PC Interfaces 101


Two PS/2 ports: one color-coded, the other color neutral

Named for the old IBM PS/2, these connectors have been widely used as the standard interfaces for keyboards and mice, but are slowly giving way to USB. The following color coding schemes for connectors are widely used:

  • Violet: keyboard*
  • Green: mouse

It's also quite common to see such connectors in a neutral gray color on both mouse and keyboard. Switching the mouse and keyboard connections on the motherboard port block is possible, but is harmless. If you do this you will quickly know it, because if these connections are switched neither mouse nor keyboard will work. Many PCs won't even boot if keyboard and mouse are inadvertently switched. The fix is quick and easy: switch the two connectors around the right way, and everything should work!

USB PS/2 Adapter

Uwe Scheffel