The circuitry inside a VacuTrace is entirely analog. In hindsight, this was a most difficult approach. Would have been much easier to use a PIC or some other microcontroller. The side benefit would have been a serial port to read out digital data to a PC. That would have been cool. Oh well.
The common way to get "digitized" curves is to take pictures of the oscilloscope display with a digital camera. Although this works quite well, it still does not capture the raw XY numerical data.
Some digital scopes work fine (must have XY capability) and can be read by a PC. They are costly. I recently discovered this PC-based digital scope that will work
It is cheap, and most importantly, it samples both channels simultaneously. The problem with 99% of this type of scope is that they alternately sample channels - and that leads to skew and errors.
Here's info on the $189 USB scope for VacuTrace:http://www.usb-instruments.com/hardware-ds2200.html
It can be purchased in the US at http://www.saelig.com
. I plan on buying one of these soon, hopefully in time for VSAC.