All windows mobile devices running the bluetooth stack microsoft provides have the same issue. The problem is the phone directly after pairing with something runs a service discovery on it. The N770 does not respond to service discovery requests by default because it runs no bluetooth services.

This fix to this half of the problem is that the user must gain root and issue the command using xterm, as root, "sdpd" to turn on the service discovery protocal daemon so the phone can see that the n770 runs no services and it will correctly pair. SDPD will only run until you reboot the phone, but you don't need it beyond getting the two devices paired.

The second half of the problem is the icd binary shipping in the n770 today contains a PPP chatscript too complex for the simple minded Windows Smartphone. This fix gets more complex.

To fix this problem you have to download a binary from Http://qapf.shackspace.com/icd which a nokia dev provided to me to fix this issue, and you have to overwrite the icd binary on the device with this one. To do this you have to first copy the binary to your device, either via memory card or other methods, then you need to run ps -Aux | grep icd to find the path the current icd binary exists at. After you know where you need to copy your new icd binary to, you need to issue a stop command to osso-ic via its init.d script so the service will stop gracefully. Once that is done you copy the new binary over the old one, and then start the osso-ic service via its init.d script.

I have done these steps myself and it works for the devices. At that point you can make connections via the normal gui tools and dial out to your wireless data provider.