A standard parallel port (SPP) is a port for connecting various relatively high bandwidth peripherals, most commonly printers, to a PC. Later versions of the SPP allow duplex communication. They use the DB-25 connector. The original SPP, by Centronics, was introduced in 1970 and soon became the de facto industry standard. However, a number of different manufacturers used the SPP with a variety of connectors, such as the DC-35, the DD50 and the M50.