writing tilde (~) character on an AT commands

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C#

ATCommands

GSM

Hi,

I have a project where I need to send an Text Message (SMS) to any mobile number using itegno 3800 GSM modem attached to a USB cable.
I can send SMS for only ordinary message like alphabet and numbers.

my problem is when i used to send a message containing (~) character it doesn't appear on the receiving mobile/device.

here is my code on sending:

port.PortName = p_strPortName;                 //COM1
              port.BaudRate = p_uBaudRate;                   //9600
              port.DataBits = p_uDataBits;                   //8
              port.StopBits = StopBits.One;                  //1
              port.Parity = Parity.None;                     //None
              port.ReadTimeout = p_uReadTimeout;             //300
              port.WriteTimeout = p_uWriteTimeout;           //300
              port.Encoding = Encoding.GetEncoding("iso-8859-1");
              port.Handshake = Handshake.None;
              port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);

              System.Threading.Thread.Sleep(50);

              port.Open();
              port.DtrEnable = true;
              port.RtsEnable = true;

string recievedData = ExecCommand(port, "AT", 300, "No phone connected");
                   recievedData = ExecCommand(port, "AT+CMGF=1", 300, "Failed to set message format.");
                   String command = "AT+CMGS=\"" + PhoneNo + "\"";
                   recievedData = ExecCommand(port, command, 300, "Failed to accept phoneNo");
                   command = Message + char.ConvertFromUtf32(26) + "\r";

                   recievedData = ExecCommand(port, command, 3000, "Failed to send message"); //3 seconds

                   if (recievedData.EndsWith("\r\nOK\r\n"))
                   {
                       isSend = true;
                   }
                   else if (recievedData.Contains("ERROR"))
                   {
                       isSend = false;
                   }

port.DiscardOutBuffer();
               port.DiscardInBuffer();
               receiveNow.Reset();
               port.Write(command + "\r");

               string input = ReadResponse(port, responseTimeout);
               if ((input.Length == 0) || ((!input.EndsWith("\r\n> ")) && (!input.EndsWith("\r\nOK\r\n"))))
               {
                   return input;
               }
               else
               {
                   return input;
               }

please don't mind some missing scripts as I only included some major codes.

my intent is to send SMS completely even it has a special character like (~).

Your feedback and comments are highly appreciated.

Thank you.

Michael John Bernarte