iPhone as a trunk

Hi I saw a Nerd Vittles article from last year about an iPhone proximity idea, phone rings when in the office and routes to iPhone when out of the office automatically.
that was for…Trixbox so I have FreePBX installed can I do this with it ? I am sure I can are there any updated instructions ??
Also what about setting up an iPhone as a trunk to route mobile calls ??

this sounds like a blue ooth script - maybe using findme/followme ? i suspect that the trick would be to get BT working with you iphone (or any phone) then using this BT connection as a trunk . i remember reading about this a while ago , but i never played with it i use a Snom M3 when i an in the office or our workshop , and i just ring my iphone when i am off-site.

yes it’s bluetooth

Would a cell phone gateway be a bit more reliable than bluetooth?