Specifications

Table Of Contents
ARCnet156
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6.0 ARCNET156
6.1 ARCnet156 CMnet Components
The SSWEB-Liebert gateways and control modules communicate using ARCnet156, a token-passing
protocol running at 156 Kbps. ARCnet156 requires network boards to properly terminate, bias, pro-
tect and repeat data transmitted over the twisted pair EIA-485 segment.
An ARC156-Kit should be used for every gateway module. The kit filters out some signal noise and
provides diagnostic information about the ARCnet156 network. Two 120 ohm terminators are
included with each ARC156-Kit.
6.2 Segment Requirements
An ARCnet156 segment is an arrangement of gateways, control modules and ARCnet156 devices up
to 2,000 ft. (610m) long.
A segment must:
Be wired in a daisy chain (see Figure 20).
Have an ARC156-KIT installed in the middle of the segment.
Have a PROT485 installed at each building entrance and exit.
Have one ARC156-KIT for every 32 modules and each 2,000 ft. (610m) of equipment and cabling.
Not exceed 50 modules including ARCnet enhancement devices.
Have a 120 ohm terminator at each end unless the segment is less than 10 ft. (3m) long.
Figure 20 Acceptable daisy chain configurations
NOTE
Each segment must use a Magnum ARC cable.
Term
Term
Term
Term
Configuration A Configuration B