INT 10h,  15h (21)       Return Physical Display Characteristics  Convertible

    Returns the alternate display adapter type and a table describing the
    characteristics of the current display. This service is available only
    for the PC Convertible.

       On entry:      AH         15h

       Returns:       AX         Alternate display adapter type
                                 00h   - No alternate adapter
                                 5140h - LCD
                                 5153h - CGA type display
                                 5151h - Monochrome type display
                      ES:DI      Pointer to 7-word Current display adapter
                                 table (See below)

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       Notes:         The format of the display adapter table is as
                      follows:

                         Word 1 - Display model number
                         Word 2 - Vertical PELs per meter
                         Word 3 - Horizontal PELs per meter
                         Word 4 - Total number of vertical PELs
                         Word 5 - Total number of horizontal PELs
                         Word 6 - Height of PEL in micrometers (vertical
                                  direction)
                         Word 7 - Width of PEL in micrometers  (horizontal
                                  direction)

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                      PC Convertible Display Adapter Tables

          Word     Monochrome    CGA          LCD (CGA)       LCD (Monochrome)
            1        5151h      5153h           5140h               5140h
            2          0        0498h           08E1h                  0
            3          0        0A15h           0987h                  0
            4          0        00C8h           00C8h                  0
            5          0        0280h           0280h                  0
            6          0        0352h           0172h                  0
            7          0        0184h           0172h                  0

    Note that the PC Convertible Technical Reference Manual incorrectly
    documents words 6 and 7 for an LCD acting as a CGA. The correct values
    are listed above.