Rs232 med Handshaking

Do Until countt = counttt  ' Loop until end of file.
            AxMSComm1.RTSEnable = True
            rs232cts = AxMSComm1.CTSHolding()
            If rs232cts = True Then
                AxMSComm1.Output = bkod(countt) & Chr(13) & Chr(10)
                buf_1 = AxMSComm1.Input
                If CheckBox1.CheckState = 1 Then
                    ListBox1.Items.Add(bkod(countt) & Chr(13) & Chr(10))
                End If
                countt = countt + 1
                ProgressBar2.Value = countt
            End If
        Loop