O2 has outlined its plans for a UK launch of the hugely popular Japanese mobile phone technology i-Mode, which allows customers to buy content and services via their phone bill or pre-pay balance.

In Japan, that means downloading ringtones, games, cartoons and music, trading shares, buying tickets and subscribing to premium information services. Due to launch in time for Christmas this year, i-Mode will be O2's answer to the likes of Vodafone Live.

According to Jag Minhas, O2's chief i-Mode architect, the system's main advantages over WAP-based data services are consistency and ease of use. Every handset will have the same basic applications, and the i-Mode main menus will be stored on the handset to save connection time.

"The technologies are not proprietary, but the processes are tightly specified and geared to giving a good customer experience," he said. "We are trying to avoid the scattergun approach we had with WAP settings." The aim is to make data services as simple to use as voice, Minhas added.

A big advantage of i-Mode is that it uses a derivative of HTML – formerly cHTML but now XHTML – making it relatively easy to repurpose an existing website, with the handset resizing images and pages as needed. It also relies heavily on Java, in NTT DoCoMo's DoJa variant, and some handsets will support Macromedia Flash.

However, there could be compatibility problems, as i-Mode operates differently to other mobile data services, warned Paul Danter, solutions head at mobile services developer Argogroup. "With other i-Mode operators there isn't necessarily interoperability between ordinary MMS and i-Mode MMS. i-Mode is very email-centric," he said. "Plus it doesn't remove the need to develop your service in other formats for other operators."

Another challenge for O2 is that i-Mode requires all-new handsets, and because the menus are pre-loaded, those handsets can only be used on O2. Minhas says all the major manufacturers are developing i-Mode devices, but O2 will still need to get them into users' hands.

Several other European networks are already offering i-Mode services, including Bouygues in France, E-Plus in Germany and Wind in Italy, and they say that on average monthly revenue per user has risen by 6 euros (£4) to 10 euros (£6.70). O2 has exclusive rights to i-Mode in the UK and Ireland. Its German operation will use the technology, but under a different name.

Content providers will need to sign up with O2. They will then receive the bulk of the fees paid by the customer, the company claims. O2 will charge a commission, plus fees for the GPRS traffic consumed. O2 is acknowledging that its strengths lie not in content provision, but in delivering data and using its relationship with the customer to provide billing capabilities.

Minhas says there are opportunities for business use, too: either business-to-business sales, or for a company to enable its intranet for i-Mode access. The service will also provide email to the phone with push notification of new messages, although not access to web-based email accounts.