Stopwatches not in Sync?????

[dbasnett]

Assuming that the handler isn't doing anything else, try it like this

    Private Sub SerialPort1_DataReceived(sender As Object, _
                                         e As IO.Ports.SerialDataReceivedEventArgs) _
                                     Handles SerialPort1.DataReceived
        If SerialPort1.BytesToRead > 12 Then
            'call to GetData here
        End If
    End Sub