Int 11 Fn 79  - Rainbowfax V1.3 - Sfengine Api - ???                       [F]

   AH = 79h
   AL = subfunction
       01h set ??? flag

       Return: AX = previous state (0000h already set, 0001h clear)
       02h clear ??? flag (refer to subfunc 01h)

       Return: AX = 0001h
       03h set ??? flag (different from subfn 02h or 04h)

       Return: AX = 0001h
       04h clear ??? flag (different from subfn 02h or 03h)

       Return: AX = 0001h
       else

       Return: AX = FFFFh (invalid subfunction)

See Also: AH=77h,AH=78h,AH=7Ah,AH=7Ch