IEC 60958-1:2021

Overview

IEC 60958-1:2021 - Digital audio interface, Part 1: General - defines the basic structure of a serial, uni-directional, self‑clocking digital audio interface used for interconnecting consumer and professional audio equipment. The standard is primarily intended to carry monophonic or stereophonic programmes encoded as linear PCM (up to 24 bits per sample) at audio sampling frequencies of 32 kHz and above, but it also supports transmission of non‑linear PCM and other coded data (e.g., multimedia or software‑related data). This fourth edition (2021) replaces the 2008 edition and Amendment 1:2014 and includes technical revisions, notably support for relevant parts of IEC 60958‑5.

Key topics and technical requirements

• Interface format: Defines the serial frame and sub‑frame structure, preambles, and channel coding for carrying audio words and auxiliary information.
• Channel coding and validity: Specifies how audio sample words are formatted, includes the validity bit to indicate sample integrity, and preamble patterns to mark frame boundaries.
• Channel status and user data: Provides a structured channel status block and user data fields to carry metadata, category codes, and application flags alongside audio content.
• Electrical and optical requirements: Covers physical transmission media requirements for both unbalanced electrical interfaces and optical links, including timing accuracy, jitter considerations, and connector configuration guidance.
• Applications and annexes: Informative annexes describe use of the validity bit, application documents, relationships within the IEC 60958 series, transmission of non‑linear data, and optical link characteristics.
• Scope limits: The document provides the general format; application‑specific details are defined in separate parts of the series.

Applications and who uses it

IEC 60958‑1 is essential for:

• Audio equipment manufacturers designing digital outputs/inputs for consumer and professional products.
• System integrators and AV engineers implementing reliable digital audio links between sources, processors, and receivers.
• Test and compliance labs verifying conformance to digital audio interface specifications.
• Typical uses include digital interconnection for playback and recording equipment, digital mixers, AV receivers, set‑top devices and other systems requiring standardized PCM or coded audio streams.

Related standards

• IEC 60958 (series) - other parts covering consumer (IEC 60958‑3), professional (IEC 60958‑4) and enhancements (IEC 60958‑5)
• IEC 60268‑11 - connectors for sound system interconnection
• IEC 60874‑17 - fibre‑optic connector specifications

Keywords: IEC 60958-1, digital audio interface, linear PCM, 24‑bit audio, channel status, user data, optical and electrical requirements, audio sampling frequency.