PS/2 port connections are extremely rare today, but when they are used, they are generally used for a barcode scanner in what is called a "keyboard wedge" interface. This simply means the barcode scanner's cable has a Y split at the end and a PS/2 keyboard is connected to one end and the other end is connected to the POS computer. This allows (wedges) both the barcode scanner and keyboard to use the same PS/2 port. Many computers today no longer have a PS/2 port.
Please see our interface type buying guide if you are unsure over what interface type you need for your barcode scanner. And if you are still unsure, simply give us a call. It would be great to hear from you.