifications in
Subpart J of Part 15 of FCC rules, which are designed to provide
reasonable protection against such interference when the equipment is
operated in a commercial environment. Operation of this equipment in
a residential area is likely to cause interference, in which case the user
at his own expense will be required to take whatever measures may be
necessary to correct the interference.
Changes or modifications not expressly approved by the party
responsible for compliance could void the user’s authority to operate
the equipment.
This digital apparatus does not exceed the Class A limits for radio noise emission
from digital apparatus set out in the Radio Interference Regulation of Industry
Canada.
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les
limites applicables aux appareils numériques de la classe A prescrites dans le
Règlement sur le brouillage radioélectrique publié par Industrie Canada.
194
APPENDIX J: Regulatory Information
FCC Part 68 Regulations for Telephone-Line
Interconnection
1. This equipment complies with Part 68 of the Federal Communica-
tions Commission (FCC) rules. On the outside surface of this
equipment is a label that contains, among other information, the
FCC registration number and ringer equivalence number (REN).
If requested, this information must be provided to the telephone
company.
2. As indicated on the next page, the suitable jack (Universal Service
Order Code connecting arrangement) for this equipment is
shown. If applicable, the facility interface codes (FIC) and service
order codes (SOC) are shown.An FCC-compliant telephone cord
and modular plug is provided with this equipment. This equipment
is designed to be connected to the telephone network or premises
wiring using a compatible modular jack which is Part 68 compliant.
See installation instructions for details.
3. The ringer equivalence number (REN) is used to determine the
quantity of devices which may be connected to the telephone line.
Excessive REN’s on the telephone line may result in the devices not
ringing in response to an incoming call. In most, but not all areas,
the sum of the REN’s should not exceed five (5.0). To be certain of
the number of devices that may be connected to the line, as
determined by the total REN’s, contact the telephone company to
determine the maximum REN for the calling area.
4. If this equipment causes harm to the telephone network, the tele-
phone company will notify you in advance. But if advance notice
isn’t practical, the telephone company will notify the customer as
soon as possible. Also, you will be advised of your right to file a
complaint with the FCC if you believe it is necessary.
5. The telephone company may make changes in its facilities, equip-
ment, operations, or procedures that could affect the operation of
the equipment. If this happens, the telephone company will
provide advance notice in order for you to make necessary
modifications in order to maintain uninterrupted service.
195
SERIES II INTELLIGENT DATA/FAX MODEMS
6. If trouble is experienced with this equipment (the model of which
is indicated below) please contact Black Box at the address shown
below for details of how to have repairs made. If the trouble is
causing harm to the telephone network, the telephone company
may request you remove the equipment from the network until the
problem is resolved.
7. No repairs are to be made by you. Repairs are to be made only by
Black Box. Unauthorized repairs void registration and warranty.
8. This equipment cannot be used on public coin service provided by
the telephone company. Connection to Party Line Service is subject
to state tariffs. (Contact the state public utility commission, public
service commission or corporation commission for information.)
9. If so required, this equipment is hearing-aid compatible.
Trade Names:
Model Number:
Series II Modem 336 and 336+
Series II Modem 336: MD1641A
Series II Modem 336+: MD1640A
AU7USA-20673-MM-E
0.3B
FCC Registration #:
Ringer Equivalence:
Modular Jack (USOC):
Service Center in USA:
RJ11C or RJ11W (single line)
Black Box Corp.
1000 Park Dr.
Lawrence, PA 15055-1018
U.S.A.
Phone: (724) 746-5500
Fax: (724) 746-0746
Email: [email protected]
WWW: www.blackbox.com
196
APPENDIX J: Regulatory Information
Canadian Limitations Notice
Notice: The ringer equivalence number (REN) assigned to each
terminal device provides an indication of the maximum number of
terminals allowed to be connected to a telephone interface. The
termination of a interface may consist of any combination of devices
subject only to the requirement that the sum of the ringer equivalence
numbers of all the devices does not exceed 5.
Notice: The Industry Canada label identifies certificated equipment.
This certification means that the equipment meets certain telecommu-
nications network protective, operational and safety requirements. The
Industry Canada does not guarantee the equipment will operate to the
user’s satisfaction.
Before installing this equipment, users should ensure that it is permissi-
ble to be connected to the facilities of the local telecommunications
company. The equipment must also be installed using an acceptable
method of connection. The customer should be aware that compliance
with the above conditions may not prevent degradation of service in
some situations.
Repairs to certified equipment should be made by an authorized
Canadian maintenance facility designated by the supplier. Any repairs
or alterations made by the user to this equipment, or equipment
malfunctions, may give the telecommunications company cause to
request the user to disconnect the equipment.
Users should ensure for their own protection that the electrical ground
connections of the power utility, telephone lines and internal metallic
water pipe system, if present, are connected together. This precaution
may be particularly important in rural areas.
Caution: Users should not attempt to make such connections them-
selves, but should contact the appropriate electric inspection authority,
or electrician, as appropriate.
197
© Copyright 2000. Black Box Corporation. All rights reserved.
1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax 724-746-0746
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