AT commands Send/receive SMS

Question

I am new to AT commands. I am using Nokia E71 to send and receive SMS. I am designing an application for sending SMS, but my code is not working.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO.Ports;
using System.Threading;

namespace AT_commands
    {
    public partial class Form1 : Form
        {
        SerialPort serialPort;
        public Form1()
            {
            InitializeComponent();
            }

        public void Form1_Load(object sender, EventArgs e)
            {
            this.serialPort = new SerialPort();
            this.serialPort.PortName = "COM23";
            this.serialPort.BaudRate = 9600;
            this.serialPort.Parity = Parity.None;
            this.serialPort.DataBits = 8;
            this.serialPort.StopBits = StopBits.One;
            this.serialPort.Handshake = Handshake.RequestToSend;
            this.serialPort.DtrEnable = true;
            this.serialPort.RtsEnable = true;
            this.serialPort.NewLine = System.Environment.NewLine;
            send_sms();
            }
        public bool send_sms()
            {
            label1.Text = "Loaded Successfuly";
            String SMSMessage = "Message to send";
            String CellNumber = "+923333333333";
            String messageToSend = null;
            if (SMSMessage.Length <= 160)
                {
                messageToSend = SMSMessage;
                }
            else
                {
                messageToSend = SMSMessage.Substring(0, 160);
                }
            if (this.IsOpen == true)
                {
                this.serialPort.WriteLine(@"AT" + (char)(13));
                Thread.Sleep(200);
                this.serialPort.WriteLine("AT+CMGF=1" + (char)(13));
                Thread.Sleep(200);
                this.serialPort.WriteLine(@"AT+CMGS=""" + CellNumber + @"""" + (char)(13));
                Thread.Sleep(200);
                this.serialPort.WriteLine(SMSMessage + (char)(26));
                return true;
                }
            return false;
            }
        public void Open()
            {
            if (this.IsOpen == false)
                {
                this.serialPort.Open();
                }
            }

        public void Close()
            {
            if (this.IsOpen == true)
                {
                this.serialPort.Close();
                }
            }

        public bool IsOpen
            {
            get
                {
                return this.serialPort.IsOpen;
                }
            }

        public void Dispose()
            {
            if (this.IsOpen)
                this.Close();
            }
        }
    }

Please help me with this code!

Need some more information than that. Is there an error message? Did you step through the code? What have you tried to do to debug? — Steve Czetty, Sep 05 '12 at 22:41
Actually, if u help me in reading SMS from mobile, there was a problem in code. But now my application is sending messages, please help me in reading SMS from mobile — Ahmed Khakwani, Sep 05 '12 at 22:52

score 7 · Answer 1 · answered Mar 04 '13 at 09:25

Here's my code

using System;
using System.IO.Ports;
using System.Threading;
using System.Windows.Forms;

namespace CSharp_SMS
{
  public partial class Form_SMS_Sender : Form
  {
    private SerialPort _serialPort;
    public Form_SMS_Sender()
    {
        InitializeComponent();
    }

    private void buttonSend_Click(object sender, EventArgs e)
    {
        string number = textBoxNumber.Text;
        string message = textBoxMessage.Text;

        //Replace "COM7"withcorresponding port name
        _serialPort = new SerialPort("COM7", 115200);   

        Thread.Sleep(1000);

        _serialPort.Open();

        Thread.Sleep(1000);

        _serialPort.Write("AT+CMGF=1\r");

        Thread.Sleep(1000);

        _serialPort.Write("AT+CMGS=\"" + number + "\"\r\n");

        Thread.Sleep(1000);

        _serialPort.Write(message + "\x1A");

        Thread.Sleep(1000);

        labelStatus.Text = "Status: Message sent";

        _serialPort.Close();
        }
    }
}

Here's a link http://circuitfreak.blogspot.com/2013/03/c-programming-sending-sms-using-at.html

score 2 · Answer 2 · answered Sep 12 '12 at 11:45

Why dont you open the port connection in the form_load() itself, later you can close it at the end as you did.

And do these too in Form_Load():

string cmd = "AT";
port.WriteLine(cmd + "\r");
port.Write(cmd + "\r");
port.WriteLine("AT+CMGF=1");

And simplifying the sms sending code:

port.WriteLine("AT+CMGS=\"" + PhNumber + "\"");
port.Write(Message + char.ConvertFromUtf32(26));

score 2 · Answer 3 · answered Oct 07 '15 at 12:51

Try it this way.. You are not opening the connection to the serial port. I have tried it and it is working fine for me.

 private void button1_Click(object sender, EventArgs e)
 {
     this.serialPort = new SerialPort();
     this.serialPort.PortName = "COM5";
     this.serialPort.BaudRate = 9600;
     this.serialPort.Parity = Parity.None;
     this.serialPort.DataBits = 8;
     this.serialPort.StopBits = StopBits.One;
     this.serialPort.Handshake = Handshake.RequestToSend;
     this.serialPort.DtrEnable = true;
     this.serialPort.RtsEnable = true;
     this.serialPort.NewLine = System.Environment.NewLine;
     serialPort.Open();
     send_sms();
 }
 public bool send_sms()
 {
     String SMSMessage = "gsm MESSAGE FROM .NET C#";
     String CellNumber = "+9233333333333";
     String messageToSend = null;
     if (SMSMessage.Length <= 160)
     {
         messageToSend = SMSMessage;
     }
     else
     {
         messageToSend = SMSMessage.Substring(0, 160);
     }
     if (serialPort.IsOpen)
     {
         this.serialPort.WriteLine(@"AT" + (char)(13));
         Thread.Sleep(200);
         this.serialPort.WriteLine("AT+CMGF=1" + (char)(13));
         Thread.Sleep(200);
         this.serialPort.WriteLine(@"AT+CMGS=""" + CellNumber + @"""" + (char)(13));
         Thread.Sleep(200);
         this.serialPort.WriteLine(SMSMessage + (char)(26));
         return true;
         }
     return false;
 }

Am connecting my android phone with the USB cable and am not finding it under "ports" rather it is under "portable devices", because of this am not able to test the SMS feature. How can I enable COM port? — Ds Arjun, Mar 30 '18 at 10:12

AT commands Send/receive SMS

3 Answers3

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