Vehicles such as airliners or trains can be equipped with a form of local area network in which individual network connections are made to individual passenger seats using standard telephony connectors. Passengers having computers can connect to the network using their own conventional telephone cables. Wireless communications technology is used to link the vehicle network to external ground stations or satellite systems. To meet the DC power requirements of mobile computer users, the vehicle includes a DC power source. A normally unused wire-pair in the telephony connectors brings the DC power to each seatback. A slightly modified connector is used to transfer the DC power to the computer's DC power subsystem.