From Digital Interface Handbook, Third Edition

4.2 Background to Internationally Standardized Interfaces

Within the audio field the Audio Engineering Society (AES) has been a lead body in determining digital interconnect standards. Although the AES is a professional society, and not a standards body as such, its recommendations first published in the AES3-1985 document1 have formed the basis for many international standards documents concerning a two-channel digital audio interface. The Society has been instrumental in coordinating professional equipment manufacturers' views on interface standards although it has tended to ignore consumer applications to some extent, preferring to leave those to the IEC (see below). A consumer interface was initially developed by Sony and Philips, subsequently to be standardized by the IEC and EIAJ, and as a result there are many things in common between the professional and consumer implementations. Before setting out to describe the international standard two-channel interface it is important to give a summary of the history of the standard, since it will then be realized how difficult it is to call this interface by one definitive title.

Other organizations that based standards on AES3 recommendations were the American National Standards Institute (ANSI), the European Broadcasting Union (EBU), the International Radio Consultative Committee (CCIR) (now the ITU-R), the International Electrotechnical Commission (IEC), the Electronic Industries Association of Japan (EIAJ) and the British Standards Institute (BSI). Each of these organizations formulated a document describing a standard for a two-channel digital audio interface, and although these documents were all very similar there were often also either subtle or...

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Topics of Interest

4.3 Standard Two-Channel Interface Principles Common to all the international standards for a two-channel interface is the data format of the subframe containing samples of audio data for each...

Overview For the purposes of this book, digital audio interfaces will be divided into two types. This chapter is concerned with those that are dedicated point-to-point audio interfaces (e.g.

4.7 The User (U) Channel The U bit of each subframe has a multiplicity of uses, many of which have remained hidden from the user of commercial equipment, such as the carrying of text, subcode, and...

4.4 Sampling Rate Related to Data Rate The standard two-channel interface was originally designed to accommodate digital audio signals with sampling rates between 32 and 48 kHz, with a margin of...

4.9 Data-Reduced Audio Over Standard Two-Channel Interfaces 4.9.1 General Principles The standard two-channel interface was originally designed for linear PCM audio samples but in recent years there...