It's here! And it works great with the Nokia 770!

In case any other readers are going to try it, here's how to make it work (there are no instructions for such a setup, in the Nokia 770 booklet nor this bluetooth modem's documentation, so it wasn't smooth as silk, getting it to work).

In Control Panel | Phone | New, it was very easy to get the two gadgets paired together via bluetooth. Then came the hard part.

In Control Panel | Connectivity | Connections | New, I didn't know what to pick, because the manual-writers for both devices apparently don't expect anyone to ever do this. So I used trial and error to figure out how to set it up. The correct answers appear to be: Connection type "Data call", Cellular network is the next question, which is silly, I'm using a dial-up network, not a cellular one, but nevertheless the only answer that worked here was CDMA. Once I tried that one, everything was golden.