Private Sub cmdSend_Click()
    Dim Buffer As String
    
    COM2.Output = Chr$(34) & txtTestText.Text & Chr$(34) & Chr$(13)
    
    Do
        DoEvents
        Buffer = Buffer & COM2.Input
    Loop Until InStr(Buffer, "OK" & vbCrLf)
    
    COM2.PortOpen = False
    cmdOpenCOM2.Enabled = True
End Sub

Private Sub cmdOpenCOM2_Click()
    COM2.CommPort = 2
    COM2.Settings = "9600,N,8,1"
    COM2.PortOpen = True
    cmdOpenCOM2.Enabled = False
End Sub