BT's converged fixed/mobile phone service -- called Bluephone during development -- has been launched. BT Fusion, as it is now known, operates as a mobile phone outside the house, and uses a Bluetooth base station within the house, to switch calls over a BT Broadband link.

Future plans include a fashionable Motorola RAZR handset, instead of the current v560 handset, and Wi-Fi support within the year. The basics of Bluephone have been well known for some time, but the launch filled in details of pricing, and the future roadmap.

One limitation that cropped up is the fact that it is only available to BT Broadband subscribers. This is for commercial reasons, as there is no technical reason why those with other broadband providers couldn't be connected.

For £9.99 (AU$23.7) a month, users get a mobile with 100 free minutes, which can be used in the house for BT's normal landline rates. For £14.99, users will get 200 free minutes. Outgoing calls to landlines are the same as with a BT landline, but calls to mobiles, and all incoming calls, are charged at mobile rates. Each call is billed at the rate on which it started, instead of per-minute, so it may pay to start a long call before leaving the house.

Secondary subscribers pay £9.99 for another handset, and share the same free minutes package. Up to three handsets can use the service at any time, and the subscriber's landline is also always available. Fusion handsets can also be used on a friend's hub, once a PIN number is entered: "We can see this becoming an ecosystem," said Steve Andrews, group chief of mobility and convergence at BT.

The current version of Fusion is aimed at consumers, not business, but only 400 will be sold until the full roll-out in September, when Fusion will be sold to BT broadband subscribers. The price includes a free handset and Bluetooth hub - which also includes a router and a Wi-Fi base station.

"It's just a start," said Andrews. "There's built in Wi-Fi [in the hub], which lays the foundation for future services." With Wi-Fi already in the hub, a Wi-Fi version (which we found out about earlier this year) would only need decent handsets, which are coming from Nokia by the end of the year. Future services on Fusion will include converged voice and email messaging, as well as IM support.

The Wi-Fi version could be made to roam to BT's Openzone hotspots, and eventually to guest WLANs in offices. Andrews promised a business-friendly Enterprise Fusion service, but gave few details, although it appears Enterprise Fusion may not use UMA, the standard that builds Wi-Fi and Bluetooth into mobile phone services, but does not open up the full Internet to users (read Limping mobile standard gets Wi-Fi pick-me-up).

"They're obviously ditching UMA," said analyst Dean Bubley of Disruptive Analysis. "The business service will be based on an Internet-connected IP PBX."

"Fusion is quite a good brand name for a converged service," said Bubley. "I imagine all the world's operators are currently busy thumbing through their thesauruses, but BT's got the first pick."