Int 2F Fn D200  - Quarterdeck Rpci - Installation Check                    [Q]

   AX = D200h
   BX = 5144h ("QD")
   CX = 4D45h ("ME")
   DX = 4D30h ("M0")

Return: AL = FFh installed
   if BX,CX,DX registers were as specified on entry:
       BX = 4D45h ("ME")
       CX = 4D44h ("MD")
       DX = 5652h ("VR")

Notes: AH=D2h is the default multiplex number for the Quarterdeck RPCI
     (Resident Program Communication Interface), but it may use the first
     available multiplex number in the range D2h through FFh, then C0h
     through D1h
   the RPCI is supported by QEMM v5.0+, QRAM, MANIFEST, VIDRAM, etc.
   for AL <> 0, if the BX/CX/DX values don't match the identifier of a
     Quarterdeck product, it just chains to the previous INT 2F handler

See Also: AX=D201h/BX=4849h,AX=D201h/BX=4D41h,AX=D201h/BX=4D45h

See Also: AX=D201h/BX=5145h,AX=D201h/BX=5649h