The Raytheon AN/APX-100 Mark XII/Mode S IFF Transponder was designed to meet the military Global Air Traffic Management (GATM) need for a fully integrated solution.

The Raytheon APX-100 Mark XII/Mode S transponder is based on the U.S. Military standard APX-100 (V), of which more than 15,000 have been fielded on more than 50 different military platforms. This unit integrates the proven Mark XII military design with Mode S Level 3 capability to provide the smallest, integrated military/civil transponder in the world. In addition, this system has been qualified and demonstrated as the data link for Traffic Collision and Avoidance Systems (TCAS), and Enhanced TCAS (ETCAS) to meet flight safety mandates without compromising mission critical identification. The system has been designed with growth potential for future requirements such as Change 7 and Automatic Dependent Surveillance (ADS-B), Airborne Data Link Processor (ADLP).