"This ETS covers the core Digital Video Broadcasting (DVB) requirements to enable interactive services supporting broadcasting to the home with narrowband return channels (see annex A: Bibliography - ""DVB commercial requirements""). The system defined in this ETS provides a generic solution for a variety of future interactive services@ through the adoption of DSM-CC User-to-User@ Download and Object Carousel protocols@ as specified in TR 101 194 [2]. The interactive services are provided on systems consisting of a high bitrate downstream channel (up to the maximum bitrate of the Broadcast channel) from the Service Providers to Service consumers and low bitrate interaction channels (up to 150 kbit/s). The Broadcast Service Provider 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 allows the consumer to react by voting@ to order articles displayed in the broadcast programme@ to select certain programme bouquets or to choose movies in near-video-on-demand systems. It is also possible to deliver text@ graphics@ audio and still pictures (including e-mail) on-demand@ although this may require an interactive channel with higher bitrates. There are many possible network configurations covering the currently specified DVB broadcast options including satellite@ terrestrial@ cable@ SMATV and MMDS in conjunction with PSTN@ ISDN@ cable and other Interactive channel options. The network dependent protocols are specified in ETS 300 800 [3]@ ETS 300 801 [4]@ ETS 300 803 [5]. The implications for interactive services via these types of networks will be described in a separate guidelines document TR 101 194 [2] which will also summarize the functionality of the protocols identified in this ETS."