INT 2F - Quarterdeck RPCI - INSTALLATION CHECK
        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
SeeAlso: AX=D201h/BX=4849h,AX=D201h/BX=4D41h,AX=D201h/BX=4D45h
SeeAlso: AX=D201h/BX=5145h,AX=D201h/BX=5649h

.