Abstract: The data communication device is designed for a towed vehicle having wheels rear lights, brake lights, turn signal lights and an anti-lock braking system, that is drawn by a motor vehicle. This data communication device includes an electrical cable connection (19) for supplying electrical power from the towing vehicle to the rear, brake and turn signal lights; an electrical pulse generator and electrical power supply circuit (14) for producing direct current from wheel motion of the towed vehicle; a rechargeable battery (15) to provide a supplementary direct current in addition to this direct current, when necessary; a controller (10) for the anti-lock braking system including a data producing unit (7) for producing data including mileage covered by the towed vehicle and a wireless transponder (6) operating the gigahertz range for transmission and reception of data from the data producing unit to and from an external data transmitting and receiving station (1).

Abstract: An anti-lock brake control system for trailers is described where the power supply of the parts of the electronic system, which require only a small amount of electric power, is derived from the signals of the one (or several) speed sensor(s) and the power for the amplifier is supplied via the brake light line.