BT has launched what it calls a "ground breaking" fixed-mobile communications service for businesses.

BT Corporate Fusion combines WiFi and mobile phone service for voice calls, using VoIP when calls are made over a wireless network, lowering costs. The service will be rolled out initially in the UK and Italy early next year, with Germany, France and Spain to follow. Handset deals will be announced in the coming weeks.

Under the new service, calls made from dual-mode WiFi-GSM phones within an office building are connected through access points and routed over the existing fixed-line infrastructure. Outside the building, the dual-mode phone operates like a mobile phone, providing ubiquitous coverage and global roaming. These calls, however, are more expensive because they are carried over mobile phone networks.

Several operators, including Deutsche Telekom and the Danish subsidiary of Sweden's TeliaSonera, have launched new converged fixed-mobile services but have been targeted at consumers, largely in a move to keep customers from abandoning traditional fixed-line telephone service.