Abstract: Power supplies which include sockets for supplying DC voltages as well as cables for supplying DC voltages to internal components of, for example, a computer are configured to prevent a user from connecting to an inappropriate DC voltage. The apparatus includes a special multiple din socket which provides a different voltage at each din of a subset of the dins, only one din of which is alive at a time. The apparatus includes a switch at each socket operative to select only a single din of a subset of dins at that socket. The illustrative apparatus includes several sockets, each one of which includes a different subset of dins selected by a switch, a single din at a time.

Abstract: Electrical equipment such as a personal computer includes a plurality of internal components which require different voltages including low voltages of about five volts for operation. The different voltages are supplied by an internal power supply, with a voltage regulator, which is itself connected to an appropriately transformed high voltage supply typically from an in-the-wall source. Peripherals such as a FAX/modem, CD ROM, or tape recorder are powered by special connectors in the face of the computer housing and connected to the appropriate outputs of the internal power supply to obtain low voltage power directly from the host computer in the absence of a transformed connection to a house supply.