I picked up an unlocked GSM 650 today, and I've been trying to work out the Bluetooth pairing with my Mac, and noticed something odd. The phone has DUN available (without shadowmite's hack, since it's not carrier "enhanced"). If I pair the phone with DUN enabled, then the device profile on the Mac shows DUN as the only service available. It works fine for networking once I got the proper modem script. But I can't send files to the Treo because the other BT profiles aren't detected on the device.

So I tried disabling DUN and repairing the device to my Mac, just as an experiment. When I do this, the DUN profile is not detected (as expected), but the OBEX object push profile is detected, and I can send files from my Mac to the Treo over BT. But I can also do DUN through the Treo using the Internet Connect I set up after the previous pairing (after re-enabling DUN on the Treo, of course). Good end result, but odd overall behavior, and pretty confusing to the casual user.

Then I tried another experiment: I re-paired the Treo to my desktop with the DUN profile enabled. Then I went to the Treo and tried to send an image to my desktop using BT. I could do it, but only if I disable DUN on the Treo first. If I had DUN enabled, I'd choose the BT option to send, and the Treo would silently ignore me and drop back into the application (the camera app, in this case).

I can't find any details on this here, on the general web, at palmOne's support area, or in the manual for the Treo. But I think there are few conclusions:

- Enabling DUN on the Treo not only adds the DUN profile to its BT stack (detected by other devices pairing to it), it removes some if not all of the other profiles the Treo supports. It also apparently disables the runtime use of these profiles on the Treo itself, until DUN is turned off again.

- The most robust sequence in terms of setting up a pairing on a Mac (and possibly on other PCs as well) is to:

1) Pair with the Treo with its DUN option enabled. Set up a network connection setting, test it to make sure it works.

2) Remove the first device pairing, turn off DUN on the Treo, and repair to get the OBEX Object Push profile associated with the pairing on the Mac.

At the end of this, you should have the Treo paired with your Mac, a working DUN option using the Treo, and you'll be able to push files from the Treo to the desktop and vice versa.

Again, this is an unlocked GSM without shadowmite's hack. I'm not sure how his hack will affect the behavior of the Treo BT stack. Maybe someone with a hacked GSM model and a Mac could give this a try.

MODs: This has to do with Bluetooth on the 650, the Treo in general, pairing with Macs and possibly pairing with other desktops as well. So I posted it to the general Treo 650 forum, rather than the "Bluetooth" or "Mac and Treo" forums.