public void Start()
{
if (m_port == null) return;
m_port.Open();
m_transmit_thread = new Threading.Thread(new Threading.ThreadStart(mstp_thread));
m_transmit_thread.IsBackground = true;
m_transmit_thread.Name = "MSTP Thread";
m_transmit_thread.Priority = Threading.ThreadPriority.Highest;
m_transmit_thread.Start();
}