How to Send SMS using GSM Modem in C#

This article explains in the simple way to send the SMS using GSM Modem in C#.

1.  First, connect the GSM Modem and find the COM port. To do this

• Click on the Start button in the bottom left corner of your Screen. (shortcut Win+R)
• Then type "devmgmt.msc", and hit Enter.
• If Windows asks for your permission to continue, click on Continue.
• When the device manager shows up, Find the entry that says "Ports (COM & LPT)" and click on the (+) beside it to expand it.
• The COM port number is shown in parentheses beside the name.

 2.  Create a new Windows forms application and add three textboxes for Mobile number(txtmobile),Port number(txtport) and message(txtmessage).

3.  Add the following namespace.

  using System.IO.Ports;

 4.  Then add a button control(butSend) to your form and write the code in the button_click event.

          SerialPort serialport = new SerialPort();

           try

           {

               int mSpeed = 1;

               serialport.PortName = txtport.Text;

               serialport.BaudRate = 96000;

               serialport.Parity = Parity.None;

               serialport.DataBits = 8;

               serialport.StopBits = StopBits.One;

               serialport.Handshake = Handshake.XOnXOff;

               serialport.DtrEnable = true;

               serialport.RtsEnable = true;

               serialport.NewLine = Environment.NewLine;

             try

                    {

                        serialport.Open();

                    }

                    catch (Exception)

                    {

               MessageBox.Show("Try another Port."+ Environment.NewLine +"Phone not detected or The requested resource is in use.","CONNECTION ERROR",   MessageBoxButtons.OK,MessageBoxIcon.Error);

                     return;

                    }

               serialport.WriteLine("AT+CMGF=1" + Environment.NewLine);

               System.Threading.Thread.Sleep(200);

               serialport.WriteLine("AT+CSCS=GSM" + Environment.NewLine);

               System.Threading.Thread.Sleep(200);

               serialport.WriteLine("AT+CMGS=" + (char)34 + txtmobile.Text

               + (char)34 + Environment.NewLine);

               System.Threading.Thread.Sleep(200);

               serialport.WriteLine(txtmessage. Text + (char)26);

               System.Threading.Thread.Sleep(mSpeed);

               serialport.Close();

           }

           catch (Exception)

           {

               if (serialport.IsOpen)

               serialport.Close(); 

            MessageBox.Show("Couldn't send the SMS.","CONNECTION ERROR",MessageBoxButtons.OK,MessageBoxIcon.Error);

           }

 5.  Run the program
      Enter the Mobile number,COM Port and message and click on send buton to send the SMS.

Some useful articles:
1. http://codeglobe.blogspot.co.uk/2009/02/sending-sms-in-cnet-using-gsm-modem-and.html
2. http://www.codeproject.com/Articles/20420/How-To-Send-and-Receive-SMS-using-GSM-Modem