Public Class form_main
   'Public ....
    Public ticker As Int32
    Private Sub form_main_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
    Me.TabControl1.Hide()  'Das Tabblatt verstecken
     jetzt erstmal Anschluß suchen:
    If SerialPort1.IsOpen Then SerialPort1.Close() 'falls offen, schließen
 
    For Each sp As String In My.Computer.Ports.SerialPortNames
         If Microsoft.VisualBasic.Left(sp, 3) = "COM" Then
             If OpenSerialPort(sp) = True Then
               ' nun teststring senden:
                 CallDataSlave(&H10)  ' funktioniert...
                 ticker = 0
                 Timer1.Interval = 10  'timer starten, 10ms/tick
                 Timer1.Enabled = True
 
                 While ticker < 10 
' hier haengt es
                 End While
 
                 Timer1.Enabled = False  'timer wieder stoppen und dann folgt 
                 ' der Rest..
 
    End Sub
    Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) _
      Handles Timer1.Tick
        ticker += 1
    End Sub
'... Rest des Codes
end Class