IFF Control Box is the front panel of IFF (Identification between Friend and Foe) transponder for pilots. It controls the modes, codes of modes and also performs self-test for respective modes. When the pilot turns on emergency mode then all the modes (M1, M2, M3, MC) turn on and 7700 code sent to the base automatically. In case of OVR, when OVR is “on” then all modes turns off and there will be no reply of M1, M2, M3 and MC from transponder to interrogator (on ground). ID provides the particular identification code to interrogator (on ground) that is assigned to the specific aircraft.