Free-to-air broadcaster Asia Television (ATV) is providing select viewers with free smart boxes which offer basic interactive services, to lure viewers away from dominant Television Broadcasts (TVB). ATV is distributing simple set-top boxes to 400 households, which will be able to access basic interactive services attached to television programmes on ATV's Home and World channels. The upgraded technology is transmitted in Vertical Blanking Intervals, which is part of the terrestrial broadcasting frequency. The viewers will be able to access additional content in eight programme categories. The content will mainly be in the form of text. For example, a viewer watching a news broadcast will be able to minimise the screen and read the text of the broadcast instead. Kwong Hoi-ying, senior vice-president of programming, said the trial would run until July. Next month the broadcaster hopes to secure a Public Non-Exclusive Telecommunications Service (PNETS) licence, which would allow it to offer its smart box services to all viewers. The HK$500 smart boxes are made in Hong Kong. Mr Kwong said he did not expect the interactive services to earn any revenue. He said the boxes were being introduced to expand ATV's viewership. 'The improvement in ratings would mean more advertising dollars,' he said. Last week, ATV Home channel attracted on average about 12 per cent of prime-time viewers, while TVB Jade claimed 88 per cent - the highest since the adoption of a viewership monitoring system. Yesterday, the Television and Entertainment Licensing Authority (Tela) warned broadcasters that the technology must be offered freely under the broadcaster's domestic free-to-air licence. Tela commissioner Eddy Chan Yuk-tak said the broadcaster and its affiliates had guaranteed the free services and the authority would not permit the service to be turned into a back-door pay-television service.