Automotive Transponders find use in applications where contactless identification is in demand. Transponder exchanges data by an inductive coupling with a receiver base station. It is also used in auto locking applications. This involves placing a microchip in the head of the key, which are a miniature transmitter and receiver. There is an engine management system in the engine compartment that can recognize the signals transmitted from the key. If the correct signals are not detected the engine will not start.