FHandle := CreateFile( pchar(FPortName),
                         GENERIC_READ or GENERIC_WRITE,
                          0 , // Not shared 
                         nil, // No security attributes 
                         OPEN_EXISTING,
                         FILE_ATTRIBUTE_NORMAL,
                          0  // No template 
                        ) ;

  Result := SetCommState( FHandle, dcb );

  Result := SetupComm( FHandle, FInBufSize, FOutBufSize );