Ntl is offering London-based computer users the chance to take part in a free trial of a wireless broadband network, but is insisting that there's little chance of a commercial service coming soon. The company has posted a request on its Web site looking for people to sign up for the trial. Ntl is planning to offer data transfer rates of 512kbps downstream and 128kbps upstream -- similar speeds to BT's consumer ADSL package. Users will get free use of the network until 15 November, in return for giving feedback about the service. The trial will only be available to people who live in or near Gunnesbury, Wandsworth, Guy's Hospital, Shooter's Hill and Croydon -- because ntl will only be using four transmitters in the trial. Ntl was keen to play down the significance of the trial, and insisted that it would not be launching a commercial wireless broadband service anytime this year. "It's really early days," a spokesman explained to ZDNet on Monday, adding that such a service was "only an option" for the future. According to details on ntl's Web site, testers might be given the chance to carry on using the service after 15 November. Some reports have claimed that the service is likely to retail at £25 per month, but according to ntl £35 is a more likely price. Ntl is primarily known for its cable division, which has recently begun selling a cable modem service for £24.99 a month. It also has a keen interest in the mobile phone industry. It was unsuccessful in its attempts to win a 3G licence in last year's auction, but recently signed a £150m contract with Orange to work on "next-generation" mobile technology. The company is also thought to own around 2000 mobile phone transmitting towers across the country, which are currently used by mobile network operators. It is possible that ntl is considering a way of attaching equipment to these towers to create a high-speed wireless network. Ntl is certainly pleased with its broadband cable product. According to latest figures it has sold at least 52,000, following a high-profile advertising campaign. See the Broadband News Section for the latest on cable modems, ADSL, satellite and other high-speed access technologies. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Telecoms forum. Let the editors know what you think in the Mailroom. And read other letters.