Devices such as Printers, Parallel-scanners, and external Zip drives are connected to the plugs on the back of the cards. The newer type of parallel ports follow the IEEE1284 standard which allows for faster speeds and gives devices a path to communicate with the host as well as much larger cable distances. Your printer or parallel device will determine which type of cable you will need. It is not enough to just buy a IEEE-1284 cable and expect the device to operate using that mode.
Most computers have a parallel port on the motherboard, and a few have an add-on parallel card.
When installing parallel cards you must be careful. They are usually referred to as LPT port settings. On the negative side, most computers have so many components installed that there might not be an IRQ line available to use, so you have to check in advance to see what IRQ lines are used before deciding to add a second printer port. Also a unique address must be set for each port. An alternative to using a second parallel port is installing a switch box.