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.
SIGNAL
PIN#
COLOR
COLOR
PIN#
SIGNAL
GND
†
1
Blue
‡
................White
6
GND
RCV
◊
2
Yellow ..............Red
4
XMT
XMT
3
Green...............Black
5
RCV
XMT
4
Red ..................Yellow
2
RCV
RCV
5
Black ................Green
3
XMT
GND
6
White ...............Blue
1
GND
†
Connection to ground is optional
‡
Standard color codes—yours may be different
◊
The Model 1025 is not sensitive to polarity
Standard AT&T color codes
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.
4.0 INSTALLATION
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.
4.1 CONNECTION TO THE TWISTED PAIR INTERFACE
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.
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.
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.
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:
RJ-11
SIGNAL
RJ-45
SIGNAL
1...................GND
†
1 .................N/C
2...................RCV
‡
2 .................GND
†
3...................XMT
3 .................RCV
‡
4...................XMT
4 .................XMT
5...................RCV
5 .................XMT
6...................GND
6 .................RCV
7 .................GND
8 .................N/C
†
Connection to ground is optional
‡
The Model 1025 is not polarity sensitive
7
8
1 - Blue
2 - Yellow
3 - Green
4 - Red
5 - Black
6 - White
1 - Blue
2 - Orange
3 - Black
4 - Red
5 - Green
6 - Yellow
7 - Brown
8 - Slate
