- Bogen microprocessor module for PCM zone paging system- One required per system - Provides power data and audio connections for the PCM system- Connected to other PCM modules electrically through internal cables- Modules mechanically joined by sliding together interlocking tabs and securing with a screw on the rear panel- Designed to be wall-mounted with modules side by side like books (oriented so that when the blue connector blocks are on bottom PCM-TIM is far left PCM-CPU is first from left and the