Also capable of carrying out the transponder functions needed for civilian Air Traffic Control, the most widely used military identification friend or foe (IFF) transponder is the AN/APX-100.  It is a small unit, which can be mounted:
- in or beside the main control panel
- with APX-100 specific cabling from a small remote control unit to the main transponder
- on a MIL-STD-1553 bus with control from a bus-attached computer.
Aircraft on which it is deployed include the F-18 Hornet, P-3 Orion, F-18 Super Hornet, E-2C Hawkeye 2000, H-60 helicopters, LCAC, OH-58 Kiowa Warrior, AH-1 Cobra, MH-53 Pave Low, CH-47 Chinook, C-130 Hercules, C-5 Galaxy, C-17 Globemaster III, C-141, C-21, MiG fighters, AH-64 Apache and Mil helicopters, as well as several Unmanned Aerial Vehicles (UAVs), such as MQ-5 Hunter, MQ-1 Predator and MQ-4 Global Hawk.
- Raytheon, Mark XII/Mode S IFF Transponder, AN/APX-100