Look on the back of any PC and you'll see a 25-pin RS-232C connector, better known as a parallel port. Theoretically eight times faster than serial ports, parallel ports are also called the printer ports, since that's what you usually find attached to them (although you can get tape backup units, CD-ROM drives, scanners, and other devices in parallel port format these days). Parallel ports come in several configurations. For example, 4-bit ports output 8 bits of data at a time but receive only 4 bits, while 8-bit ports handle 8 bits of data both ways. "Pseudo 8-bit ports" work at similar speeds, but only with more sophisticated software and peripherals.