Identification, friend or foe (IFF) is an identification system designed for command and control. It enables military and civilian interrogation systems to identify aircraft, vehicles, or forces as friendly and to determine their bearing and range from the interrogator. IFF was first developed during World War II. The term is a misnomer, as IFF can only positively identify friendly targets but not hostile ones. If an IFF interrogation receives no reply or an invalid reply, the object cannot be identified as friendly but is not positively identified as a foe. There are many reasons that friendly aircraft may not properly reply to IFF.