설정:

_relayPort = SerialPort(
      port,
      openNow: false,
      ByteSize: 8,
      Parity: 0,
      StopBits: 0,
      BaudRate: 9600,
      ReadIntervalTimeout: 1,
      ReadTotalTimeoutConstant: 2,
    );

활성화

port.writeBytesFromUint8List(Uint8List.fromList([0x20,0x20,0x0d]));

동작

port.writeBytesFromUint8List(Uint8List.fromList([0x52,0x59,0x20,0x31,0x20,0x31,0x0d]));