That didn't take long.
Last month, AT&T announced its NumberSync initiative; a way to route phone calls over Wi-Fi networks to computers and tablets. The feature is appearing this week in the latest iOS 9.2 beta 2 software.
9to5 Mac spotted and tested the feature after installing the iOS 9.2 beta 2 software on an iPhone.
The setup process looks simple and reminds me of how you enable Wi-Fi Calling on an AT&T iPhone. You'll need to verify your address for emergency 911 services before using NumberSync.
After configuring the function, your iPhone doesn't even need to be on AT&T's cellular network for you to accept or place calls on a supported Mac or iPad.
its testing, 9to5 Mac put a phone in Airplane Mode without any disruption in phone service on the secondary devices.
While this might sound like Continuity in iOS 9, which routes incoming calls to OS X and iOS tablets, it's slightly different.
Continuity relies on your iPhone to notify other devices over Wi-Fi when a call comes in, allowing you to have a conversation on the closest device at hand.
With AT&T NumberSync, it's AT&T that's doing the call notification and routing; handy for when your iPhone is off, missing or without any battery life.