Parallel port

In computing, a parallel port is an interface from a computer system where data is transferred in or out in parallel, that is, on more than one wire. A parallel port carries one bit on each wire thus multiplying the transfer rate obtainable over a single cable. There will usually be some control signals on the port as well to say when data is ready to be sent or received.

It is mostly used by a microprocessor to communicate with peripherals. The commonest kind of parallel port is a printer port, e.g. a Centronics port which transfers eight bits at a time. Disks are also connected via special parallel ports, e.g. SCSI or ATA.

The examples of parallel ports:

• 8255[?] for Intel microprocessors
• Z80PIO[?] for Zilog microprocessors

See also serial port.

Parts of this article were originally based on material from FOLDOC, used with permission. Update as needed.