EE's new 'smart number' tech means you can make a call even when you don't have your phone or it has run out of battery.
While the primary device needs to be on EE, the others don't need to be - the system uses the now-familiar Wi-Fi Calling tech. EE says the data used by the service through another network or on Wi-Fi is minimal, around 10MB for a 30-minute call.
Multiple calls can also be made at the same time on different devices which is rather clever, though as you'd expect the calls will still come out of your minutes allowance if they're using your number.
You're also able to 'hand off' calls to other devices - this uses Apple's Handoff tech based around devices linked to your iCloud account so you can pick up the call via the app switcher on the device you want to move the call to.
To get started, you'll need to be on a EE pay monthly plan on your iPhone and have iOS 11.3 on an iPhone 6 or later. iPads will need to be on iOS 10 (or later) and OS X El Capitan or later is required for Macs.
EE Smart number will arrive on Android devices in the future, although EE has given no indication of the timescale in question.
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