December 2025: New Standards Advance Telecommunications, Audio & Video Engineering

Stay informed with the latest developments in Telecommunications, Audio and Video Engineering standards. December 2025 marks a pivotal month with five important international standards published, covering fibre optic sensor measurements, FM receiver testing, and high-performance RF connector specifications. These updates directly impact engineering quality, compliance, and competitiveness across broadcast, network, and audio-visual technology sectors.

Overview

Telecommunications and audio/video engineering underpin global connectivity, broadcasting, and media infrastructures. As systems become more complex and performance-driven, internationally harmonized standards are essential to ensure interoperability, measurement accuracy, safety, and product reliability. This article—Part 2 of a comprehensive seven-part series—delivers a close look at five newly published standards from December 2025, unpacking their scope, technical requirements, and practical implications.

Whether you are an engineer, quality manager, procurement specialist, or compliance officer, understanding these standards is critical for:

• Maintaining conformance and certification
• Optimizing product performance
• Streamlining integration and procurement decisions
• Mitigating regulatory and contractual risks

Read on to discover the essential highlights and actionable guidance on each standard, with direct links to the authoritative documents on iTeh Standards.

Detailed Standards Coverage

IEC 61757-1-4:2025 – Distributed Fibre Optic Strain Sensing Based on Rayleigh Scattering

Fibre optic sensors — Part 1-4: Strain measurement — Distributed sensing based on Rayleigh scattering

Released in December 2025, IEC 61757-1-4:2025 establishes a unified framework for measuring absolute strain along single-mode optical fibres using Rayleigh backscattering analysis. This advanced distributed sensing approach enables spatially resolved strain measurements over distances ranging from 10 meters up to tens of kilometers—a critical capability for infrastructure monitoring, civil engineering, energy, and transport applications.

Scope & Key Requirements:

• Defines terminology, structures, and measurement methods specifically for distributed fibre optic strain sensors leveraging Rayleigh scattering (not for point or dynamic strain measurements).
• Addresses both pure Rayleigh and hybrid Brillouin-Rayleigh systems for enhanced measurement quality.
• Specifies essential performance parameters: strain error, spatial resolution, repeatability, uncertainty, warm-up time, and system performance under attenuated or high-loss conditions.
• Details standardized measurement procedures to ensure reproducibility and comparability.

Who Should Comply:

• Manufacturers, integrators, and users of fibre optic monitoring systems (energy, civil, railways, structures, geotechnical).
• Quality assurance and calibration labs working with distributed sensing devices.

Practical Implications:

• Ensures robust, field-ready strain measurements for distributed infrastructure monitoring.
• Supports regulatory certification, technical audits, and customer acceptance.

Key highlights:

• Standardizes distributed fibre optic strain sensor terminology and test methods
• Enables absolute strain measurement across extended distances
• Covers hybrid systems leveraging both Brillouin and Rayleigh effects

Access the full standard:View IEC 61757-1-4:2025 on iTeh Standards

IEC 60315-4:1997 – Methods of Measurement on FM Sound Broadcasting Receivers

Methods of measurement on radio receivers for various classes of emission — Part 4: Receivers for frequency-modulated sound broadcasting emissions

This updated edition of IEC 60315-4:1997 (consolidated with Amendment 1 as of December 2025) delivers the international baseline for measuring the performance of FM sound broadcasting receivers and tuners. Its guidance is instrumental for ensuring reliable, consistent audio quality in radio receivers globally.

Scope & Key Requirements:

• Applies to receivers/tuners for frequency-modulated (FM) audio broadcasting, suitable for deviations of ±75 kHz/±50 kHz in ITU Band 8.
• Covers RF signal-based testing at the antenna terminal—focusing on sensitivity, noise, selectivity, unwanted signal rejection, and audio output fidelity.
• Addresses measurement procedures for issues such as signal-to-noise ratio, capture ratio, rejection of adjacent/intermediate channels, harmonic and intermodulation distortion, crosstalk, and audio-frequency characteristics.

Who Should Comply:

• Radio receiver and tuner manufacturers and suppliers
• Test laboratories and compliance bodies
• Broadcasters, network integrators, and OEMs requiring certified receiver performance

Practical Implications:

• Assurance of compliant receiver performance for international markets
• Control over radio selectivity, audio quality, and interference rejection

Key highlights:

• Comprehensive, repeatable test procedures for FM receiver classes
• Measures signal handling, sensitivity, dynamic range, and distortion
• Strong focus on realistic broadcast signal environments

Access the full standard:View IEC 60315-4:1997 on iTeh Standards

EN IEC 61169-74:2025 – HN Series RF Coaxial Connectors with Screw Coupling

Radio-frequency connectors — Part 74: Sectional specification for HN series RF coaxial connectors with screw coupling — Characteristic impedance 50 Ω

EN IEC 61169-74:2025 introduces a dedicated specification for HN series RF connectors, widely used in demanding microwave transmission systems. This standard bridges detail specification requirements with comprehensive test and quality assessment schedules, ensuring high interoperability and system resilience for RF components.

Scope & Key Requirements:

• Defines dimensional and performance requirements for HN series screw coupling RF connectors with 50 Ω impedance (grade 2 high-performance, grade 0 standard test options).
• Lays out mating face geometry, gauge and test connector requirements, and comprehensive mechanical/electrical test schedules per IEC 61169-1.
• Endorses recommended climatic categories, acceptance/periodic test routines, and procedures for preparing compliant detail specifications.
• Suitable for operating frequencies up to 6 GHz and compatibility with a wide spectrum of RF cables and microstrips.

Who Should Comply:

• RF connector and cable manufacturers, system integrators, and testing houses
• Industries deploying high-reliability microwave transmission (defense, broadcasting, telecom backbones)
• Procurement and quality management professionals overseeing RF hardware selection

Practical Implications:

• Guarantees connector interoperability, reliability, and ease of qualification across multiple suppliers
• Enables streamlined acceptance and periodic quality inspections

Key highlights:

• Defines interface, test, and quality requirements for HN RF connectors
• Supports frequency operation up to 6 GHz for advanced telecom applications
• Standardizes connector dimensions for robust, high-performance system design

Access the full standard:View EN IEC 61169-74:2025 on iTeh Standards

Industry Impact & Compliance

Implementing up-to-date standards is vital for:

• Reducing technical and operational risks: Updated measurement and interoperability guidelines identify potential system defects, ensuring consistent performance across devices and installations.
• Streamlining compliance and certification: Adherence to new international standards simplifies product approvals, regulatory filings, and contract negotiations.
• Supporting market access and customer trust: Buyers and users look for standards-compliant solutions—particularly in regulated or critical infrastructure sectors.

Compliance Timelines & Transition Guidance:

• Be proactive: Integrate these standards into procurement specifications, design cycles, and internal test protocols as soon as possible after publication.
• For legacy products, assess gaps and develop a phased compliance roadmap; consider re-certification if needed for critical contracts.
• Engage accredited labs for third-party verification against these updated specifications.

Risks of non-compliance include:

• Delayed market entry, failed certifications, or contractual penalties
• Reputational or financial damage from system failures or performance shortfalls

Benefits of adoption:

• Higher product quality and customer satisfaction
• Improved system interoperability and longevity
• Accelerated deployment in emerging markets and advanced applications

Technical Insights

Common Technical Requirements

• Measurement repeatability and uncertainty control: All five standards emphasize the need for repeatable, auditable measurement protocols—whether for strain sensing, signal reception, or connector quality.
• Environmental robustness: Specifications for RF connectors and sensors cover a wide range of climatic conditions, ensuring field reliability.
• Signal integrity and interference management: FM receiver and connector standards especially focus on maintaining signal integrity through rigorous testing for noise, distortion, crosstalk, and unwanted interference.

Implementation Best Practices

1. Document Baseline Performance: Benchmark current systems against new standard specifications; record and track all measurement/calibration procedures.
2. Engineer for Interoperability: Use the dimensional and interface requirements in connector standards to guarantee future hardware compatibility.
3. Perform Regular Testing: Establish periodic test schedules for critical parameters such as attenuation, impedance, or response accuracy—leverage test connector definitions and external audit services.
4. Embrace Hybrid Technologies: Hybrid sensing systems or multi-standard compliance can provide enhanced measurement accuracy and redundancy.

Testing and Certification Considerations

• Work with accredited labs experienced in telecommunications and audio/video metrology.
• Maintain detailed calibration records compliant with ISO/IEC Guides referenced by these standards.
• Align product test reports with the structure and terminology mandated in the latest standards for ease of review by authorities and customers.

Conclusion / Next Steps

December 2025’s standards release represents a significant step forward for the reliability, precision, and interoperability of telecommunications, audio, and video engineering systems. For organizations in this field, rapid adoption of:

• The new distributed fibre optic strain sensing protocols (IEC 61757-1-4:2025)
• Advanced FM receiver measurement methods (IEC 60315-4:1997)
• Robust HN RF connector specifications (EN IEC 61169-74:2025)

will deliver competitive benefits and future-proof vital infrastructure.

Recommendations:

• Audit current equipment and procedures against these new standards
• Update internal design, procurement, and QA checklists
• Train technical staff on new compliance requirements
• Explore and procure the latest standard documents via iTeh Standards for in-depth implementation support

Stay tuned for future installments in this 7-part series for a complete view of all recent standards impacting telecommunications, audio, and video engineering. To maintain your organization’s edge, make standards-based compliance and innovation a core part of your 2026 strategy.