An RKE system consists of an RF transmitter in the keyfob (or key) that sends a short burst of digital data to a
receiver in the vehicle, where it is decoded and made to open or close the vehicle doors or the trunk via receivercontrolled
actuators. The wireless carrier frequency, is currently 315MHz in the US/Japan and 433.92MHz (ISM
band) in Europe. In Japan the modulation is frequency-shift keying (FSK), but in most other parts of the world,
amplitude-shift keying, or ASK is used. The carrier is amplitude modulated between two levels: To save power,
the lower level is usually near zero, producing complete on-off keying (OOK).