The main supply unit is an electronic device containing a supply source, additional control circuits and input and output amplifiers. CPS 318 additionally contains a 4-channel intrared transmitter.
A main supply unit can be connected to a conference microphone system (up to 80 microphones), interpreter consoles (up to 10), main technical console, a recorder, external dynamic microphones or link signal (e.g. from an external mixing console). In addition to that, CPS 318 has two output connectors for infrared transmitters -- in case more then 4 channels are needed, it is possible to use a 10-channel infrared transmitter.
The main supply unit also has a light version (CPS 318 LIGHT) without an infrared transmittors and connectors for interpreter devices.