AT Commands to Send SMS not working in Windows 8.1

Question

I have been researching now for more than two days, trying to make an app to send SMS using AT Command, I implemented few tutorials and projects available on web. Unluckily, none of them worked.

[https://docs.google.com/document/d/1VfBbMcKZsutP8Cwg2iu7Rqiyccks1J6N2ZEbkbxnCTU/preview ] This code gives me Command executed, but message is not sent.

Then I tried another project (I am using C# and Visual Studio 2013), which have following files, After execution the status is changes to Message Sent, but I do not receive Message. I am using HUAWEI Mobile Connect - 3G Application Interface GSM Modem

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace CSharp_SMS
{
static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form_SMS_Sender());
    }
}
}

Form1.cs

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

        _serialPort = new SerialPort("COM17", 19200);   //Replace "COM7" with corresponding port name

        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();
    }
}
}

Is there problem in the program? Did I missed any thing? Or, there's problem to run this in Windows 8.1, cause I also found that there is a program called MS HyperTerminal, which part of that is not clear to me.

Answer 1

I used AT Commands in following format and it works.

public bool sendMsg(string smsid, string PhoneNo, string Message, string from, string to)
{
    string recievedData;
    bool isSend = false;
    string text = "Hello " + to + ",\n" + Message + "\n\n" + from;
    if (!port.IsOpen)                
        port = OpenPort();
    recievedData = ExecCommand(port, "AT+CMGF=1", 400, "Failed to set message format.");

    try
    {
        //string recievedData; // = ExecCommand(port, "AT", 3000, "No phone connected");
        String command = "AT+CMGS=\"" + PhoneNo + "\"";
        recievedData = ExecCommand(port, command, 1000, "Failed to accept phoneNo");
        command = text + char.ConvertFromUtf32(26) + "\r";
        recievedData = ExecCommand(port, command, 1000, "Failed to send message");
        if (recievedData.Contains("OK"))
        {
            isSend = true;                  
        }
        else if (recievedData.Contains("ERROR"))
        {
            isSend = false;                
        }
    }
    catch (Exception ex)
    {
        MyLog.Write(new LogPacket(ex, DateTime.Now));
    }
    return isSend;
}

Answer 2

I use SMSPDUlib

and code

    private const string LT = "\r\n";

    public void Auth(string pin)
    {
        lock (smsSendSync)
        {
            //Check if gateway is alive
            lastSplit = SplitResponse(SendCommand("AT"));
            if (!(lastSplit[lastSplit.Length - 1] == "OK"))
                throw new OperationCanceledException("AT connection failed");

            //Echo ON
            lastSplit = SplitResponse(SendCommand("ATE1"));
            if (!(lastSplit[lastSplit.Length - 1] == "OK"))
                throw new OperationCanceledException("ATE command failed");

            //Check echo
            lastSplit = SplitResponse(SendCommand("AT"));
            if (!(lastSplit.Length == 2 && lastSplit[1] == "OK"))
                throw new OperationCanceledException("AT command failed");

            //Verbose error reporting
            lastSplit = SplitResponse(SendCommand("AT+CMEE=2"));
            if (!(lastSplit.Length == 2 && lastSplit[1] == "OK"))
                throw new OperationCanceledException("AT+CMEE command failed");

            //Enter a PIN
            lastSplit = SplitResponse(SendCommand("AT+CPIN?"));
            if (!(lastSplit.Length == 3 && lastSplit[2] == "OK"))
                throw new OperationCanceledException("AT+CPIN? command failed");
            switch (lastSplit[1])
            {
                case "+CPIN: READY": //no need to enter PIN
                    break;
                case "+CPIN: SIM PIN": //PIN requested
                    lastSplit = SplitResponse(SendCommand("AT+CPIN=" + pin));
                    string m_receiveData = String.Empty;
                    WaitForResponse(out m_receiveData);
                    if (m_receiveData == String.Empty)
                        throw new OperationCanceledException("PIN authentification timed out");
                    break;
                default:
                    throw new OperationCanceledException("Unknown PIN request");
            }
            //Check if registered to a GSM network
            lastSplit = SplitResponse(SendCommand("AT+CREG?"));
            if (!(lastSplit.Length == 3 && lastSplit[2] == "OK"))
                throw new OperationCanceledException("AT+CREG? command failed");
            lastSplit = lastSplit[1].Split(new string[] {" ", ","}, StringSplitOptions.RemoveEmptyEntries);
            if (!(lastSplit[2] == "1" || lastSplit[2] == "5"))
                throw new OperationCanceledException("Not registered to a GSM network");
            Debug.WriteLine("Authentification successfull");
        }
    }

    private string[] SplitResponse(string response)
    {
        string[] split = response.Split(new string[] { LT }, StringSplitOptions.RemoveEmptyEntries);
        for (int i = 0; i < split.Length; i++)
            split[i] = split[i].Trim();
        return split;
    }

    public string SendCommand(string command)
    {
        string m_receiveData = string.Empty;
        smsPort.ReadExisting();     //throw away any garbage
        smsPort.WriteLine(command + LT);
        WaitForResponse(out m_receiveData);
        //Debug.WriteLine(m_receiveData);
        return m_receiveData;
    }

    public string SendSms2(string phoneNumber, string message, bool flashMsg, SMS.SMSEncoding encoding)
    {
        if (phoneNumber.StartsWith("00"))
            phoneNumber = "+" + phoneNumber.Substring(2);
        if (phoneNumber.StartsWith("0"))
            //replace with your national code
            phoneNumber = "+386" + phoneNumber.Substring(1); 
        string StatusMessage = string.Empty;
        SMS sms = new SMS();                            //Compose PDU SMS
        sms.Direction = SMSDirection.Submited;          //Setting direction of sms
        sms.Flash = flashMsg;                           //Sets the flash property of SMS
        sms.PhoneNumber = phoneNumber.Replace(" ","");  //Set the recipient number
        sms.MessageEncoding = encoding;                 //Sets the Message encoding for this SMS
        sms.ValidityPeriod = new TimeSpan(4, 0, 0, 0);  //Set validity period
        sms.Message = message;                          //Set the SMS Message text
        string sequence = sms.Compose() + CtrlZ;        //Compile PDU unit
        string sequenceLength = ((sequence.Length - 3) / 2).ToString();
        lock (smsSendSync)
        {
            StatusMessage = SendCommand("AT+CMGS=" + sequenceLength) + " ";
            Thread.Sleep(500);
            StatusMessage += SendCommand(sequence);
        }
        Debug.WriteLine(StatusMessage);
        if (StatusMessage.Contains("ERROR"))
            throw new OperationCanceledException("Error sending SMS");
        return StatusMessage;
    }

Use Auth() to initialize modem and SendSms2() to send a SMS.