EN 50221:1997

A set of standards has been designed to be used in digital video broadcasting. These standards include source coding, channel coding, service information and decoder interfaces. In addition, a conditional access system is used when there is a need to control access to a broadcast service. It has been decided that the conditional access system need not be standardized, although a common scrambling algorithm is provided. It remains for broadcasters to access decoders with different conditional access systems and to ensure that they have choice of supply of such systems. A solution is to use the common scrambling algorithm and to execute solutions for access based on commercial agreements between opera-tors. This solution can operate with single CA systems embedded in decoders. A second solution is based on a standardized interface between a module and a host where CA and more generally defined proprietary functions may be implemented in the module. This solution also allows broadcasters to use modules con-tainting solutions from different suppliers in the same broadcast system, thus increasing their choice and anti-piracy options. The scope of this document is to describe this common interface. The decoder, referred to in this specification as the host, includes those functions that are necessary to receive MPEG-2 video, audio and data in the clear. This specification defines the interface between the host and the scrambling and CA applications, which will operate on an external module