The IFR Aeroflex ATC-1400A is a microprocessor-based test set designed to accomplish complete testing of modern ATC Transponder and DME equipment. When interfaced with the T-1401, I-1402, S-1403DL or SI-1404 accessory units, the ATC-1400A becomes a comprehensive test system for TACAN, Mode 4 IFF transponder and Mode S transponder avionics equipment.