Hello,
The Wavespeed/S is a very old product, so there could be issues with Windows 7. I think Win XP should be fine. it sounds like you're asking for the latest version of the software.
On our website, I found this:
http://ftp1.digi.com/support/utilities/wvspdcfg.zip
It's been so long since I worked on this product, I don't recall if this is all that's required. Please let me know if this helps or not.