The BC-366 Jack Box was part of the RC-36, RC-45, and AN/AIC-2 Interphone Systems, used to control airborne communications of the aircraft interphone and radio during flight and on the ground. The BC-366 Jack Box was commonly used across all US Army Air Force and US Navy multi-crew aircraft, such as the B-17, B-24, B-25, B-26, B-29, C-47, PBY-5A, and others. It was typically positioned at the stations of the pilot, co-pilot, navigator, and radio operator, but may also be at all gunners stations as well depending upon the aircraft. See photo from the 1944 B-17G Flight Manual showing the position of a BC-366 at the pilots side.
Below are the instructions for the BC-366 from the B-24D Flight Manual:
Interphone System Operation—Each jack box has five positions to which the selector switch may be adjusted along with a manual volume control. From these five selector positions the following may be accomplished: (See photo for interphone jack box markings.)
Position 1—"Compass." The audio output of the "Compass Receiver" only will be heard. A limited control of headset volume can be had by manipulation of the volume control. The microphone circuit is inoperative. This position is available at all stations.
Position 2—"Liaison." The liaison receiver output and the side tone of the liaison transmitter will be heard. A limited control of headset volume is possible with operation of the volume control. The microphone, "push-to-talk" switch operates the transmit-receive relay located within the liaison transmitter. The microphone will modulate the liaison transmitter when the microphone switch is closed, and the transmitter is in the "Voice" position. Voice transmission from the "Liaison" position is available only from the Pilot's, Co-Pilot's and Radio Operator's Interphone Stations.
Position 3—"Command." The command receiver output and the side tone from the command transmitter will he heard. A limited control of headset volume can be had by varying the volume control. The microphone "push-to-talk" switch operates the command send - receive relays which are located in the command receiver rack. The microphone will modulate the command transmitter when the "push-to-talk" switch is closed and the transmitter is in the "Voice" position. This position is available at ALL interphone stations.
Position 4—"Inter." Provides an intercommunication system for use between crew members. The microphone connects to the input of the inter-phone amplifier, and the headphones to the output of this amplifier. The volume control is not effective in this position. This position is available at all interphone stations.
Position 5—"Call." This is an emergency call position in which ALL headphones at ALL boxes are in parallel across the output of the interphone amplifier. If an emergency should arise a crew member may contact any interphone station, even though it might be in use, by switching his jack box to the "Call" position. The microphone of the calling station is connected to the input of the interphone amplifier but leaves all other microphones in their respective positions.
This item is New Old Stock, and is in its original packaging measuring 3.5 inches by 5 inches by 3 inches. It is in exceptional condition given its age.