Installation, Twisted Pair Wiring Overview

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.

Powered Async. Short	Made In The USA
Powered Async. Short
Range Modem
	RX+ RX- GND TX- TX+

Power

RS-232 Interface

Line

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:

XMT		RCV	}One Pair
XMT		RCV	}One Pair
G	To Shield (Optional)	G	}One Pair
RCV		XMT
RCV		XMT

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.

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-11SIGNAL

1GND†

2RCV

3XMT

4XMT

5RCV

6GND

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

1 - Blue

2 - Yellow

3 - Green

4 - Red

5 - Black

6 - White

AT&T standard modular color codes