Int 10h, 1A00h          Get Display Combination Code                MCGA, VGA

    Returns the type of display connected to the computer.

        Entry   AX = 1A00h

        Return  AL = 1Ah   If function supported
                BL = Active display code
                BH = Inactive display code
                     (zero on single-display systems)


             Display
               Code     Meaning
                00h     No display
                01h     MDA with monochrome display
                02h     CGA with color display
                03h     Reserved
                04h     EGA with color display
                05h     EGA with monochrome display
                06h     Professional Graphics Controller
                07h     VGA with analog monochrome display
                08h     VGA with analog color display
                09h     Reserved
                0Ah     MCGA with digital color display
                0Bh     MCGA with analog monochrome display
                0Ch     MCGA with analog color display
                FFh     Unknown display type