Identification friend or foe



Identification friend or foe, or IFF, is a system used by the UNSC to tag friendly or hostile units for easy identification on a heads-up display or motion tracker. The equipment of a friendly unit generates a signal on a specific frequency, which is interpreted as a "friendly" signal by the receiver. If a signal is not generated, then unit is tagged as a hostile. Friendly units appear as yellow dots on the motion tracker, while the crosshairs of a HUD turn green when pointed at them. Hostile units show up as red on a motion tracker, and the HUD crosshairs turn red.

All UNSC personnel are implanted with a neural interface containing an IFF transponder. Additionally, most UNSC ships, ranging from civilian freighters to UNSC Navy warships, possess IFF transponders displaying their identity, allegiance, and classification.

During the fall of High Charity, John-117 managed to rescue several UNSC Marine prisoners of war. This was due to Cortana identifying their IFF transponders, which were still with the Marines.

List of appearances

 * Halo: Combat Evolved
 * Halo: The Flood
 * Halo 2
 * Halo: Landfall
 * Halo: Combat
 * Halo 3
 * Halo: Contact Harvest
 * Halo 3: ODST
 * Halo: Reach
 * Halo 4
 * Spartan Ops
 * Halo 5: Guardians
 * Halo: Shadow of Intent