Editing IBM Personal Computer keyboard (section)

==Types==
The earliest of IBM Personal Computer keyboards were slightly different than the more common version of the keyboard.  In fact, the IBM PC XT Technical Reference manual published in 1983 lists two different types of IBM Personal Computer keyboards identified as '''Type 1''' and '''Type 2'''.  The one most commonly found is the Type 2 keyboard because it was manufactured early in the product life cycle for the IBM Model 5150 PC and used throughout including the product life cycle for the IBM Model 5160 PC XT.  

The '''Type 1''' keyboard is constructed with different internal electronics; including an extra activated pin for RESET in the normal 5 pin DIN cable.  The '''Type 2''' keyboard has that pin but it is not internally connected so the later keyboard performs a keyboard reset internally when powered on. While there is this difference, both use IBM’s '''XT''' protocol for communication.

While the '''Type 1''' keyboard appears to always have a metal keyboard connector that mates with the IBM PC, not all IBM Personal Computer keyboards with a metal connector are '''Type 1'''.  The only true way of determining if an IBM Personal Computer keyboard is '''Type 1''' is by opening it and checking for the elongated internal PCB with the extra electronics.