AirWire is a popular wireless control system for large scale model railroad locomotives and accessories. A handheld transmitter is used to control train speed, lights, sound, and trackside accessories. Analysis of this system revealed that the protocol is based on the DCC (Digital Command Control) standard used for powering and controlling trains through conductive track, but instead transmitted over 900-MHz ISM band channels as a continuous FSK stream. Transmitters and receivers both use the …