A question to the wise….
I know this forum has quite a high proportion of tech / IT / cellphone gurus. Perhaps someone can shed light on something that totally baffles me.
Event happened tonight in Austria. I am visiting here, staying at a friend’s place.
The actors are two iPhones, one SE on US per-pay, therefore no cell signal in Austria, the other an old 4s on a UK contract. I use the latter when traveling in Europe.
Here’s what happened:
- the UK phone was sitting on the dining room table, logged into an Austrian cell network and into one of the WiFi networks of the – very big – house.
- the US phone was in the guest room, not logged into any cell network, but logged into a different WiFi network from the UK one.
- I was in the guest room
- a friend called my UK phone (sitting on the opposite end of the house), but my US phone rang and displayed the caller’s name and a message ‘via 172driver’s iPhone’
- the call connected and while the quality wasn’t great, we had a chat and organized a meeting
- the friend who called me is on an Android phone, so no Facetime possible
- there’s no call-forwarding in place between the two phones
Can someone explain how that can work ?? I’m totally stumped.
It is all linked these days via your iTunes account…
I don’t know the answer but I bet it is the same as how somebody I know got a divorce because he could not keep his trousers far above his ankles, and his wife found out because the SMS messages between his Iphone and the phone of his mistress ended up on a Mac which he shared with his wife 
Actually not via your iTunes account but via your iCloud account (they can but do not have to be the same thing). Settings → Phone → Calls on other devices → On/Off.
denopa wrote:
Actually not via your iTunes account but via your iCloud account (they can but do not have to be the same thing). Settings → Phone → Calls on other devices → On/Off.
Thanks, looks like that’s it! The weird thing is that the two phones should be on different iCloud accounts (one UK, one US), but I may well have changed that at some point…
If this system can divert a call to a phone which at the time has no GSM signal at all, this has to be done as transparent VOIP (hence the usually poor quality) and would be an interesting solution to the rather restricted wifi calling service offered by some networks.
