Part of an intercom system that the headset or handset is connected to. Usually contains a volume control, a call button, indicator lights, a microphone on/off button, belt clip, and 3-pin XLR connectors used to connect the beltpack to the rest of the intercom system. The system can be part of a wireless system as well. In this case it would also contain transmitter and receiver components and batteries. Not to be confused with bodypack.