ITU-T J.182 PDF

This Recommendation defines the characteristics of the interface between television set-top boxes and television presentation devices in the home, when such signals are provided in analogue component video form carried on three parallel channels for 60 Hz display.

This Recommendation recognizes that television users in the home are likely to access television programmes, sound-broadcast programmes and other additional services from a variety of service providers that use a variety of delivery systems.

For instance, a television user may access television programmes and sound programmes from a cable television network to which he is connected, from terrestrial broadcasting, from satellite broadcasting, from recorded material such as videocassettes, DVDs and CDs, or even from the Internet.

Such programmes may be received in digital form or in analogue form, and they may be open, or may be subject to conditional access.

Reception and presentation of this host of programmes in different formats require the use of a variety of demodulators and decoders. Such devices could be integrated into the home television receiver, but this condition is sometimes not viable due to constraints imposed by the marketplace. The present situation is that signals received on different delivery systems are often processed in different, dedicated "set-top boxes" which provide outputs to the television and sound displays in a form that a normal television or sound display can understand, e.g. as analogue component or analogue composite signals.