GAI-Tronics 12580-001 Audio Distribution Module - Manual (Page 2)

Pub. 42004-600L2C
Model 12580-001 Amplifier Distribution/Monitor Module Page: 2 of 17
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The ADM’s contact closure inputs are typically used to monitor the amplifier failure contacts of the
central amplifiers to determine amplifier failure. Figure 1 illustrates a typical application for one paging
zone. Figure 2 illustrates an alternate application for one central amplifier and twelve speaker loops.
N OTE : (*) indicates that fault detection occurs only while the associated amplifier is not in use.
Figure 1. Single Page Zone - Typical Application
The ADM is comprised of two subassemblies: the 69250-xxx Distribution/Monitor printed circuit board
assembly (PCBA) and the 69248-xxx Central Processing Unit (CPU) PCBA. The ADM mounts in a
Snaptrack
™, a grooved plastic channel that allows a PCBA to securely ‘snap’ into place. The
Snaptrack
™ provides flexible installation because it may be installed in an equipment rack wherever it is
convenient.
The ADM communicates with the MCU via the CPU PCBA over a bi-directional RS-485 link. The CPU
PCBA monitors the status of the module’s contact closure inputs and speaker loop inputs and reports
them to the MCU via this communication link.
The MCU periodically interrogates the ADM to determine its status. The MCU identifies a particular
module on this RS-485 link by its address. (The ADM’s module address is set by rotary hex switch S1,
located on the CPU PCBA.)