This communication systems control C-6533 ( )/ARC provides an intercommunication capability between the pilot and gunner. Two of the panels are installed in the helicopter. The system is used for intercommunication and radio control. It may be used in any one of three different modes as determined by the setting of the switches and controls on the panel. The three modes of operation are: Two way radio communication, radio receiver monitoring; and intercommunication between the pilot, gunner, and ground crews.