This Recommendation specifies data services to be used for digital television broadcasting. The ITU Radiocommunication Assembly considering: a) that digital television broadcasting has been introduced in many countries around the world; b) that an efficient service identification mechanism is essential due to the flexible and complex nature of the service; c) that conventional television broadcasting systems already provide means to convey ancillary data; d) that subtitling is an important service in an increasing number of countries; e) that various multimedia services in other media is expected to stimulate the interest for a broadcast multimedia service; f) that such a service may give broadcasters opportunities to provide completely new services as well as promoting existing services; g) that commonality of identification of different data services is desirable recommends.