My serial port program code for the usb relay

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Ports;

namespace ConsoleApplication1
{
class Program
{
static SerialPort _serialPort;

static void Main(string[] args)
{

try
{
_serialPort = new SerialPort("COM4");
_serialPort.DtrEnable = true;
_serialPort.Open();

Console.Write(_serialPort.DtrEnable);
Console.Write(_serialPort.BaudRate);
Console.Write(_serialPort.RtsEnable);

DateTime endTime = DateTime.Now.AddSeconds(7);
while (endTime > DateTime.Now)
{
// Process loop
_serialPort.WriteLine("");
}

Console.Write("Port Closing...");
_serialPort.DtrEnable = false;
_serialPort.Close();
}

catch (Exception ex)
{
Console.Write(ex.Message);
}


}


}
}