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Model 300MB-SD CommCenter Series D1
Federal Signal
www.fedsig.com
Recommendation for the Signal Lines
Recommendation for the Signal Lines
REDUCED SOUND OUTPUT: If too small a diameter cable is used, unacceptable
signal voltage drop in the signal line will cause reduced sound output from
the remote signal device. Only use a cable having wire diameter greater than
22 AWG.
The signal lines transfer tone signals and verbal messages from the CommCenter
to the remote SelecTone
®
devices. To reduce the possibility of cross talk, hum, and
static-noise pickup, the signal lines must be twisted-pair, shielded audio cable. In
the majority of systems, use AWG 18 twisted-pair audio cables. Federal Signal does
not recommend that new or existing telephone lines be used as signal lines in a
SelecTone system for the following reasons:
• Interference from other services or systems, or interference from the system to
other services
• Cross talk, interference, or hum induced by other telephone lines
• Extended downtime because of the second-party involvement required to service
the lines
• The additional cost of installation, interfacing devices, and monthly charges as
opposed to a one-time cost of performing the installation
Connecting Signal Lines
CROSSTALK INTERFERENCE: Mixing signal lines with power lines could
cause electrical interference, which could impede or render the system
inoperable.
SHOCK HAZARD:
Do not install signal lines in the same conduit with power lines.
Avoid routing signal lines on cable trays with high voltage power lines.
To connect the signal lines of the SelecTone system to the 300MB, connect a color-
coded, twisted pair of audio cables with conductors no smaller than 18 AWG to
the TB1-13 and TB1-14 terminals on TB1. Before using TB1-13 and TB1-14, remove
the labeled jumper. Every remote SelecTone signaling device in the system can be
connected in parallel or series to these lines. See Figure 2.
