using System.Text;
using System.IO.Ports:
SerialPort sp = new SerialPort();
sp.PortName = "COM2";
sp.Open();
sp.ReadTimeout = 500;
UTF8Encoding utf8 = new UTF8Encoding();
String unicodeString = "\u0001\u00c0\u00c1";
Byte[] encodedBytes = utf8.GetBytes(unicodeString);
foreach (Byte b in encodedBytes) {
   sp.Write(utf8.GetString(encodedBytes));
}
textBox1.Text = sp.ReadLine();