Specifications

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9.1. CPU to Emergency Signaling
External input control is available to trigger a tone signal from the PCM over the paging system. Shorting EM/SC to
the GND terminal will produce a user-programmed tone into a specific zone group.
This feature is typically used to signal shift changes using a contact closure pair from an external master clock. The
tone signal can be directed to a specific group of zones by programming them into the EM/SC zone group.
The length and type of tone can also be programmed as well. A Follow Contact programming option allows the tone
to be emitted for as long as the external contacts remain closed.
See System Programming, Section 11 for information on programming the EM/SC feature.
9.2. CPU to Re-Synch (Master Clock)
The PCM system contains a real time clock that is used to control the trigger for up to 8 separate "Time Tones". In
order to ensure that the PCM will remain in sync with external master clocks, a Re-Synchronization feature is
provided.
Shorting the AUX and GND terminals together will reset the real time clock to a predetermined time. By
programming this time so that it coincides with the time of a master clock contact closure, the PCM will be re-
synchronized with the master clock.
The time of day of the re-synchronization must first be programmed into the PCM and the feature enabled for this
feature to work. See System Programming, Section 11 for further information on this function.
9.3. Relay Drivers
Each zone module has three relay driver output terminals - RD A, RD B, and RD C - one for each speaker zone.
When a zone is active, its associated relay driver is shorted to the RD COM terminal through an open collector
transistor (see Figure 9-1). These drivers can be used to activate external equipment or relays.
IMPORTANT: These outputs are not contact closures and have specific voltage and current requirements. The power
supply for these relays must be 12V DC or less. The total sink current per driver cannot exceed 100mA.
NOTE
: Some power supplies are rated at 12V DC, but when lightly loaded, are considerably higher in output
voltage. If the power supply for the relay has an unloaded output of greater than 13V DC, the relay drivers may begin
to conduct, thereby energizing the relay. If this problem occurs, you can either replace the supply with a regulated
supply, or use a lower voltage supply.
9. Optional Wiring