Hi Larry,
sorry for the late response - somehow I wasn't notified about the two replies. Or I accidentally deleted the mails 
dunno
Now I get what you are talking about. Ok. But just as a question: if I don't want the data to be logged I would just stop sending the data from my Arduino to the serial port :-X I am a bit unsure whether to blow up code or not by adding commands .... a screw it - it will be added! "The customer is always right" 
I will however add a "Pause Logging" feature in the PLX DAQ UI as well thus one can keep being connected to the Arduino but pause logging from PC side. Both features go hand in hand.
Beep is good as well.
Timer I have to check as I said I never looked at it before. But many thanks for providing a code preview.
I hope I will find time for the next version before Christmas.
@CBJARL: thanks a lot! 