4.0 INSTALLATION
The Model 1070 is easy to install. After configuring the DIP
switches and DCE/DTE switches, connect the two twisted pairs using
one of two methods: terminal blocks or RJ-11 jack. Figure 3 (below)
shows the location of the terminal blocks and RJ-11 jack, as well as the
female DB-25 on the rear of the Model 1070.
Figure 3.
Rear view of 1070 showing interface connectors
4.1 TWISTED PAIR WIRING OVERVIEW
These short range modems are designed to work in
pairs
. You will
need one at each end of a 4-wire twisted pair circuit. The pairs must be
"dry" (unconditioned) metallic wire, 19 - 26 AWG. The smaller gauges
limit distance somewhat compared with larger gauges. When you have
completed wiring for your data circuit, the pin connections should be as
shown below:
4.1.1 TWISTED PAIR CONNECTION USING TERMINAL BLOCKS
If your two twisted pair line terminates in bare wires, strip the ends
and connect the individual leads to each Model 1070's terminal block.
Be sure the end-to-end connections follow the diagram above.
7
XMT RCV
XMT RCV
G
G
RCV XMT
RCV XMT
To Shield (Optional)
}
One Pair
}
One Pair
RS-232 Interface
Made In The USA
Line
Power
RX+ RX- GND TX- TX+
Powered Async. Short
Range Modem
4.1.2 TWISTED PAIR CONNECTION USING RJ-11
If your two-pair cable is terminated in an RJ-11 plug, you may use
the RJ-11 jack in the back of the Model 1070 to make the connection.
The RJ-11 jack on a Model 1070 series Short Range Modem is
prewired for a standard TELCO wiring environment. To be sure you
have the right wiring, use the diagram below as a guide.
RJ-11
SIGNAL
1
GND
†
2
RCV
3
XMT
4
XMT
5
RCV
6
GND
For proper signal crossing between two Model 1070s using RJ-11
connectors, pin-out the twisted pair cable according to the diagram
below. The Model 1070 is not sensitive to polarity, so other
configurations may work.
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
AT&T standard modular color codes
8
1 - Blue
2 - Yellow
3 - Green
4 - Red
5 - Black
6 - White
