Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        With SerialPort1
            .PortName = "COM1"
            .BaudRate = "19200"
            .Parity = System.IO.Ports.Parity.None
            .DataBits = "8"
            .StopBits = "1"
        End With
    End Sub
    Public Function senden(ByVal box)
        SerialPort1.Open()
        Dim Zeichenfolge(3) As Byte
        Dim IncommingData As String = SerialPort1.ReadExisting
 
 
        Zeichenfolge(0) = "3"
        Zeichenfolge(1) = "0"
        Zeichenfolge(2) = box
 
        Zeichenfolge(3) = Zeichenfolge(0) Xor Zeichenfolge(1) Xor Zeichenfolge( _
          2)
 
 
 
        SerialPort1.Write(Zeichenfolge, 0, 4)
        SerialPort1.Close()
 
    End Function
 
    Private Sub r1_Checked(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles r1.CheckedChanged
        senden(TextBox1.Text)
    End Sub
End Class

Public Function RShiftLong(ByVal Value As Long, ByVal Shift As Integer) As Long
    Dim hi As Long
    MakeOnBits
    If (Value And &H80000000) Then hi = &H40000000
 
    RShiftLong = (Value And &H7FFFFFFE) \ (2 ^ Shift)
    RShiftLong = (RShiftLong Or (hi \ (2 ^ (Shift - 1))))
End Function
 
Private Sub MakeOnBits()
    Dim j As Integer, v As Long
    For j = 0 To 30
        v = v + (2 ^ j)
        OnBits(j) = v
    Next j
    OnBits(j) = v + &H80000000
End Sub