The A to Z of wireless

D is for Dual-mode phones

Dual mode smartphones are those which include a wi-fi chipset as well as a cellular radio. Such devices enable mobile users to get fast and potentially cheap internet access via wi-fi hotspots and/or home wi-fi routers.

Analyst In-Stat says 56 million cellular-wi-fi phones units were shipped in 2008 - an increase of 52 per cent on the year before.

The increase in dual-mode phones opens up the possibility of fixed-mobile convergence (FMC) - where one phone can be used to make calls over both cellular and fixed broadband networks, switching between the two where necessary. Voice calls can be routed over broadband using VoIP when in range of a wi-fi hotspot - enabling FMC users to cut call costs.

Supermarket giant Tesco has already caught on to the trend, inking a £100m network overhaul deal last year. The deal, with C&W, includes FMC and the retailer hopes it will save £10m per year.

C&W is not the only telco pushing the technology. An early attempt by BT to interest the consumer market in a dual mode wi-fi handset - marketed under the Fusion brand - was not an overwhelming success.

A business version of the service proved more popular however and analysts predict business use of dual mode handsets will rise as companies converge fixed and mobile communications to cut costs.

Cost is not the only selling point of FMC: it can also help improve reception. 3G signals can often be lower quality indoors, where wi-fi thrives, so in mobile blackspots dual-mode users need not be without coverage.