INT 16 - K3PLUS v6.00+ (API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. v2.00+) - SET OPTIONS
	AX = AF51h
	BX = 4B33h ('K3')
	CX = switches
Return: AL = status
	    00h done
		CX = previous switch settings
	    01h switch not supported
	    FFh other error
SeeAlso: AX=AF4Dh,AX=AF50h,AX=AF80h