Originally Posted by
Lonewolf_50
Sure they will: it is called a transponder, Mode 3/C.
"IFF" is a term used for transponder. Most mil transponders I worked with had modes I, II, III/C, and IV. The kit someone was painting your with would determine what part of the system responded to you.
Mode III/C interacted with standard air traffic control radar systems. A mil operator can refer to a standard civil transponder's response as an IFF (Mode III/C) reply to his interrogation. The advantage of this is that you only need one piece of kit to send out replies to interrogations via the antenna.