5
2.3 Audio Station Wiring
Up to 7 audio stations can be connected to the PC4936 Audio Interface mod-
ule. Each station must be home-run to the interface module via a shielded 22
gauge, 4 wire cable. Each PC5921 can be up to 1000’/303m from the PC4936;
each PC5904 can be up to 500’/151.5m from the PC4936.
Connect each station to power (red - AUX, black - COM) and to the proper
audio connections on the PC4936 module (yellow - speaker, green - micro-
phone). Connect the drain wire of the shield to the COM terminal on the
PC4936 module or the black terminal of the station (make sure the drain
wire of the shield does not short anything on the back of the board), but not
both. Refer to the diagram below:
Avoiding Audio Station Interference Noise
The Combus wiring and several different electrical devices (fluorescent
lighting, etc.) may induce noise onto the intercom wires. For this reason
shielded wire should be used whenever possible. If shielded wire is not
used, each intercom wire must be spaced a minimum of 4 ft./1.2 m from all
Combus wiring, electrical wiring, fluorescent lighting and other sources of
electrical interference. If this is not possible, shielded wire must be used
with the drain of the shield connected as indicated in the above diagram.
firealarmresources.com