Each keyboard connects (interfaces)
to the back of the computer with one of three type of
connectors, The most common is the PS/2 style connector
which is used on most new computers. The next most common is one
using a USB connector. Finally, older computers use the AT
style connector. If you have an older computer with the AT style
connector, you can still use a PS/2 connector keyboard if you
attach it using a PS/2-to-AT keyboard adapter