using (System.IO.StreamWriter file =
                    new System.IO.StreamWriter(@"/home/pi/Tosend.txt"))
                {

                    foreach (byte line in Start2)
                    {
                        file.Write(line.ToString("X"));
                    }

                    foreach (byte line in MSG2)
                    {
                        file.Write(line.ToString("X"));
                    }


                    foreach (byte line in END2)
                    {
                        file.Write(line.ToString("X"));
                    }


                }

23033313933330

031930

printf "x2x30....x30" > "test1.txt"