scope:

Introduction

Many countries are now broadcasting information and other services in a television channel, in addition to normal television services. Most or these use digital data broadcasting, and probably the most widely-known at the present time are the teletext systems described in Annex I to Recommendation 653. Systems which use analogue techniques, or a combination of digital and analogue techniques, are also within the scope of this report.

A classification of additional services is given in Table I, which, for completeness, also includes services using sound-broadcasting channels.

The sections of this report are as follows:

- section 2 deals with multiplexing and organizational methods for data broadcasting;

- section 3 deals with the services which use data broadcasting systems;

- section 4 deals with systems to provide conditional access to services;

- section 5 is concerned with still-picture television broadcasting (SPTV).