Int 66 Fn 43  - Pendos - Pkeyus - ???                                      [n]

   AH = 43h
   BX = ???
   DX = ???

Return: AX = status
       0000h if AH=41h flag set
       else
       AH = ???
       AL = ???
       BX = ???
       DX = ???

See Also: AH=41h