COMPATIBLE TRANSMISSION AND RECEPTION OF OPERATIONAL SIGNALS TO BE PROCESSED BY A RECEIVER

摘要

The invention addresses the problem of backwards compatibility and future proofness of data transmission systems and, more particularly, interactive television broadcast transmissions. In view hereof, service providers must take into account that their service is to be processed by receivers having different capabilities. To this end, operational signals for different receiver types are identified by respective level data (operation_level) defining which receiver capabilities are required to perform the operation. Two operation levels (full_operation_level and minimum_operation_level) are sufficient. More levels can be defined by means of chaining techniques. In a practical embodiment, a plurality of operations is packed in a transmission block. Events (e.g. user actions) are represented by an index to said list, the index depending on whether the receiver has full or minimal capabilities.