The radar identification system is composed of a receiver-transmitter, a transponder control panel, a transponder in flight test set, an antenna and a crypto-secure MODE 4 computer transponder.

The receiver-transmitter provides IFF identification in response to coded interrogations from ground, shipborne or airborne radar stations. In addition the signal returned from the IFF receiver transmitter can be used by the interrogating station to determine range and azimuth information as well.

The receiver-transmitter operates in MODES 1, 2, 3/A and C. With the M-C switch in the ON position it provides automatic reporting of pressure altitude to ground stations. This information is provided by the co-pilot’s barometric altimeter encoder.

The KIT-1C/TSEC computer operates in conjunction with the radar identification equipment to accept and process MODE 4 (encrypted) interrogation signals and generate appropriate MODE 4 replies. Valid MODE 4 interrogation signals may be monitored through the interphone radio control system and an indication that appropriate MODE 4 replies are being generated and transmitted is provided by a REPLY light on the transponder control panel. Fault conditions which may arise within the computer and affect the transmission of MODE 4 replies will cause IFF lamp on the caution panel to illuminate and an audio tone will be heard in the operator’s head-set.

Electrical power of 115 VAC is supplied from the No.1 generator through a circuit-breaker marked “IFF ØC” on the AC portion of the radio circuit-breaker panel. The 28 VDC power is supplied from the No.1 radio bus through two circuit-breakers marked “IFF” on the DC portion of the radio circuit-breaker panel.