IEC 61935-2-20:2008

Overview

IEC 61935-2-20:2008 is an international standard published by the International Electrotechnical Commission (IEC) that outlines the blank detail specification for patch cords and work area cords used in Class D applications. This standard supports testing balanced communication cabling in accordance with the globally recognized ISO/IEC 11801, which specifies generic cabling for customer premises. The document serves as a technical revision and replaces ISO/IEC PAS 61935-2-20 (2007), setting forth guidelines for detail specifications of cords designed for transmission frequencies up to 100 MHz, crucial for digital communication systems.

The blank detail specification aims to standardize the layout, style, and key performance criteria for cords used in work area installations, ensuring interoperability and quality across manufacturers, national organizations, and users.

Key Topics

Scope and Purpose

• Describes balanced communication cables, specifically work area cords and patch cords for Class D applications.
• Defines transmission parameters up to 100 MHz suitable for digital communication networks.
• Provides a framework for creating detailed product specifications based on a blank template.

Structure of Detail Specifications

• Specifies the layout format detailing:
  • Category designation (Class D / Category 5e enhanced).
  • Nominal impedance and cable construction.
  • Transmission characteristics and connector types.
  • Mechanical, electrical, and environmental performance parameters.

Testing and Compliance

• Test configurations refer to IEC 61935-2, which defines how cords should be tested.
• Emphasis on maintaining impedance, insertion loss, return loss, and crosstalk performance in line with IEC 61156 and IEC 60603 connector standards.
• Physical robustness assessed via tensile strength, bending radius, impact resistance, and environmental endurance tests based on MICE (Mechanical, Ingress, Climatic, Electromagnetic) severity levels from ISO/IEC 24702.

Environmental and Mechanical Requirements

• Defines operating temperature ranges typically from -40°C to +70°C across different severity levels.
• Specifies minimum bending radius values for static and dynamic conditions.
• Addresses resistance to dust, water immersion, salt mist, sulfur dioxide, solar radiation, solvents, and mechanical vibrations ensuring reliable operation in harsh industrial and commercial environments.

Guidance for Specification Preparation

• Instructions to use placeholders such as “na” (not applicable) or “ns” (not specified) to tailor characteristics.
• Calls for inclusion of manufacturer details, cable descriptions, and references to normative documents like IEC 61156-6 and IEC 62012-1.
• Focus on meeting coupling attenuation, transfer impedance, and screening attenuation criteria for electromagnetic compatibility.

Applications

IEC 61935-2-20:2008 is primarily applied in the design, testing, and certification of patch cords and work area cords in Class D network environments, commonly found in:

• Enterprise LANs supporting digital voice, video, and data communications.
• Structured cabling installations conforming to ISO/IEC 11801.
• Industrial premises requiring reliable industrial-grade communication cabling as per ISO/IEC 24702.
• Manufacturers aiming to develop or certify new cord products that comply with international performance and compatibility standards.
• National standards bodies tailoring detail specifications for local cable markets using the IEC blank template.

By ensuring standardized testing and construction criteria, this standard promotes consistent quality, interoperability, and network performance, especially for networks utilizing Ethernet transmissions up to 100 MHz.

Related Standards

Understanding and applying IEC 61935-2-20 requires familiarity with several interconnected IEC and ISO/IEC standards:

• ISO/IEC 11801: Generic cabling for customer premises - foundational for structured cabling systems.
• IEC 61935-2: Testing of balanced communication cabling - provides test methods for patch cords and work area cords.
• IEC 61156-1 / IEC 61156-6: Specifications for symmetrical pair/quad cables, including transmission performance.
• IEC 60603-7-2 / IEC 60603-7-3: Specifications for connectors used in balanced communication cabling.
• IEC 62012-1: Specifications for cables used in harsh industrial environments.
• ISO/IEC 24702: Generic cabling for industrial premises.
• EN 50289-1-13: Electrical test methods for coupling attenuation applicable to patch cords (to be replaced by IEC equivalent).

Adhering to this suite of standards ensures that patch and work area cords meet rigorous requirements for electrical performance, mechanical durability, and environmental resistance essential for modern communication networks.

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Keywords: IEC 61935-2-20, balanced communication cabling, Class D applications, patch cords, work area cords, ISO/IEC 11801, Category 5e, transmission characteristics, network cabling testing, structured cabling standard, IEC testing method.