Installation manual

INSTALLING AN INTERCOM SYSTEM
When considering how to install and wire an intercom system, several factors must be taken into ac-
count. These include the number of stations, the length of the cable runs and whether single or multi-
ple channels are required. If multi-channel stations are connected with multi-pair cables, then crosstalk
becomes an important issue. Crosstalk is not a factor with single-channel systems or multi-channel
systems where each channel is run on its own individual cable to single-channel Remote Stations.
While the physical considerations include ease of installation, type of cabling, station location, etc., the
electrical considerations are concerned primarily with the capacitance between conductors on the inter-
com line, and the DC resistance in the ground return of the intercom line.
NOTE
: PIN 1 and the shell of the XLR plug on the interconnect cables should NOT be
connected together.
Excessive resistance in the conductors of the cable results in a loss of sidetone null at Remote Sta-
tions, and some overall loss of level. Excessive resistance in the ground conductor or shield greatly
increases crosstalk between channels. This can significantly affect the performance of multi-channel
systems.
Single-Channel System
In a single-channel system, there are two general methods of wiring Remote Stations to the Power
Supply. Any one method may be used exclusively in a small system, and both may used in various
combinations for a larger system.
1
Daisy Chain:
Remote stations are wired from one station to the next and so on along each
line connected to a Main Station. This requires the least amount of cable, but may be impracti-
cal due to the system layout. Also, if a break occurs in the line, all stations down line of the
break will be disconnected from the party line.
2
Hub, Star or Home Run:
Each Remote Station is wired directly back to a Main Station or to a
split of a line wired directly to a Main Station.
Channel AChannel A
Clear-Com System Installation Manual
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