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CHAPTER 4: Installation
4. Installation
The Async Short-Haul Modem MP is easy to install. After configuring the DIP
switches and DCE/DTE switches, connect the two twisted pairs using either
terminal blocks or the RJ-11 jack. Figure 4-1 shows the location of the terminal
blocks and RJ-11 jack, as well as the female DB25 connector.
Figure 4-1. Rear view of Modem 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 to 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 +
XMT - ------------------------------------------- RCV -
G ----------To Shield (optional)
G
RCV - ------------------------------------------- XMT -
RCV + ------------------------------------------- XMT +
RX+ RX- GND TX+ TX+
RS-232 Interface
Line
Power
}
One Pair
One Pair
}
