using GSM modem to send SMS

[apple25]

Dear experts,

I am doing my project and I am still new with visual basic. for my project, I need to send SMS using GSM modem using vb.net. I tried to send it using this program, but there is no reaction. I wonder what is wrong with the program. can you please take a look at this program and if anything wrong can you please tell me what it is. thank you for your help.

Imports System
Imports System.Threading
Imports System.ComponentModel
Imports System.IO.Ports

Public Class Form1
'connect mobile/GSM modem to PC,
'then go in device manager and check under ports which COM port has been selected
'if say com1 is there then put com2 in following statement
Dim SMSEngine As New SMSCOMMS("COM23")
Dim i As Integer
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

SMSEngine.Open() 'open the port
SMSEngine.SendSMS() 'send the SMS

End Sub

Public Class SMSCOMMS
Private WithEvents SMSPort As SerialPort
Private SMSThread As Thread
Private ReadThread As Thread
Shared _Continue As Boolean = False
Shared _ContSMS As Boolean = False
Private _Wait As Boolean = False
Shared _ReadPort As Boolean = False
Public Event Sending(ByVal Done As Boolean)
Public Event DataReceived(ByVal Message As String)

Public Sub New(ByRef COMMPORT As String)
'initialize all values
SMSPort = New SerialPort
With SMSPort
.PortName = COMMPORT
.BaudRate = 9600
.Parity = Parity.None
.DataBits = 8
.StopBits = StopBits.One
.Handshake = Handshake.RequestToSend
.DtrEnable = True
.RtsEnable = True
.NewLine = vbCrLf
End With
End Sub
Public Function SendSMS() As Boolean
If SMSPort.IsOpen = True Then
'sending AT commands
SMSPort.WriteLine("AT")
SMSPort.WriteLine("AT+CMGF=1" & vbCrLf) 'set command message format to text mode(1)
SMSPort.WriteLine("AT+CSCA=""+60193900000""" & vbCrLf)
SMSPort.WriteLine("AT+CMGS= + TextBox1.text + " & vbCrLf) ' enter the mobile number to send the SMS
_ContSMS = False
SMSPort.WriteLine("+ TextBox1.text +" & vbCrLf & Chr(26)) 'SMS sending
MessageBox.Show(":send")
SMSPort.Close()
End If
End Function

Public Sub Open()
If Not (SMSPort.IsOpen = True) Then
SMSPort.Open()
End If
End Sub

Public Sub Close()
If SMSPort.IsOpen = True Then
SMSPort.Close()
End If
End Sub
End Class

[bensonsearch]

Hi and welcome to the forums.
Firstly when pasting code please wrap it in code tags, there is a button for them in the advanced editor, this makes things easier to read as it comes out like:

this is where code goes

Now with the code. The first thing is making sure the modem can actually accept AT commands. Some modems need to be put into particular modes etc etc, Do you get any errors? what part doesn't work? Is the modem connected and assigned a COM port number?

Start there and let us know

[2ndmessiah]

looking at your code

'sending AT commands
SMSPort.WriteLine("AT")
SMSPort.WriteLine("AT+CMGF=1" & vbCrLf) 'set command message format to text mode(1)
SMSPort.WriteLine("AT+CSCA=""+60193900000""" & vbCrLf) 
SMSPort.WriteLine("AT+CMGS= + TextBox1.text + " & vbCrLf) ' enter the mobile number to send the SMS
_ContSMS = False
SMSPort.WriteLine("+ TextBox1.text +" & vbCrLf & Chr(26)) 'SMS sending

this line

SMSPort.WriteLine("AT")

is missing carriage return. I dont even think you need this line.

Here

SMSPort.WriteLine("AT+CMGS= + TextBox1.text + " & vbCrLf) ' enter the mobile number to send the SMS
SMSPort.WriteLine("+ TextBox1.text +" & vbCrLf & Chr(26)) 'SMS sending

You are not correctly building the AT command.

this might work.

SMSPort.WriteLine("AT+CMGS=" & TextBox1.text & vbCrLf) ' enter the mobile number to send the SMS
_ContSMS = False
SMSPort.WriteLine(TextBox1.text & vbCrLf & Chr(26)) 'SMS sending

Why are you not checking the responses from the serialport? It would give you a better understanding why things are not working.

Have you tried just sending the AT commands to the GSM modem with term to determine what the correct format is and the response you might expect back from the modem?

[apple25]

thank you for the response...
i'm sorry for the pasting code like that since i'm still new here but i will take a note on that.
i have already make sure the modem can accept the AT commands because i have already tested with hyper terminal and it works.
i have already test the GSM by sending and receiving the sms. the GSM that i used are Siemens TC35. before i running the program i have make sure that the modem is connected and assigned a COM port number which is com24. the problem is, when i tried to send the sms using this program, it does not show any error but the program says is running but does not give any response at all; not message box appeared saying the the sms is sending.

[bensonsearch]

No worries about the tags.

In regards to errors, you aren't catching them so place it in a try/catch end try. You should put in something that reads back any response the modem gives as 2ndmessiah has mentioned

Public Function SendSMS() As Boolean
If SMSPort.IsOpen = True Then
Try
'sending AT commands
SMSPort.WriteLine("AT")
SMSPort.WriteLine("AT+CMGF=1" & vbCrLf) 'set command message format to text mode(1)
SMSPort.WriteLine("AT+CSCA=""+60193900000""" & vbCrLf) 
SMSPort.WriteLine("AT+CMGS= + TextBox1.text + " & vbCrLf) ' enter the mobile number to send the SMS
_ContSMS = False
SMSPort.WriteLine("+ TextBox1.text +" & vbCrLf & Chr(26)) 'SMS sending
If SMSPort.BytesToRead > 0 Then
    Console.WriteLine(SMSPort.ReadExisting)
End If 'i have not tested this nor do i know if its even going to work
MessageBox.Show(":send")
SMSPort.Close()
Catch ex as Exception
msgbox(ex.message)
End Try
End If
End Function

[2ndmessiah]

Your code is opening COM23. In your last post you said it is COM24.
A minor oversight that might be causing you a problem.