Public Class Klasse_Serielle_Verbindung
        'Zwei Variablen für eine bzw. Zwei Antworten
        Private WithEvents Serial_Port_COM1_Eine_Antwort As New _
          System.IO.Ports.SerialPort
        'Ruft Datenauswertung auf 
        Delegate Sub ShowRDataCallback_Eine_Antwort(ByVal Text As String)
Private Function open_serial_port(ByRef serial_port As _
  System.IO.Ports.SerialPort) As Boolean
            Try
                serial_port.Open()
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
            Return serial_port.IsOpen
        End Function
'****************************Serial Port Schreiben*********************
        Public Function write_serial_port_eine_antwort(ByVal text As String) As _
          Boolean
            If open_serial_port(Serial_Port_COM1_Eine_Antwort) Then
                ' löschender Ein- und Ausgangspuffer
                Serial_Port_COM1_Eine_Antwort.DiscardInBuffer()
                Serial_Port_COM1_Eine_Antwort.DiscardOutBuffer()
                text += Chr(13) + Chr(10)
                Try
                    Serial_Port_COM1_Eine_Antwort.Write(text)

Return True
                    Exit Function
                Catch ex As Exception
                    MsgBox(ex.Message)
                End Try
            End If
        End Function
'****************************Eine Antwort lesen************************
        Private Sub get_serial_data_handler_Eine_Antwort(ByVal sender As _
          Object, _
                                                         ByVal e As _
                                                         System.IO.Ports.Serial_
                                                         DataReceivedEventArgs) _
                                                         Handles _
                                                         Serial_Port_COM1_Eine__
                                                         Antwort.DataReceived
            Select Case e.EventType
                Case IO.Ports.SerialData.Chars
                    Dim strBuffer As String
                    Dim MyDelegate As New ShowRDataCallback_Eine_Antwort( _
                      AddressOf serielle_daten_auswerten_Eine_Antwort)
 
                    strBuffer = Serial_Port_COM1_Eine_Antwort.ReadLine
                    MyDelegate.Invoke(strBuffer)
                Case IO.Ports.SerialData.Eof
                Case Else
            End Select
        End Sub
 
        Private Function serielle_daten_auswerten_Eine_Antwort(ByVal _
          empfangener_text As String) As String
            Dim Empfangene_Antwort As String
 
            Empfangene_Antwort = Replace(Replace(empfangener_text, Chr(13), _
              ""), Chr(10), "")
            Select Case Empfangene_Antwort.ToUpper
                Case "BUSY"
                Case Else
                    Return Empfangene_Antwort
                    Exit Function
            End Select
 
            Return Nothing
        End Function
End Class