INT 16H: Keyboard Services

 This is the application-level interface to the keyboard.  Keystrokes are
 processed asynchronously (in the background).  As each keystroke is
 received from the keyboard, it is processed by INT 09H and placed into a
 circular queue at 40:001e in the BIOS Data Area.

          AH  BIOS Service                      Supported by
          ▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀
          00H read keyboard input                [PC] [XT] [AT]
          01H query keyboard status/preview key  [PC] [XT] [AT]
          02H query keyboard shift flags         [PC] [XT] [AT]
          03H set typeamatic rate and delay      [PC] [XT] [AT]
          04H (reserved)
          05H store key data                               [AT]

          10H read extended keyboard input                 [AT]
          11H query extended keyboard status               [AT]
          12H query extended keyboard shift flags          [AT]

See Also: ROM-BIOS Functions
          Character I/O Functions (DOS fns)
          BIOS Data Area
          Cables and Pin Outs