In computing, a parallel port is a type of physical interface used in conjunction with a cable to connect separate peripherals in a computer system. Over a parallel port, binary information is transferred in parallel: each bit in a particular value is sent simultaneously as an electrical pulse across a separate wire (see parallel communications), in contrast to a serial port, which requires each bit to be sent in series over a single wire. The number of wires and the type of connector on a parallel port can vary.

Although there are many types of parallel interfaces, the unqualified term "parallel port" usually refers to a more or less IEEE 1284 compliant interface, also known as a "Centronics-style" interface.



For the most part, the USB interface has replaced the Centronics-style parallel port — as of 2006, most modern printers are connected through a USB connection, and often don't even have a parallel port connection. On many modern computers, the parallel port is omitted for cost savings, and is considered to be a legacy port.