IBM 770 manual Keyboard ID, System Board

Figure 2-4. Key Numbers for the 85-Key Keyboard

Keyboard ID

The keyboard ID consists of 2 bytes: hex 83AB		(the built-in keyboard
with the external numeric keypad)	or hex 84AB (the built-in keyboard
only). Interrupt 16H, function code	(AH)=0AH, returns	the keyboard
ID.

2-6 System Board