INT 21 U - IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. PC-DOS - KEYBGK - SELECT KEYBOARD LAYOUT
	AX = FAFFh
	CL = keyboard layout
	    31h keyboard 319
	    32h keyboard 220
	BX = code page (869 or 813 decimal)
Return: AL = F1h if installed
	DX destroyed