'///////////////////////////////////////////////
'SMS Class
'
' Class for sending SMS with return status
' (C)opyright 2011 by www.michael-yap.com
' All Rights Reserved.
'///////////////////////////////////////////////
 
Option Explicit On
Imports System
Imports System.Threading
Imports System.ComponentModel
Imports System.Windows.Forms
Imports System.IO.Ports
 
Public Class SMS
    Private WithEvents SMSPort As SerialPort
    Public receiveNow As AutoResetEvent
 
    Public Sub New(ByRef COMMPORT As String)
        receiveNow = New AutoResetEvent(False)
 
        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
 
        AddHandler SMSPort.DataReceived, AddressOf port_DataReceived
 
    End Sub
 
    Public Sub SendSMS(ByVal CellNumber As String,
        ByVal SMSMessage As String)
        Dim MyMessage As String = Nothing
        'Check if Message Length < = 160
 
        If SMSMessage.Length <= 160 Then             MyMessage = SMSMessage         Else             MyMessage = Mid(SMSMessage, 1, 160)         End If         If IsOpen = True Then             Dim recievedData As String = ExecCommand("AT", 300, "No phone connected")             recievedData = ExecCommand("AT+CMGF=1", 300, "Failed to set message format.")             Dim command As String = "AT+CMGS=" & CellNumber & vbCr             recievedData = ExecCommand(command, 300, "Failed to accept phoneNo")             command = MyMessage + Char.ConvertFromUtf32(26) + "\r"             recievedData = ExecCommand(command, 4000, "Failed to send message")         End If     End Sub     Private Function ExecCommand(ByVal command As String, ByVal responseTimeout As Integer, ByVal errorMessage As String) As String         Try             SMSPort.DiscardOutBuffer()             SMSPort.DiscardInBuffer()             receiveNow.Reset()             SMSPort.WriteLine(command)             Dim input As String = ReadResponse(responseTimeout)             If ((input.Length = 0) Or ((Not input.EndsWith("> ")) And (Not input.Contains("OK")))) Then
                Throw New ApplicationException("No success message was received.")
            End If
 
            Return input
 
        Catch ex As Exception
            Throw ex
        End Try
 
    End Function
 
    Private Sub port_DataReceived(ByVal sender As Object, e As SerialDataReceivedEventArgs)
        Try
            If e.EventType = SerialData.Chars Then
                receiveNow.Set()
            End If
        Catch ex As Exception
 
        End Try
    End Sub
 
    Public Function ReadResponse(ByVal timeout As Integer) As String
        Dim buffer As String = String.Empty
 
        Try
            Do While (Not buffer.Contains("OK") And Not buffer.EndsWith("> ") And Not buffer.Contains("ERROR"))
                If receiveNow.WaitOne(timeout, False) Then
                    Thread.Sleep(500) ' you need to adjust this settings depending on how your modem can
                                              ' able to get response to the provider, its recommended also to use the
                                              ' thread timeout instead of adding this. sorry its a quick fix :(
                    buffer += SMSPort.ReadExisting()
                Else
                    If (buffer.Length > 0) Then
                        Throw New ApplicationException("Response received is incomplete.")
                    Else
                        Throw New ApplicationException("No data received from phone.")
                    End If
                End If
 
            Loop
 
        Catch ex As Exception
            Throw ex
        End Try
 
        Return buffer
    End Function
 
    Public ReadOnly Property IsOpen() As Boolean
        Get
            If SMSPort.IsOpen = True Then
                IsOpen = True
            Else
                IsOpen = False
            End If
        End Get
    End Property
 
    Public Sub Open()
        If IsOpen = False Then
            SMSPort.Open()
        End If
    End Sub
 
    Public Sub Close()
        If IsOpen = True Then
            SMSPort.Close()
        End If
    End Sub
 
End Class

            'send sms
            Dim Retries as Integer=1
            Dim SMSEngine = New SMS("COM3") 'replace with your actual modem USB/Serial Port
            Dim validnumber as String = "+639221234567" ' replace with your number, be sure it includes
                                                                          ' the country code
 
            SMSEngine.Open()
 
            Try
                SMSEngine.SendSMS(validnumber, textmessage)
            Catch ex As Exception
                If Retries >= 3 Then
                    Console.Write("Failed after 3 retries: " & ex.Message) 'you can customize this base on the failed result status
                Else
                    Retries + = 1
                End If
            End Try
 
            SMSEngine.Close()