Rs-485; Figure 10: Rs-485 Topology - CipherLab 5000 Hardware Manual

1.3.12 RS-485

A standard RS-485 port is also available on the JP3 to constitute multi-station
systems. Though it is simple and low cost, care must be taken to ensure proper
operations.
The data rate is 125 kbps.
Compatible to CipherLAB 510, 520 and so on.
Maximum network run length is 1000 meters
No fork, nor star connections. As depicted below, connections b, d & f are
acceptable but not others.

Figure 10: RS-485 topology

Use AWG 22, shielded twist cables or Cat 5 UPT cables.
Terminators help to absorb reflections and should be placed at both "physical"
ends. A slide switch turns on/off an on-board termination circuitry.
For the RS-485 network to work properly, a unique station ID has to be assigned
to each terminal first.
18
Introducing 5000/5100:
Features