Abstract
The Heinrich-Hertz-Institute in 1975 received the assignment to develop an experimental interactive broadband communication system for 10000 subscribers, called VBD (Vielteilnehmer-Breitband-Dialog system). Apart from more TV and radio programs, the subscriber has the opportunity to obtain interactively random-access information from a central computer. This information might be film and soundtracks (distributed by an individual broadband-channel) or, by a narrowband-channel, data for text or graphics displays. These data are used for the generation of the video-signal in the user terminal.