Seems to me that as long as I leave BT enabled on the Treo, and force the 770 to use the Phone connection, the repairing/network connection goes pretty smoothly in subsequent connections. Its not a perfect solution, but works well enough for casual use.

It appears that if I do not add the 770 as a trusted device, I can reliably use the connection as long as I enter a passcode. You just have to make sure that the 770 is not in the "trusted devices" list on the 650. So far, with this, I can reboot the treo and still have it work as a DUN without needing to re-do the connection setup.

Also, it looks like the 770 discovery mode can be turned on: http://bonte.co.uk/myBlog/?p=118
If this works, then perhaps we can pair from the Treo so that we would not have to enter the bt passcode each time.

After the recent 770 ROM upgrade, my T608 is working perfectly for data! Thanks Nokia!

Has anyone figured out a way to pair the 770 with a Sprint Treo 650 that DOES NOT require re-entering the passcode every time? I get a good and reliable connection, but having to enter the passcode on both the Treo and 770 every single time is starting to get old.

i dont know about the treo, but on my phone, there is a setting that i mark "let device connect always"

I've tried everything I could on the Treo and still must enter the passcode when I want to use it.