USER
MANUAL
MODEL 1025
and 1025S
Synchronous Short
Range Modem with
Clocking Options
SALES OFFICE
(301) 975-1000
Part #07M1025-C
Doc. #041012UC
Revised 4/20/98
TECHNICAL SUPPORT
(301) 975-1007
C
E
R
T
I
F
I
E
D
An ISO-9001
Certified Company
2.0 GENERAL INFORMATION
3.0 CONFIGURATION
Thank you for your purchase of this Patton Electronics product.
This product has been thoroughly inspected and tested and is warrant-
ed for One Year parts and labor. If any questions or problems arise
during installation or use of this product, please do not hesitate to con-
tact Patton Electronics Technical Support at (301) 975-1007.
The Model 1025 provides six configuration switches which allow
selection of clocking method, RTS/CTS delay and data rate. This sec-
tion describes switch locations and explains all possible switch config-
urations.
3.1 SWITCH LOCATIONS
2.1 FEATURES
For your convenience, all configuration switches are located on a
SIP (single in-line package) mounted on the PC board. Figure 1
shows the location of the SIP with respect to other PC board compo-
nents. For instructions on opening the Model 1025 case, see Section
4.1.2.
• Supports data rates to 19.2 Kbps
• Internal, external or receive loopback clocking
• Transformer isolation guards against ground looping
• Range to 11 miles
Terminal
Block
Isolating
Transformers
• Operates full duplex over two unconditioned twisted pair
• Customized VLSI chip with separate filter for each data rate
• No AC power or batteries required
X X X X
P E 0 6 8
N O T P A T
• Miniature size
Control
Switches
Patton
VLSI chip
• Silicon Avalanche Diode surge protection (Model 1025S)
2.2 DESCRIPTION
The Patton Electronics Model 1025 miniature, synchronous
short range modem uses the latest in VLSI technology to combine
high-quality data transmission with compact size. The Model 1025
does not require any AC power or batteries to operate, and communi-
cates up to 11 miles in point-to-point environments. For maximum flex-
ibility, the Model 1025 supports three clocking options: internal, exter-
nal or receive loopback.
Figure 1. Model 1025 PC board showing switches
Figure 2 shows the orientation of the configuration switches,
including ON/OFF position.
OFF
Providing full duplex transmission over two twisted pair, the Model
1025 accommodates seven switch selectable data rates from 1200 to
19,200 bps. The Model 1025’s custom VLSI chip uses a separate filter
for each data rate, rather than a single “compromise” filter.
1
2
3
4
5
6
Transformer isolation allows the Model 1025 to operate between build-
ings without data disruption due to ground potential differences.
ON
Figure 2. Close-up of configuration switches
The Model 1025S is a surge protected version of the Model 1025,
incorporating Silicon Avalanche Diodes that provide 600 watts of pro-
tection per wire.
3.2 SWITCH SETTINGS
Switches 4, 5 and 6: Data Rate
All possible settings for the Model 1025’s configuration switches
are presented in the summary table and descriptions below. If you
have additional questions regarding configuration, contact Patton
Technical Support at (301) 975-1007.
Switches 4 thru 6 are set in combination to allow the Model 1025
to be used at data rates from 1.2 to 19.2 Kbps.
Switch 4
On
Switch 5
On
Switch 6
On
Setting
1.2 Kbps
On
On
Off
On
Off
Off
Off
On
Off
On
Off
On
Off
Off
Off
On
On
Off
Off
On
Off
2.4 Kbps
4.8 Kbps
7.2 Kbps
9.6 Kbps (Default)
14.4 Kbps
19.2 Kbps
19.2 Kbps
SWITCH SUMMARY TABLE
Position
Switch 1
Switch 2
Switch 3
Switch 4
Switch 5
Switch 6
Function
Transmit Clock
Transmit Clock
RTS/CTS delay
Data Rate
Factory Default
Off
On
On
On
Off
Off
Internal
Clock
}
7 mSec delay
9,600 bps
Data Rate
}
Data Rate
Switches 1 and 2: Transmit Clock
Switches 1 and 2 are used together to specify the clocking
method. The Model 1025 can provide an internal clock (Pin 15),
receive an external clock (from Pin 24), or loopback a received clock.
Switch 1
On
Switch 2
On
Setting
External Clock
On
Off
External Clock
Off
Off
On
Off
Internal Clock (Default)
Receive Loopback
Switch 3: RTS/CTS Delay
After request to send (RTS) is raised by the host terminal, the
Model 1025 raises CTS after a delay in order to give the remote termi-
nal time to receive an incoming signal. Depending on the type of envi-
ronment, either a 7mS or 53mS delay can be selected.
Switch 3
On
Setting
7 mS (Default)
53 mS
Off
4.0 INSTALLATION
When connecting two Model 1025s, it is necessary to use a
“crossover” cable. The diagram below shows how a crossover cable
should be constructed for an environment where both Model 1025s
use a 6-wire RJ-11 connector. Similar logic should be followed when
using RJ-45 connectors or a combination of the two.
Once the Model 1025 is properly configured, it is ready to connect
to your system. This section tells you how to properly connect the
Model 1025 to the twisted pair and RS-232 interfaces, and how to
operate the Model 1025.
SIGNAL PIN#
COLOR
COLOR PIN#
SIGNAL
4.1 CONNECTION TO THE TWISTED PAIR INTERFACE
GND†
RCV◊
XMT
XMT
RCV
GND
1
2
3
4
5
6
Blue‡ ................White
Yellow ..............Red
Green...............Black
Red..................Yellow
Black................Green
White ...............Blue
6
4
5
2
3
1
GND
XMT
RCV
RCV
XMT
GND
The Model 1025 supports data-only communication between two
RS-232 devices at distances to 11 miles and data rates to 19.2 Kbps.
There are two essential requirements for installing the Model 1025:
1. These units work in pairs. Therefore, you must have one Model
1025 at each end of a two twisted pair interface.
†Connection to ground is optional
2. To function properly, the Model 1025 needs two twisted pairs of
metallic wire. These pairs must be unconditioned, dry metallic
wire, between 19 and 26 AWG (the higher number gauges may
limit distance somewhat). Standard dial-up telephone circuits, or
leased circuits that run through signal equalization equipment, are
not acceptable.
‡Standard color codes—yours may be different
◊
The Model 1025 is not sensitive to polarity
1 - Blue
2 - Orange
3 - Black
4 - Red
1 - Blue
2 - Yellow
3 - Green
4 - Red
5 - Green
6 - Yellow
7 - Brown
8 - Slate
For your convenience, the Model 1025 is available with three dif-
ferent twisted pair interfaces: RJ-11 jack, RJ-45 jack and terminal
blocks with strain relief.
5 - Black
6 - White
Standard AT&T color codes
4.1.1 TWISTED PAIR CONNECTION USING RJ-11 OR RJ-45
The RJ-11 and RJ-45 connectors on the Model 1025’s twisted pair
interface are pre-wired for a standard TELCO wiring environment. The
signal/pin relationships are shown below:
4.1.2 TWISTED PAIR CONNECTION USING TERMINAL BLOCKS
If your application requires you to connect two pairs of bare wires
to the Model 1025, you will need to open the case to access the termi-
nal blocks. The instructions on the following pages will tell you how to
open the case, connect the bare wires to the terminal blocks, and fas-
ten the strain relief collar in place so that the wires won’t pull loose.
RJ-11
SIGNAL
RJ-45
SIGNAL
1...................GND†
2...................RCV‡
3...................XMT
4...................XMT
5...................RCV
6...................GND
1 .................N/C
2 .................GND†
3 .................RCV‡
4 .................XMT
5 .................XMT
6 .................RCV
7 .................GND
8 .................N/C
†Connection to ground is optional
‡The Model 1025 is not polarity sensitive
1. Open the unit by gently inserting a screwdriver between the
DB-25 connector and the lip of the plastic case (see below).
You don’t have to worry about breaking the plastic, but be
careful not to bend the D-sub connector.
4. Connect one pair of wires to the two XMT (transmit) poles on
the terminal block. The Model 1025 is not polarity sensitive,
so either wire may connect to either pole.
5. Connect the other pair of wires to the two RCV (receive) poles
on the terminal block. The Model 1025 is not polarity sensi-
tive, so either wire may connect to either pole.
Ultimately, you will want to construct a two pair crossover
cable that makes a connection with the two Model 1025s as
shown below:
XMT
XMT
G
RCV
RCV
RCV
RCV
G
XMT
XMT
One Pair
One Pair
}
}
To Shield (Optional)
6. If there is a shield around the telephone cable it may be con-
nected to “G” on the terminal block. To avoid ground loops,
we recommend connecting the shield at the computer end
only. A ground wire is not necessary for proper operation of
the Model 1025.
7. When you finish connecting the wires to the terminal block,
the assembly should resemble the diagram below:
Once the unit has been opened, you will be able to see the
terminal blocks located at the rear of the PC board.
2. Strip the outer insulation from the twisted pairs about one inch
from the end.
3. Strip back the insulation on each of the 2 twisted pair wires
about .25”.
8. Place the 2 halves of the strain relief assembly on either side
of the telephone wire and press together very lightly. Slide the
assembly so that it is about 2 inches from the terminal posts
and press together firmly. If your cable diameter is too small
or too large for our strain relief, please contact our technical
support. We have strain relief assemblies to accommodate
most cable diameters.
10. Place the top half of the case as necessary to slide it over the
strain relief assembly. Do not snap the case together yet.
11. Insert one captive screw through a saddle washer. Then
insert the entire piece through the hole in the DB-25 end of
the case. Snap that side of the case closed. Repeat the
process for the other side. This completes cable installation.
4.2 CONNECTION TO THE RS-232 INTERFACE
9. Insert the strain relief assembly and wire going into the slot in
the bottom half of the modem case and set it into the recess
in the case.
Once you have connected the twisted pair wires correctly, simply
plug the Model 1025 directly into the DB-25 port of the RS-232 device.
After doing so, remember to insert and tighten the two captive connec-
tor screws.
4.2.1 CONNECTION TO A “DTE” DEVICE
The Model 1025 is wired as a DCE, and therefore wants to plug
into a DTE such as a terminal, PC or host. Because the Model 1025 is
interface powered, a direct connection to the RS-232 DTE port is most
desirable. If you must use a cable to connect the Model 1025 to the
DTE port, make sure it is a straight through cable of the shortest possi-
ble length—we recommend 6 feet or less.
APPENDIX A
SPECIFICATIONS
4.2.2 CONNECTION TO A “DCE” DEVICE
Since the Model 1025 is wired as a DCE, you cannot connect it
directly to another DCE such as a modem, multiplexer or printer. If you
need to connect the Model 1025 to another DCE device, you must use
a null modem cable wired according to diagram below. We recom-
mend that the cable is as short as possible, preferably 6 feet or less.
Transmission Format: Synchronous, full duplex
Transmission Line: Two unconditioned twisted pair 19 - 26 AWG
Clocking: Internal, external or receive loopback
Range: (See table below)
Connection to Model 1025†
DB-25 Pin No.
Connection to DCE Device
DB-25 Pin No.
Interfaces: EIA RS-232, CCITT V.24
1......................................................1
Data Rates: 1.2 - 19.2 Kbps
2......................................................3
3......................................................2
4......................................................8
8......................................................4
6....................................................20
20......................................................6
17....................................................24
24....................................................17
7......................................................7
Isolation: Minimum 1500 V RMS via custom transformers
Surge Protection: 600W Surge Protection (10x1000µs waveform)
(Model 1025S)
Control Signals: CTS turns on 8 or 53 mS (switch selectable) after
the terminal raises RTS; DSR and DCD are constantly on
Connectors: DB-25 male or female on RS-232 side; RJ-11, RJ-45 or
†Note: When connecting to another DCE device, the Model 1025
should be configured for “external clock” (see Section 3.2).
terminal block with strain relief on line side
Power Supply: No external power required; uses power from EIA
data and control signals
4.3 OPERATING THE MODEL 1025
Temperature Range: 0-60°C (32-140°F)
Altitude: 0-15,000 feet
Once the Model 1025 is properly configured and installed, it should
operate transparently—as if it were a standard cable connection.
Operating power is derived from the RS-232 data and control signals;
there is no “ON/OFF” switch. All data signals from the RS-232 inter-
face are passed straight through. All control signals from the RS-232
interface are looped back.
Humidity: Up to 95% non-condensing
Dimensions: 2.66” x 2.10” x 0.73”
Weight: 2 oz.
Note: If your system requires hardware flow control, you will need
the Patton Model 1030 or Model 1070 Short Range Modem. Call
Patton Customer Service at (301) 975-1007 for more information.
Model 1025 Distance Table (miles)
Wire Gauge
Data
Rate
19
7.5
10.0
10.0
10.0
11.0
24
3.5
3.5
7.0
8.5
8.5
26
2.5
2.5
4.0
5.0
6.0
19,200
9,600
4,800
2,400
1,200
APPENDIX B
RS-232 PIN CONFIGURATIONS
DIRECTION
“DCE” STANDARD SETTING
DIRECTION
1- (FG) Frame Ground
2- (TD) Transmit Data
3- (RD) Receive Data
4- (RTS) Request to Send
5- (CTS) Clear to Send
6- (DSR) Data Set Ready
7- (SG) Signal Ground
To Model 1025
From Model 1025
To Model 1025
From Model 1025
From Model 1025
Transmitting Timing - 15
Receiver Timing - 17
From Model 1025
From Model 1025
To Model 1025
To Model 1025
Data Term. Ready (DTR) - 20
Transmitting Timing (LXC) - 24
8- (DCD) Data Carrier Detect From Model 1025
Copyright © 1998
Patton Electronics Company
All Rights Reserved
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