Device IS paired with the MacBook (white on 10.5.5) but won't connect?

Question

Here is the deal- we have two MacBook Pros (one on 10.4.11 and the other on 10.5.4) and one MacBook (on 10.5.5) and all can see and be paired with the Nokia 6220 classic (mobile phone) but the MacBook refuses connection.
Now, I am not used to all this pairing malarky- I remember when your bluetooth device was found and connected automatically "just like that" back in the good old days. I cannot figure out why, if paired successfully, the MacBook will not just connect.
I am assuming that "pairing" is just the security formality between two devices and that IT relies on the ability of two devices to see each other.
So- if that was performed successfully (and it was) and the Nokia's bluetooth is on and working (was able to send a file to the MacBook Pro with 10.5.4 in the same room as a test) and so is the MacBook's bluetooth (it sent a file to the MacBook Pro as well) then where is the problem?
Notably- the drop down list of the MacBook we are trying to send files to shows three devices and I am assuming that this is like "favourites"? One of the devices on the drop down IS the Nokia 6220 classic mobile phone but it is the one which does not have options (ie a further drop down menu) but the one MacBook Pro we DID send to doesn't even show up on it!
I am completely lost- I would like to understand pairing and connecting better, and be able to resolve this because the Bluetooth Help files do not deal with this and the manual/site I was directed to did not address this.
Thank you for reading.

Answer 1

Well, both iSync and Bluetooth File Transfers use the same Bluetooth hardware and system software, so it could've been related to your issue...
Anyway, as it works with some Macs, maybe there is some differences between those Macs?
Have you compared the Bluetooth hardware in the Apple System Profiler between the Macs that work, and the Mac that doesn't?
Most Macs with built-in Bluetooth use the CSR (Cambridge Silicon Radio) chipset, but I've seen some (usually more recent Macs) now have a Broadcom chipset.
In the past, the CSR chipset was always more compatible with other devices. If buying an external BT adapter it was always recommended to get one with the CSR chipset, rather than Broadcom.
If Apple have switched BT chip suppliers, you would hope that the new chip is as compatible as the earlier one. But maybe if the BT chips are different between the working and non-working Mac that could be a potential source of the problem. If so, it's likely to require a Bluetooth system software update from Apple to fix.