Int 42 Fn 7503  - Toshiba Laptops - Get Display Status                     [V]

   AX = 7503h

Return: AX = 7575h if supported
   CX = 0001h if supported
   BH = display type (00h color, 03h monochrome)
   BL = display state
       01h internal LCD display is active
       02h external VGA display is active
       03h both displays active / DeskStation display mode enabled
       (not possible on all machines)

Note:  used by VCHAD.EXE and supported by all Toshiba VGA laptops until about
     1994 (string "TOSHIBA " at F000:E010h should be checked before call)
   no longer supported by T21xx series, use INT 10/AX=5F50h instead
   INT 42 normally points to F000:F065h but may be redirected by QEMM386

See Also: AX=7500h,AX=7504h,INT 10/AX=5F50h,INT 15/AH=C0h