USAAF throatmicrophone extension cord with British plug

USAAF throatmicrophone extension cord with British plug, this was found with a British 1941 pattern Mae West. When early microphones had built-in press-to-talk switches, operation was simple. But with the introduction of throat mics, oxygen-mask mics, and integrated headsets like the H-46/UR, a separate method was needed to key the transmitter. This led to various external switches, often specific to certain aircraft. Early systems placed the switch on the cable leading to the interphone jack box; it clipped to the flight suit with a lanyard and was used to operate the interphone or key the HF/VHF transmitter.