Access a COM Port in C#

Use the System.IO.Ports.SerialPort class. This class represents a serial port resource and defines
methods that enable communication through it.

Example source code

using System;
using System.IO.Ports;
namespace biz.hotdir
{
static class COmDemo
{
static void Main(string[] args)
{
using (SerialPort port = new SerialPort("COM1"))
{
// Set the properties.
port.BaudRate = 9600;
port.Parity = Parity.None;
port.ReadTimeout = 5;
port.StopBits = StopBits.One;
// Write a message into the port.
port.Open();
port.Write("Hello world!");
Console.WriteLine("Wrote to the port.");
}
// Wait to continue.
Console.WriteLine(Environment.NewLine);
Console.WriteLine("Main method complete. Press Enter.");
Console.ReadLine();
}
}
}