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 (contrast serial port). 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.