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CHAPTER 4: Installation
4.2 Wiring For Multipoint Circuits
The Modem supports multipoint applications using either a star or daisychain
topology. Both topologies require special wiring, as well as specific DIP-switch
settings for master and slave units.
4.2.1 D
AISYCHAIN
T
OPOLOGY
Using a daisychain topology, you may connect as many as 10 Async Short-Haul
Modem MPs together in a master/slave arrangement. Maximum distance between
the units will vary based upon the number of drops, data rate, wire gauge, etc. Call
Technical Support for specific distance estimates.
Figure 4-2 shows how to wire the two-pair cables properly for an Async Short-Haul
Modem MP daisychain topology. Note that the ground connection is not needed.
Figure 4-2. Daisychain wiring.
HOST
FIRST SLAVE
OTHER SLAVE(S)
XMT+.........................RCV+ ...........................RCV+
XMT-..........................RCV- ............................RCV-
RCV+.........................XMT+ ...........................XMT+
RCV-..........................XMT- ............................XMT-
In a multipoint topology, you must configure the master Async Short-Haul Modem
MP’s DIP switches differently than those of the slave Modems. These are the
proper DIP-switch settings for a daisychain topology:
Switch Number
1
2
3
4
5
6
7
Master Positions
ON
ON
ON
OFF
OFF
OFF
OFF
Slave Positions
ON
ON
ON
OFF
OFF
OFF
ON
