PCMCPU is the microprocessor module for the Bogen PCM Zone Paging System. One module is required per assembly (up to three PCMZPM zone modules). The PCMCPU module provides power, data and audio connections for the PCM system. PCMCPU module is connected to other PCM modules electrically through internal cables. Modules are mechanically joined by sliding together interlocking tabs and securing with a screw on the rear panel. The system is designed to be wallmounted with the modules side by side like books on a shelf, the PCMTIM is far left, the PCMCPU is first from left and the (first) PCMZPM module is on the right.