IEC 60958-1:2004

IEC 60958-1
Edition 2.0 2004-03
INTERNATIONAL
STANDARD
Digital audio interface –
Part 1: General
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IEC 60958-1
Edition 2.0 2004-03
INTERNATIONAL
STANDARD
Digital audio interface –
Part 1: General
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
R
ICS 33.160.01 ISBN 2-8318-7427-0

– 2 – 60958-1  IEC:2004(E)
CONTENTS
FOREWORD.3

1 Scope.5

2 Normative references.5

3 Terms and definitions .5

4 Interface format.7

4.1 Structure of format.7

4.2 Channel coding.8
4.3 Preambles.9
4.4 Validity bit.10
5 Channel status.10
5.1 General.10
5.2 Applications.10
5.3 General assignment of the first and second channel status bits .11
5.4 Category code.11
6 User data.13
6.1 General.13
6.2 Applications.13
7 Electrical requirements.13

Annex A (informative) The use of the validity bit .14
Annex B (informative) Application documents and specifications.15
Annex C (informative) A relationship of IEC 60958 families.16
Annex D (informative) Transmission of CD data other than linear PCM audio.17

Bibliography .18

Table 1 – Preamble coding.9
Table 2 – Channel status data format .12
Table B.1 – Application documents and specifications .15

60958-1  IEC:2004(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
DIGITAL AUDIO INTERFACE –
Part 1: General
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 60958-1, edition 2 has been prepared by Technical Area 4, Digital system interfaces, of

IEC technical committee 100: Audio, video and multimedia systems and equipment.
This second edition of IEC 60958-1 cancels and replaces the first edition published in 1999 and
constitutes a technical revision.
All changes introduced in this second edition of IEC 60958-1 intend to clarify the structure and
the relationship between all of IEC 60958 series families.
A brief list of changes include:
• Annex B has been added to explain the definition given in 5.3 with relation of the families of
the IEC 60958 series. Clause 5.3 is also added to this description.
• Annex C has been added to explain the relationship of the IEC 60958 series families.
• Annex D has been added as an explanation for a data transmission other than linear PCM.
• Subclause 5.4 has been added to define category code appliance.
• A Bibliography has been added.

– 4 – 60958-1  IEC:2004(E)
The text of this standard is based on the following documents:

CDV Report on voting
100/552/CDV 100/755/RVC
Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

IEC 60958 consists of the following parts under the general title Digital audio interface:
Part 1: General
Part 3: Consumer applications
Part 4: Professional applications
The committee has decided that the contents of this publication will remain unchanged until
2006. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this standard may be issued at a later date.

60958-1  IEC:2004(E) – 5 –
DIGITAL AUDIO INTERFACE –
Part 1: General
1 Scope
This part of IEC 60958 describes a serial, uni-directional, self-clocking interface for the

interconnection of digital audio equipment for consumer and professional applications.
It specifies the basic structure of the interface. Separate documents define items specific to
particular applications.
The interface is primarily intended to carry monophonic or stereophonic programmes, encoded
using linear PCM and with a resolution of up to 24 bits per sample.
When used for other purposes, the interface is able to carry audio data coded other than as
linear PCM coded audio samples. Provision is also made to allow the interface to carry data
related to computer software or signals coded using non-linear PCM. The format specification
for these applications is not part of this standard.
The interface is intended for operation at audio sampling frequencies of 32 kHz and above.
Auxiliary information is transmitted along with the programme.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 60958-3, Digital audio Interface – Part 3: Consumer applications
IEC 60958-4, Digital audio Interface – Part 4: Professional applications
3 Terms and definitions
For the purpose of all parts of the IEC 60958 series, the following terms and definitions apply.
3.1
sampling frequency
frequency of the samples representing an audio signal
NOTE When more than one signal is transmitted through the same interface, the sampling frequencies are
identical.
3.2
audio sample word
value of a digital audio sample. Representation is linear in 2s complement binary form
NOTE Positive numbers correspond to positive analogue voltages at the input of the Analogue-to-Digital Converter
(ADC).
– 6 – 60958-1  IEC:2004(E)
3.3
auxiliary sample bit
one of the four least significant bits (LSBs) that can be assigned as auxiliary sample bits and

used for auxiliary information when the number of audio sample bits in the main data field is

less than or equal to 20
3.4
validity bit
bit indicating whether the main data field bits in the sub-frame (time slots 4 to 27 or 8 to 27,

depending on the audio word length as described in 4.1.1) are reliable or not

3.5
channel status
carrier, in a fixed format, of information associated with each main data field channel which is
decodable by any interface user
NOTE Examples of information to be carried in the channel status are: length of audio sample words, pre-
emphasis, sampling frequency, time codes, alphanumeric source and destination codes.
3.6
user data
data channel provided to carry any other information
3.7
parity bit
bit provided to permit the detection of an odd number of errors resulting from malfunctions in
the interface
3.8
preamble
specific patterns used for synchronization
NOTE There are three different preambles (see 4.3).
3.9
sub-frame
fixed structure used to carry information (see 4.1.1 and 4.1.2)
3.10
frame
sequence of two successive and associated sub-frames
3.11
block
group of 192 consecutive frames
NOTE The start of a block is designated by a special sub-frame preamble (see 4.3).
3.12
channel coding
coding method by which the binary digits are represented for transmission through the int
...