When IBM introduced the PC, in 1981, the parallel printer port was included as an alternative to the slower serial port as a means for driving the latest high performance dot matrix printers. The parallel port had the capability to transfer 8 bits of data at time whereas the serial port transmitted one bit at a time. When the PC was introduced, dot matrix printers were the main peripheral that used the parallel port. As technology progressed and the need for greater external connectivity increased, the parallel port became the means by which you could connect higher performance peripherals. These peripherals now range from printer sharing devices, portable disk drives and tape backup to local area network adapters and CD ROM players. The problems faced by developers and customers of these peripherals fall into three categories. First, although the performance of the PC has increased dramatically, there has been virtually no change in the parallel port performance or architecture. The maximum data transfer rate achievable with this architecture is around 150 kilobytes per second and is extremely software intensive. Second, there is no standard for the electrical interface. This causes many problems when attempting to guarantee operation across various platforms. Finally, the lack of design standards forced a distance limitation of only 6 feet for external cables.

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