INT 14H 02H: Receive a Character

 Expects: AH    02H
          DX    COMM port number (0 to 3)
 Returns: AH    0    = character received successfully
                else = an error occurred; see BIOS COM status codes
          AL    character that came in
    Info: Receives one character from the specified COM port.  If AH is 00
          on return, the received character is in AL.

   Notes: The return status code in AH cannot indicate a time-out error
          since bit 7 is used to flag any error.  Thus, after any error,
          you should use INT 14H 03H to get the full story on what went

See Also: INT 14H: Serial Port I/O
          Asynchronous Adapter Ports
          BIOS Data Area
          ROM-BIOS Functions