It works like this: once you connect your smartphone to WiFi, EE immediately hands off communication from its voice network to the broadband provider. Incoming/outgoing calls or texts are then broken down into packet data and routed back to EE's core network, completing the circuit. Because EE utilises tech (IP Multimedia Subsystem or IMS if you're interested) already supported by many of the latest smartphones, calls are automatically encrypted and can't be eavesdropped upon by a public WiFi provider. You won't need to launch an app or tweak settings on your phone either, as calls can be made through the phone's native dialler and will be deducted from your allowance accordingly.
Three, on the other hand, plans to do things a little differently. In "early August," the operator will launch Three inTouch, which operates much in the same way as EE (offering calls and texts over a WiFi connection). However, like O2's TU Go, Three's service requires the use of an app.
EE also revealed that it'll soon start enabling VoLTE services, expanding its high-definition voice service across its networks and extending coverage to rural areas that had previously been unconnected. In regards to its WiFi plans, EE tells us that it has already tested the service on a Samsung Note 3, which was enabled by a simple over-the-air firmware upgrade sent by the carrier. Ahead of its autumn launch, the provider says it intends to test "hundreds" of public WiFi services to ensure they are capable of delivering "high-quality" calls. If they are unable to, EE says it will simply not allow customers to use them.