Optus has become the first Australian carrier to make the jump: it's launched a WiFi calling app to let users make calls when they can't get a 3G/4G signal.
The company has launched its snappily-named WiFi Talk app, which like Skype lets users have conversations and send text messages over a handy wireless LAN connection.
Unlike an over-the-top (OTT) voice-over-internet-protocol connection, WiFi Talk calls will be billed to the user's mobile service. On the upside, you can talk to any phone number on your plan rate without buying SkypeOut credits, you can send texts to any mobile, and you can receive calls without having to buy a SkypeIn number.
WiFi Talk is available for Android (version 4.0 and above) or iOS, but not (yet) for Windows or Blackberry. Optus recommends a 100 Kbps connection speed for the app. ®
+Comment: Mobile operators have many reasons for deciding to pursue WiFi calling.
Their networks are expensive to operate and not getting cheaper: upgrading to 4G is an ongoing drain on the capex budget even without trying to fill in every single gap in coverage, so WiFi offload is attractive from that point of view.
But the OTT threat posed by Skype – and Hangouts, Facetime, WhatsApp and so on – can't be ignored. The one thing that a boring telephone call (or SMS for that matter) has over OTTs is true any-to-any connectivity.
The OTTs haven't gone back to look at the history of SMS – or re-read Metcalfe's Law – and treat their apps as a walled garden.
Which is just fine by the mobile operators, since it protects their networks from becoming dumb bit-pipes. For now. ®