Serial port send receive

if (words[2].Equals("00"))
            {
                panel3.BackColor = Color.Green;
            }
            else
            {
                panel3.BackColor = Color.Red;
            }

<pre>public partial class Form1 : Form
    {
        Communication comm;
        Int32 count = 0;


        public Form1()
        {
            InitializeComponent();
            comm = Communication.Instance();
            comm.Communication_Set(9600, 8);
            comboBox1.Items.Clear();
            this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(this.Form_Closing);
            foreach (string selCOM in comm.selectCOM())
            {
                comboBox1.Items.Add(selCOM);
            }
            comboBox1.Sorted = true;
            label1.Text = "";
        }

        private void openCOM_Click(object sender, EventArgs e)
        {
            try
            {
                label1.Text = comm.openCOM(comboBox1.Items[comboBox1.SelectedIndex].ToString());
            }

            catch
            {
                label1.Text = "First select COM port!";
            }
        }

        private void closeCOM_Click(object sender, EventArgs e)
        {
            label1.Text = comm.CloseCOM();
        }

        private void sendData_Click(object sender, EventArgs e)
        {
            if (textBox1.Text != string.Empty)
            {
                string hexString = textBox1.Text;
                byte[] rxByte = new byte[1];



                if (!comm.serialWrite(stringToHEX(hexString), 0, stringToHEX(hexString).Length)) 
                { 
                    label1.Text = "Cannot send data!Try to open COM port first!"; 
                    return; 
                }
                Thread.Sleep(50);
                //textBox2.Text += count.ToString() + "";
                while (comm.serialBytesToRead() > 0)
                {
                    rxByte[0] = comm.serialRead();
                    textBox2.Text += ByteToHex(rxByte).ToString();
                }
                //textBox2.Text += " \r\n";
            }
        }


        private void Clear_Click(object sender, EventArgs e)
        {
            textBox2.Text = string.Empty;
        }


        private string ByteToHex(byte[] data)
        {
            StringBuilder sb = new StringBuilder(data.Length * 3);
            foreach (byte b in data)
                sb.Append(Convert.ToString(b, 16).PadRight(3, ' ')); // edw
            return sb.ToString().ToUpper();
        }
        public byte[] stringToHEX(string s)
        {
            char[] splitter = {};
            string[] splitS = s.Split(splitter, StringSplitOptions.RemoveEmptyEntries);

            byte[] buff = new byte[splitS.Length];

            for (int i = 0; i < splitS.Length; i++)
            {
                try
                {
                    buff[i] = Convert.ToByte(splitS[i], 16);
                }

                catch
                {
                    //buff[i] = 0x00;
                }
            }
            return buff;
        }


        private void Form_Closing(object sender, FormClosingEventArgs e)
        {

            if (comm.serialIsOpen()) comm.CloseCOM();

        }

        private void textBox2_TextChanged(object sender, EventArgs e)
        {
            string data = textBox2.Text;
            string[] words = data.Split(' ');

            if (words[0].Equals("FF"))
            {
                panel1.BackColor = Color.Green;
            }
            else
            {
                panel1.BackColor = Color.Red;
            }
            if (words[1].Equals("A1"))
            {
                panel2.BackColor = Color.Green;
            }
            else
            {
                panel2.BackColor = Color.Red;
            }
            if (words[2].Equals("00"))
            {
                panel3.BackColor = Color.Green;
            }
            else
            {
                panel3.BackColor = Color.Red;
            }

        }
        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            sendData.PerformClick();

        }

        private void timer2_Tick(object sender, EventArgs e)
        {
            Clear.PerformClick();
        }