Function 01h (1)         Read Keyboard Character and Echo

    Reads a character from the standard input device (usually the
    keyboard), and echoes it to the standard output device (usually the
    screen).

       On entry:      AH         01h

       Returns:       AL         Character read

  ──────────────────────────────────────────────────────────────────────────

       Extended ASCII For the special keys, such as the cursor and
                      function keys, this function returns a 0 in AL; call
                      the function again to read the extended code of the
                      special character. (See the Key codes for a listing
                      of the extended codes.)

       Ctrl-Break &   DOS generates an INT 23h.
       Ctrl-C

       Note:          This function checks for Ctrl-Break and Ctrl-C. Use
                      Function 07h if you don't wish to check Ctrl-Break
                      and Ctrl-C.