I'm trying to answer it, but get no submit button.
I don't have time now, so leaving the answer here. Could someone point it out to the asker?
Comment for Q10236310...
Visual basic is the easiest.
You add to your toolbox a "Communications" control.
You get a nice little picture of a "telephone" on your toolbox.
You drag it onto the form, set it's properties, and start coding.
The VB helps you along the way.
MSDN (The Microsoft help site) gives a very comprehensive and easy explanation of serial ports and using this "Communications control".
Each device (like your voltage meter) comes with documentation, telling you what you send the device to set it up, and what you will be getting back.
This you can download from Tektronix site: www.tek.com
Choose the tds2x32.zip, download and read the expamples.
Have fun, Moshe