title: SmsSubmitPdu GSMComm command is not supported by the device Wavecom modem
body: <p>i am using GSMComm library and Wavecom modem to create simple program SMS Sender, when i press the button Send in my winform a got a message debug in my VS2010.</p>
  
  <p><strong><em>The phone reports an unspecified error. This typically happens when a command is not supported by the device, a command is not valid for the current state or if a parameter is incorrect.</em></strong></p>
  
  <p>this my code </p>
  
  <pre><code>private void btnSend_Click(object sender, EventArgs e)
          {
              var port = "COM3"; // default port to connect modem wavecom
              var baudRate = 115200;
              var timeout = 300;
              var comm = new GsmCommMain(port, baudRate, timeout);
  
          try
          {
              var msg = txtIsiPesan.Text;
              var phoneNumber = txtNoTujuan.Text;
              comm.Open();
              SmsSubmitPdu pdu = new SmsSubmitPdu(msg, phoneNumber, "");
              comm.SendMessage(pdu); //debug found error here
              comm.Close();
          }
          catch (Exception ex)
          {
              MessageBox.Show(ex.Message, "error");
          }
  
      }
  </code></pre>
  
  <p>Is this indicate that my wavecom modem didn't support to SmsSubmitPdu ?
  Please suggest me thanks.</p>