Hi there!
This is very unrelated, but you all have very good ideas, so please let me ask you something.
I have a (landline) phone and a bluetooth headset. Unfortunately, my phone does not have bluetooth. I could imagine, that it has to be easy to just add a small device to the 2.5mm jack of the phone, which connects to the bluetooth headset. I know that at least there have been such devices (like the Jabra A210), but I cant find anything! Any help finding something like this is much appreciated! Thanks!