Send SMS via Nokia Mobile Using AT Commands

Question

I'm trying to send sms with my Nokia cell phone (C1-01) using AT Commands and I can successfully send SMS with this vb.net code.

Button_Send_Click:

Dim SMSPort = New SerialPort
    With SMSPort
        .PortName = "COM2"
        .BaudRate = 9600
        .Parity = Parity.None
        .DataBits = 8
        .StopBits = StopBits.One
        .Handshake = Handshake.None
        .DtrEnable = True
        .RtsEnable = True
        .NewLine = vbCrLf
    End With

    SMSPort.Open()

    SMSPort.Write("AT+CMGF=1" & vbCrLf)
    Threading.Thread.Sleep(200)

    SMSPort.Write("AT+CMGS=" & Chr(34) & TextBox1.Text & Chr(34) & vbCrLf) 'TextBox1.text = Recipient mobile number and chr(34) = "
    Threading.Thread.Sleep(200)

    SMSPort.Write("TEST MESSAGE" & Chr(26)) 'chr(26) = →
    Threading.Thread.Sleep(200)

    MsgBox(SMSPort.ReadExisting())

    SMSPort.Close()

It's working fine for the 1st time, after fire this code I received SMS on my cell phone TEST MESSAGE(Brilliant) BUT when I press send button in second time I received SMS on my cell phone which contains: AT+CMGF=1 AT+CMGS=+92XXYYYYYY TEST MESSAGE

Why in second time it's including "AT Commands i.e AT+CMGF etc.." in SMS? How can I remove unwanted text from this? I have also try SMSPort.DiscardInBuffer() and SMSPort.DiscardOutBuffer() Properties after opening and before closing my serial port (SMSPort) but my issue is not resolving. I have googled alot but all is vain, Please help me to resolve this issue.

Platform: Microsoft Visual Basic 2010 with .NET 2.0

Just curious why you are using AT commands on a Nokia phone. It will be a lot easier if you use a GSM library. I've used a couple of open source libraries and they work fine. I've also done AT commands on a microcontroller connected to a barebone GSM module and the thing is...you'll have to use a couple of delays so the GSM module can catch up with what you're sending to it :) — chris_techno25, Feb 23 '14 at 07:29

score 1 · Answer 1 · edited May 23 '17 at 11:43

First of all, you must seriously redo your AT command handling to

Read and parse the every single response line given back from the modem until you get a final result code. This applies for every single command line invocation, no exceptions whatsoever. See this answer for more details.
Never ever call Threading.Thread.Sleep in any code that handles AT commands. See this answer for more details about the risk of aborting the next command.
For AT+CMGS specifically you also MUST wait for the "\n\r> " response before sending data, see this answer (again) for more details.

Before fixing these fundamental issues you cannot expect any successful behaviour.

Thank you for your answer, But it's too late and I have now working at another project. But Soon I will re-open this project and if your answer will helpful I will accept it. @hlovdal — Muhammad Saqib, Dec 26 '13 at 08:26

score 0 · Answer 2 · answered Mar 22 '14 at 08:52

0

OK, I came across the same issue today, and I solved it by adding "\r\n" to the end of the message, before sending CTRL+Z (char 26). You may try it with just "\n"

answered Mar 22 '14 at 08:52

Ali Yousuf

692
8
23

Thank you for your answer, But it's too late and I am currently working at another project. But Soon I will re-open this project and if your answer will helpful I will definitely accept it. @aly.yousuf7 – Muhammad Saqib Mar 23 '14 at 13:54

score -1 · Answer 3 · answered Mar 05 '14 at 10:28

Try this

Dim SMSPort = New SerialPort
    With SMSPort
        .PortName = "COM2"
        .BaudRate = 9600
        .Parity = Parity.None
        .DataBits = 8
        .StopBits = StopBits.One
        .Handshake = Handshake.None
        .DtrEnable = True
        .RtsEnable = True
        .NewLine = vbCrLf
End With

SMSPort.Open()

SMSPort.WriteLine("AT" & Chr(13))
Threading.Thread.Sleep(200)

SMSPort.WriteLine("AT+CMGF=1" & Chr(13))
Threading.Thread.Sleep(200)

SMSPort.WriteLine("AT+CMGS=" & Chr(34) & TextBox1.Text & Chr(34)) 
Threading.Thread.Sleep(200)

SMSPort.WriteLine("TEST MESSAGE" & Chr(26))
Threading.Thread.Sleep(200)

MsgBox(SMSPort.ReadExisting())

SMSPort.Close()

Add SMSPort.WriteLine("AT" & Chr(13)) and I replaced Write with WriteLine and removed vbCrlf. Also added Chr(13) to SMSPort.WriteLine("AT+CMGF=1")

Send SMS via Nokia Mobile Using AT Commands

3 Answers3

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