Black Box ME475A-R2, Manual

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Black Box Short Range Modem
Figure 3.
Rear view of ME475A-R2 - AC Power
3.1 TWO-WIRE INSTALLATION
When communicating over a single twisted pair circuit, the ME475A-R2 operates half
duplex: that is, it transmits in only one direction at a time. This method of operation is
effective for both point-to-point and multipoint applications.
In single-pair point-to-point applications, you will need a pair of ME475A-R2s for each
circuit—one at each end of the single pair wire. In single-pair multipoint applications
you will need three or more ME475A-R2 units. These can be connected using a star
topology, although a daisy chain topology is usually used.
Two-Wire Cable Connection Via RJ-45
1. The RJ-45 jack on a ME475A-R2 Short Range Modem is pre-wired for a stan-
dard TELCO wiring environment. To be sure you have the right wiring, use the
table below as a guide.
† Connection to ground is optional
2. Proper wiring of pairs between the two modems is as follows:
RJ-45 Signal
1 ------------------ NC
2 ------------------ GND†
3 ------------------ RCV
4 ------------------ XMT
5 ------------------ XMT
6 ------------------ RCV
7 ------------------ GND
8 ------------------ NC
RS-232 Interface (Female)
Made In the USA
Line
RX+ RX- GND TX- TX+
12V, 2A