The AN/AIC-7 is designed to provide simplified control over all radio receivers and transmitters aboard the aircraft and with both head phone and loudspeaker type interphone systems arranged to permit maximum flexibility of communication facilities within the weight and size limits imposed by overall aircraft requirements. The pilot, copilot, radio operator and navigator are each provided with a master control unit which permits selecting any one or combination of eight radio receiver outputs as desired. transmission aver any one of three radio transmitters, and interphone communication over headphones or loudspeakers to all crew members aboard. The pilot may also connect either one or both of two radio receiver outputs to the loudspeaker system for mounting i n s i d e t h e aircraft and may call external to the aircraft over an outer loud-speaker unit. Members of the crew other than the pilot. copilot, radio operator and navigator are each provided with a simplified control unit (referred to throughout this section as a statlon box) which permits reception from the VHF radio receirer, transmission over the VH? transmitter under control of one of the master control units, and interphone communication over headphones or loudspeakers to other members of the crew. Any one or more station boxes mag be arranged to permit calls external to the aircraft over an outer ioud-speaker unit..