Chime Com 2 Set includes a door station (CC-DA) and a master stations (CC-1M). Additional masters may be added. Each master requires a separate power supply, the PT-1210N. The door station calls the master(s) by pressing a call button that initiates a chime. Communication is is Push to talk/release to listen at the master and hands free at the door station. Communication times out after being idle for twenty seconds. The master also has chime and voice volume controls and the door station features an illuminated call button.