PS/2 Connector

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Before you start

Objectives: learn what are PS/2 ports, how do they look like and why do we use them.

Prerequisites: no prerequisites.

Key terms: mini, din, port, connect, keyboard, mouse, pc, purple, green, case, key, usb


Mini-DIN

Mini-DIN connector is also called a PS/2 connector because in 1994 IBM came out with a line of computers called PS/2, which introduced a small, fixed-pin adapter for both mice and keyboards. It is a round plug with 6 pins in it. It also has a little key that keeps us from plugging it in upside down. The connector’s sleeve has a notch to ensure proper alignment when inserted into the port and to prevent the pins in the connector from being bent.

 ps/2 connector

Image 317.1 – PS/2 Connectors

The mini DIN is a new version of the older DIN connector. It was used to connect the keyboard with the PC before the PS/2 connector emerged.

5 pin din

Image 317.2 – 5 Pin DIN Connector

On the computer, mini-DIN ports are two small circles positioned on the back of the computer case. Both the keyboard and the mouse use the PS/2 connector, so it’s important to connect the correct device to the corresponding port. In the old days they were black, and they were identical. Sometimes they didn’t have any markings on them so there was not way to tell which was which, but by default we used the lower one for the keyboard and the upper one for the mouse (when we put our computer case on the side where the motherboard is). Over the years we started to use color standardization (PC99 standard). With this standard we use purple mini-DIN port to connect the keyboard and green mini-DIN port to connect the mouse. An older color scheme used orange for the keyboard and purple for the mouse, but we won’t see it any more.

 Mini-DIN Ports

Image 317.3 – Mini-DIN Ports

On some motherboards we can find only one mini-DIN port which we can use to connect the keyboard or the mouse. That single mini-DIN is usually colored half purple and half green. PS2, parallel and serial ports are being replaced by USB.

Remember

Mini-DIN connector is also called a PS/2 connector. With PC99 standard we use purple mini-DIN port to connect the keyboard and green mini-DIN port to connect the mouse. PS2, parallel and serial ports are being replaced by USB.