Ofcom, the UK communications regulator, has issued a consultation on the interpretation of the 10% data limit which restricts non-television services on the digital terrestrial television platform in the UK.

There are currently six digital terrestrial television or DTT multiplexes in the UK, one of which was originally granted by the government to the BBC, with the other five licensed by Ofcom.

The legislation relating to those multiplexes licensed by Ofcom reserves at least 90% of the capacity on each of the multiplexes for specific types of programme services, intended to ensure that the capacity is used for television, rather than other communications purposes.

The programme services include conventional television channels, including subtitling, audio description, promotions and listings material such as EPG data, relevant technical services such as encryption, and other services directly related to a programme such as interactive applications.

Not included within the 90% provision are the public teletext service, interactive services which are not directly related to a programme or its promotion, such as games, or any service which consists exclusively of advertising.

The recent success of digital terrestrial television, branded as Freeview, has given rise to a high level of demand for capacity, where even modest data rates can command a high value.

With the latest MHEG-5 1.06 software standard being supported by receivers and transmitted over the air to update existing set-top boxes, Ofcom says broadcasters will be increasingly confident in the stability of the platform and the range of features available for them to use interactive services.

“It is probable that there will be an increased level of demand for data services on DTT multiplexes, thus increasing the need for clarity about what capacity can be used for this purpose,” observes Ofcom.

The regulator is therefore seeking industry feedback on draft guidance on how the existing regulations should be interpreted in a consultation on ‘Data limits on digital terrestrial television multiplexes’. The closing date for responses is 14 September 2006.