06571392 is referenced by 185 patents.
In interactive television, information from an information resource may be displayed along with television video in a synchronized fashion. When information is to be displayed at a point in the television video, a Uniform Resource Identifier (URI) that identifies the information resource is broadcast along with the television video on a one-way broadcast communication channel. A receiver unit receives the URI from the broadcast channel. If the information resource identified by the URI is available locally (for example, is present in local storage on the receiver unit), then the receiver unit uses the URI to retrieve the information resource locally. If, on the other hand, the information resource is not available locally, then the receiver unit uses the URI to retrieve the information resource from the Internet. The information resource can therefore be received from a high speed source (for example, from VBI lines
) if such reception is possible, but if such reception is not possible then the information resource can be retrieved. from another source (for example, from the Internet). Once the receiver unit has retrieved the information resource, the receiver unit can display the information along with the television video.