An IFF Display in a Sutherland.
Identification friend or foe (IFF) is a system used primarily by Knightmare Frames and airships. It broadcasts a signal, encoded on a specific channel, that transmits information regarding location, direction and unit type, allowing for tacticians to actively see the battlefield. The system can be a double edged sword, as demonstrated by Lelouch, when the IFF information is used by an enemy in a captured unit. An IFF transponder can be removed, although the exact process is unknown.
In his first battles, Lelouch used the IFF as a means of luring his foes into traps, using them to make it look like his allies were Britannian soldiers in trouble, attracting enemy units that would come to help them to be destroyed. This tactic worked to great effect for Lelouch in the Skirmish in Shinjuku Ghetto. In the Saitama Ghetto Ambush, however, this tactic failed, due to Cornelia's hardened command style, in which she was willing to kill those who disobeyed her orders. At the same time, due to her greater battle experience, Cornelia came to see through this trick quickly.
See Also[]
For the real world see also Identification Friend or Foe.