Abstract: A sensor circuit detects whether an electrical connection exists between a tractor portion and a trailer portion of a tractor/trailer vehicle. The circuit includes a first chassis electrical ground in the tractor portion and a second vehicle chassis ground in the trailer portion. A first electrical conductor, such as a wire in an umbilical cable, is coupled to the first chassis electrical ground, preferably through a tractor appliance circuit, such as a turn indicator light circuit in the tractor portion. A second electrical conductor, such as a contact in a connector on the trailer portion which mates with the umbilical cable, is operable to electrically connect to and disconnect from the first electrical conductor. The circuit includes a detection circuit for providing an indication signal based upon whether an electrical connection exists between the first electrical conductor and the second electrical conductor.

Abstract: A system and method for sending e-mail messages between an authorized user connected to a publicly accessible computer network system and a vehicle occupant using a private communication system having different messaging formats. E-mail messages are received by an interface, converted into an appropriate format, and transmitted to an intended user or vehicle occupant if a sufficient balance exists in an account associated with the vehicle occupant.

Abstract: A communication system for transmitting messages includes a mobile private communication system. The mobile private communication system has a mobile terminal disposed in each of a plurality of trucks, the mobile terminal having a transceiver, an electronic control unit in communication with the transceiver, and a display in communication with the electronic control unit for displaying the messages. A satellite transmits the messages to the mobile terminal, and a satellite dish transmits the messages to the satellite. A satellite hub converts the messages to a satellite transmittable form. An interface is provided, having a local management system for adjusting an account for each of the messages being transmitted to the mobile terminal, and further for ensuring that the account has a sufficient balance prior to transmitting messages to the mobile terminal.