Int 2F/AX=C0AEh

AX = C0AEh

Return:
AX = 4453h if installed
CX = 5259h if installed
Range:
AH=C0h to AH=FFh, selected by scanning for signature

See Also: AX=C000h"HP 100LX" - AX=C001h"HP 100LX" - AX=C0AFh"HP 100LX"