A standard interface for data terminal equipment (DTE) first published by the Electronics Industry Alliance (EIA) in the early 1960s and originally known as RS-232 (Recommended Standard 232), EIA-232 addresses signal voltages, signal timing, signal function, a protocol for information exchange, and either 25-pin or 9-pin mechanical connectors. Most personal computers have an RS-232 serial port for connecting external modems, printers, scanners, and other peripheral devices. See also 1394, EIA, modem, protocol, short haul modem, USB, and voltage.