Freecall, a voice and data communications network serving mobile radio users in London, Manchester and Birmingham was inaugurated yesterday by National Mobile Radio Ltd. The Camberley-based company was formed in 1985 as a UKP3m joint venture between Motorola Inc, British Telecom and National Radio Ltd, when part of the Band III frequency spectrum previously used for TV broadcasting, was allocated by the department of Trade & Industry for mobile radio use. National Mobile Radio won licences to operate 20 channels in London, 19 channels in Birmingham, and 19 channels in the Manchester region and claims that each channel can operate up to 150 mobiles, bringing present capacity for the combined regions to just under 9,000 mobiles. The company describes its role as an airtime wholesaler, and claims that Freecall will provide small businesses with off-the-shelf mobile communications, at a price they can afford. As the name implies, once an installation and connection charge of around UKP90 has been paid, calls made within the system are free; users simply pay a monthly rental of UKP20 per mobile radio. The network infrastructure, designed by the UK arm of Storno Ltd, Copenhagen, uses Intel boards and microprocessors to form trunk systems controllers, or host computers, overseeing connections within each regional network. Features within the controller include a log-jam timer which balances traffic demand with available channels, a call-queueing facility which ensures that channels are always available unless the person being called is engaged, and an average connection time of five seconds. Currently, the network is seen as being of particular interest to companies within the distribution market: drivers can communicate with base and with other drivers without interference from outsiders speaking on the same channel. With data communications predicted to make a major impact within the next three to five years, National Mobile radio will be looking to expand its network capacity by 100% by 1993.