INT 48 - KEYBOARD - CORDLESS KEYBOARD TRANSLATION (PCjr)

	AL = scan code???
Note:	This interrupt may be un-initialized (0000h:0000h) on old machines.
	  This should be checked before calling or hooking this vector.
	MS-DOS/PC DOS 3.3x-4.x KEYB hooked the INT 48h handler. For AL <= 80h
	  it checked that either ALT and neither CTRL key was pressed,
	  and in that case, it cleared the CTRL flag in the BIOS variable at
	  0040:0017h and stored its contents in an internal variable,
	  before continuing with the previous (non-zero) INT 48h handler.
SeeAlso: INT 49"PCjr"