Texas Instruments 5000 - Manual (Page 275)

Call with:
AH = FAh
AL = 03h
BH = Request Parameter
00h = Reverse
01h = Expanded Mode
02h = Block Cursor
03h = Display
04h = Monitor Type
05h = LCD Power
06h = Backlight
07h = Text Resolution
08h = Contrast Enhancement
09h = LCD Palette
0Ah = External VGA
FFh = Return zero based max request number
Returns:
AH = Error Code
00h = No Error
86h = Invalid Parameter
BL = Video Parameter
F-10 Added Interrupt 15 Functions