find gsm modem com port using vb.net - vb.net

Question

how to find gsm modem com port using vb.net? i writing this code :
Imports System
Imports System.Threading
Imports System.ComponentModel
Imports System.IO.Ports
Public Class Form1
'connect your mobile/GSM modem to PC,
'then go in device manager and check under ports which COM port has been slected
'if say com1 is there then put com2 in following statement
Dim SMSEngine As New SMSCOMMS("COM5")
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
End Class
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 = 19200
.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+CMGS=""[phone]""" & vbCrLf) ' enter the mobile number whom you want to send the SMS
_ContSMS = False
SMSPort.WriteLine("SUCCESS" & vbCrLf & Chr(26)) 'SMS sending
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
but in this code :
Dim SMSEngine As New SMSCOMMS("COM5")
i need to know which com port that my modem gsm was connected, so i need code that can automatically find com port, can someone help me please?
thank you very much.
nb : i use visual basic 2012 (vb.net)

Answer 1

like others said, you will have to loop all ports and check whether you can connect use Rate/port to connect to the GSM modem. Here is a library, it is c#, but you can download the source code to see how it works.
http://www.scampers.org/steve/sms/libraries.htm

Answer 2

The only way to do this automatically without having to either select the COM port in your program interface or hard code the port number is to attempt to open all available COM ports, and send each one some kind of status command and listen (with a short timeout period) for a reply that only the GSM modem would return. Of course, this means you may send weird commands to other serial devices, if any, that are attached to the computer, but I'm guessing in your case it will be the only serial port with anything attached.
See here for the function to get the list of serial port names on the current computer.

Answer 3

Here's the Code to Find Attached modems and their Attributes in vb.net.
Dim searcher As New ManagementObjectSearcher( _
"root\CIMV2", _
"SELECT * FROM Win32_POTSModem")
ComboBox1.Items.Clear()
For Each queryObj As ManagementObject In searcher.Get()
If queryObj("Status") = "OK" Then
modems = queryObj("Description")
baud = queryObj("MaxBaudRateToSerialPort")
Port = queryObj("AttachedTo")
da.rows.add(1)
da.rows(incount).item(1)=Port
da.rows(incount).item(2)=baud
ComboBox1.Items.Add(modems)
ComboBox1.SelectedIndex = ComboBox1.FindString("Nokia")
If ComboBox1.SelectedItem = "" Then
ComboBox1.SelectedIndex = ComboBox1.FindString("Samsung")
If ComboBox1.SelectedItem = "" Then
ComboBox1.SelectedIndex = 0
End If
End If
End If
intcount+=1
Next
You need to add reference to the System.management assembly and also import the namespace system.management.