Module HWI_Interface
    Public Event Data_Receive(ByVal Data As String)
    Dim Sender As Object
 
    Public Sub InitializeRS232()
        HWI_Interface.RS232 = New System.IO.Ports.SerialPort()
        RS232.BaudRate = 57600
        RS232.Open()
    End Sub
 
    Sub DataSend(ByVal sender As Object, ByVal Kommando As String)
        HWI_Interface.Sender = sender
        RS232.WriteLine(Kommando)
    End Sub
 
    Private Sub Date_Receive(ByVal sender As Object, ByVal e As _
      System.IO.Ports.SerialDataReceivedEventArgs) Handles RS232.DataReceived
        RaiseEvent Data_Receive(RS232.ReadLine)
    End Sub
 
    Friend WithEvents RS232 As System.IO.Ports.SerialPort
End Module

Public Class Form1
    Public Event Receive_Data(ByVal Data As String)
 
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) _
      Handles Me.Load
        AddHandler Receive_Data, AddressOf DatenErhalten
        InitializeRS232()
        DataSend(Me, "test")
 
    End Sub
 
    Private Sub DatenErhalten(ByVal Daten As String)
        'Hierhin sollen die Daten zurück
        MsgBox("Daten erhalten:" & Daten)
    End Sub
End Class