The CP3 card is a 64-bit quad-core ARM Cortex-A72 processor running Linux operating system.
The purpose of the CP3 board is to execute the CP software, and to hold the configuration file which stores call numbers, privilege settings etc.

The CP3 board is located anywhere in the board 19’’ magazine, but will typically be inserted just beside the PSU2.

The CP3 has its operating system stored in a write protected partition of the SD card, meaning that it is not possible to destroy the operating system, and if tried to, a reboot will restore to the factory OS.