Thank you for your post.
Yes - the ADC-212/50 will work on windows XP, I have used it hear on XP many times.
The transfer speed will vary depending on many things including the operating system. On a windows 98 maching you could be looking at 100kHz, however on NT this is likely to be lower.
A calibrated unit shows you exactly what the errors factors were when calibrated. The calibration is valid for one year. All of our products are covered by a 2 year warranty, calibration does not extend this.
Hope this helps