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The 4003 SIGcard is a four-circuit repeater.  It supervises each circuit for shorts 
and opens, and transfers a common trouble relay.  If a circuit is shorted, the 
SIGcard does not energize that relay.  The SIGcard is controlled and monitored 
by the 565-358 Voice Controller Assembly, or by a wired NAC circuit from the 
host panel. 
 
The Voice Controller Assembly, 4003 SIGcard, and 75W Amplifier Board 
Assembly receive power from the 4003 Power Supply.  This power supply can 
provide adequate power for the system cards and charge system batteries rated at 
up to 18 Ah.  Brownout and battery supervision are provide. Trouble conditions 
are monitored by the Voice Controller Assembly.  Termination’s are provided 
for external battery input.  However, in this "external battery configuration", the 
4003 charger is disabled. 
 
Speaker power is provided by the VCP Amplifier module, a 25V RMS amplifier 
with a rating of 75W at 25V only.  The "Class A/Music" features associated with 
4100 Audio Systems are not available with the VCP. 
 
Additional Descriptions 
4003 SIGcard Description 
4003 Power Supply 
Description 
VCP Amplifier Description