SerialPort mySerialPort = new SerialPort("COM4");
                mySerialPort.BaudRate = 9600;
                mySerialPort.Parity = Parity.None;
                mySerialPort.StopBits = StopBits.One;
                mySerialPort.DataBits = 8;
                mySerialPort.Handshake = Handshake.None;
                mySerialPort.RtsEnable = true;
                mySerialPort.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);

                mySerialPort.Open();

  private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
        {
            Thread.Sleep(2000);
            SerialPort sp = (SerialPort)sender;
            string indata = sp.ReadExisting();