The PS/2 port is a 6-pin Female Mini-DIN connector, named after the IBM PS/2 (Personal System/2) computers that first featured it.
There are 3 different versions of the port found on ThinkPads and the Docks and Port Replicators:
- PS/2 Mouse
- PS/2 Keyboard
- PS/2 Mouse with PS/2 Keyboard (requires a PS/2 splitter cable for the keyboard)
Older ThinkPads typically feature the combined PS/2 port, meaning you need the special PS/2 splitter cable to directly attach a PS/2 Keyboard.
On Docks and Port replicators you can either find the combined port, or two individual ports for Keyboard and Mouse.
Current ThinkPads no longer have a physical PS/2 port, but still have the logic integrated, all that is required is to attach the ThinkPad to a supported Dock or Port Replicator with a PS/2 port.