The following pictures are typical of PC based systems.
The cable provided will connect between these ports.
(Unless you request no cable be sent)
This is the Parallel Port on the printer itself, if you are replacing a printer, and the port on the printer looks like this, it is a Parallel printer.
This is the Parallel Port, located on the back of your computer. If you have one of these available, and your software supports a Parallel port, you may choose to use a Parallel Interfaced receipt printer. Parallel communications are faster and they are typically easier to install and set up