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.NET Phone Communication Library Part I - Retrieve Phone Settings

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Dec 5, 2006

CPOL

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Communicate with GSM modem phones using AT commands

Sample Image - phoneat.jpg

Introduction

This article describes a way of communicating with your mobile phone using AT commands. Normally, a GSM compatible mobile phone will have a built-in modem, which we can communicate using AT commands. The AT command set should be common among all the handphone manufacturers including Nokia, Sony Ericsson, Siemen, and Motorola, although slight differences exist.

In this article, I will use an open source .NET phone communication library to show you the various ways of communicating with your mobile phone. The library is available here.

Getting started

Before we can communicate with the GSM phone, a connection must be established first. The connection can be either serial, bluetooth, or irDA. As long as we can connect to the phone, it is fine.

In this article, I established a bluetooth connection with my mobile phone. Firstly, I create a partnership between my laptop and my Nokia mobile phone, and then select the Bluetooth Serial Port service on my mobile phone. The configuration may wary depending on the Bluetooth software and the driver for your modem. If everything is okay, you should be able to see a Bluetooth modem configured in your device manager. Successful configuration will have the following:

Take note that in my configuration, the COM port configured is COM9 and the baud rate is 115200. These settings will be used to connect to the mobile phone.

Test the configuration

After the Bluetooth connection is set up, we can use HyperTerminal to try to send AT commands to make sure the connection is okay.

As you can see, AT commands start with the word "AT". E.g., "ATE1" means echo the command typed locally, "AT+CGMM" displays the handphone model, and "AT+CSCA?" displays the SMSC configured in the mobile phone.

If everything is okay now, you can use the sample code attached in this article to retrieve various handphone settings. The results will be similiar to the screenshot displayed at the top of this article. Take note that different handsets may support different AT command sets. Certain AT commands may not be available in certain handsets.

The code in the solution is quite straightforward. It makes use of the open source library atSMS to retrieve various phone configurations by sending AT commands. You can read the list of the APIs available in the documentation and sample provided.

  If cboComPort.Text = String.Empty Then
            MsgBox("COM Port must be selected", MsgBoxStyle.Information)
            Return
        End If

        Dim oGsmModem As New GSMModem

        oGsmModem.Port = cboComPort.Text

        If cboBaudRate.Text <> String.Empty Then
            oGsmModem.BaudRate = Convert.ToInt32(cboBaudRate.Text)
        End If

        If cboDataBit.Text <> String.Empty Then
            oGsmModem.DataBits = Convert.ToInt32(cboDataBit.Text)
        End If

        If cboStopBit.Text <> String.Empty Then
            Select Case cboStopBit.Text
                Case "1"
                    oGsmModem.StopBits = Common.EnumStopBits.One
                Case "1.5"
                    oGsmModem.StopBits = Common.EnumStopBits.OnePointFive
                Case "2"
                    oGsmModem.StopBits = Common.EnumStopBits.Two
            End Select
        End If

        If cboFlowControl.Text <> String.Empty Then
            Select Case cboFlowControl.Text
                Case "None"
                    oGsmModem.FlowControl = Common.EnumFlowControl.None
                Case "Hardware"
                    oGsmModem.FlowControl = Common.EnumFlowControl.RTS_CTS
                Case "Xon/Xoff"
                    oGsmModem.FlowControl = Common.EnumFlowControl.Xon_Xoff
            End Select
        End If

        Try
            oGsmModem.Connect()
        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Critical)
            Return
        End Try

        Try
            txtRevision.Text = oGsmModem.Revision
        Catch ex As Exception
            txtRevision.Text = "Not supported"
        End Try

        Try
            txtIMSI.Text = oGsmModem.IMSI
        Catch ex As Exception
            txtIMSI.Text = "Not supported"
        End Try

        Try
            txtIMEI.Text = oGsmModem.IMEI
        Catch ex As Exception
            txtIMEI.Text = "Not supported"
        End Try

        Try
            txtModel.Text = oGsmModem.PhoneModel
        Catch ex As Exception
            txtModel.Text = "Not supported"
        End Try

        Try
            txtManufacturer.Text = oGsmModem.Manufacturer
        Catch ex As Exception
            txtManufacturer.Text = "Not supported"
        End Try

     

        Try
            txtSMSC.Text = oGsmModem.SMSC
        Catch ex As Exception
            txtSMSC.Text = "Not supported"
        End Try


        Try
            Dim rssi As Rssi = oGsmModem.GetRssi
            txtSignal.Text = rssi.Current & " of " & rssi.Maximum
        Catch ex As Exception
            txtSignal.Text = "Not supported"
        End Try

        Try
            Dim storages() As Storage = oGsmModem.GetStorageSetting
            Dim i As Integer
            txtSupportedStorage.Text = String.Empty
            For i = 0 To storages.Length - 1
                Dim storage As Storage = storages(i)
                txtSupportedStorage.Text += storage.Name & "(" &_
                    storage.Used & "/" & storage.Total & "), "
            Next
        Catch ex As Exception
            txtSupportedStorage.Text = "Not supported"
        End Try

        Try
            Dim loc As Location = oGsmModem.GetLocation
            txtLocation.Text = "Cell Id: " & loc.CellID & _
                 ", MNC: " & loc.MNC & ", MCC: " & _
                 loc.MCC & ", LAI: " & loc.LAI
        Catch ex As Exception
            txtLocation.Text = "Not supported"
        End Try

        Try
            txtPhoneNumber.Text = oGsmModem.MSISDN
        Catch ex As Exception
            txtPhoneNumber.Text = "Not supported"
        End Try

        Try
            Dim battery As Battery = oGsmModem.GetBatteryLevel
            txtBattery.Text = battery.BatteryLevel & "/" & _
                              battery.MaximumLevel & "(Charging: " &_
                              battery.BatteryCharged & ")"
        Catch ex As Exception
            txtBattery.Text = "Not supported"
        End Try

In future articles, I will show you how to send ASCII and Unicode SMS using AT commands and the open source library. So stay tuned...