Covers the core DVB requirements to enable interactive services suppor ting broadcasting to the home with narrowband return channels. The sys tem defined in this ETS provides a generic solution for a variety of f uture interactive services, through the adoption of DSM-CC User-to-Use r, Download and Object Carousel protocols, as specified in MPEG2. The interactive services are provided on systems consisting of a high bitr ate downstream channel (up to the maximum bitrate of the Broadcast cha nnel) from the Service Providers to Service consumers and low bitrate interaction channels (up to 150 kbit/s). The Broadcast Service Provide r and the Interactive Service Provider need not operate from the same location. The services are primarily digital video broadcast enhanced with interactivity. At the simplest level the Interactive channel allo ws the consumer to react by voting, to order articles displayed in the broadcast programme, to select certain programme bouquets or to choos e movies in near-video-on-demand systems. It is also possible to deliv er text, graphics, audio and still pictures (including e-mail) on-dema nd , although this may require an interactive channel with higher bitr ates. There are many possible network configurations covering the currently specified DVB broadcast options including satellite, terrestrial, cabl e, SMATV and MMDS in conjunction with PSTN, ISDN, cable and other Inte ractive channel options. The network dependent protocols are specified in ETS 300 800/801 & ETS 300 803. The implications for interactive services via these types of networks are described in a separate guidelines document DTR/JTC-00DVB-44 Guid elines for the use of the DVB network-independent protocols for intera ctive services which will also summtrise the functionality of the pro tocols identified in this ETS.