This Recommendation constitutes a common standard for a conditional access system for long-distance international transmission of digital television according to Recommendation J.811). It first gives an overview of any conditional access system, describing the categories of conditional access messages which need to be transmitted. It specifies a transport protocol based on HDLC frames for the conditional access messages sent in channel CA1 of Recommendation J.81.
Furthermore, an architecture of the whole transmission system, including the conditional access features, is described. This architecture differs from the traditional pay-TV systems architecture in the way that it stresses the need for an access control authority which is not co-sited with the transmitters.
The main conditional access equipments and interfaces needed to operate the conditional access system are also modelled. Their functionalities are described and some implementations are proposed, depending on the application. Lastly, practical implementations are also provided depending on the level of security and functionality required by the application.