EE's WiFi Calling service is now available on a raft of top end smartphones, including the iPhone 6 and iPhone 6 Plus and new Samsung Galaxy S6 models.
The service means that those in signal not-spots, such as remote areas, basement flats or even on the London Underground, can still make phone calls and send and receive messages as normal when connected to a WiFi hotspot.
It works natively from the phone's dialler and contacts book and does not require an app to be used by the sender or receiver. There is no cost involved.
Apple iPhone 6, iPhone 6 Plus and iPhone 5S and 5C owners can now access the service by installing the iOS 8.3 update while owners of the brand new Samsung Galaxy S6 and S6 Edge, which went on sale on 10 April, can also use the service.
The other device that can already use the service is Microsoft's mid-tier Lumia 640 phone.
EE said that it expects as many as five million people to be able to use the service by the middle of the year, as phone companies issue software updates containing the necessary functionality.
The move could well be of huge benefit for homes and offices that suffer poor mobile coverage. Even those in urban areas are often affected by poor indoor coverage that can make mobile calls patchy and prone to failing.
EE chief executive Olaf Swantee explained that the firm hoped to do away with these frustrations with the new service.
“Losing coverage at home is a major frustration, and WiFi Calling will make a real difference to millions of customers across the UK, from basement flats in London to the most rural homes in the country,” he said.
“Our customers want to be able to call and text no matter where they are, and they don’t want to have to think about which app they need to use or if their friends have a particular third-party service.”
WiFi Calling will be available to EE pay monthly consumer and small business customers with compatible devices from Friday, while corporate 4GEE customers can begin using the service from the summer.
The company also confirmed that it was working on Voice over LTE services which would improve call quality, but no further update on this work has been revealed.
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