Overview
IEC 61754-20:2012 specifies the standard interface dimensions and intermateability rules for the Type LC connector family used in fibre optic interconnecting devices and passive components. This edition revises the original 2002 standard and adds specific interfaces (IEC 61754-20-9 to 20-16) for plastic optical fibre (POF). The standard covers simplex and duplex plug, adaptor and active-device receptacle interfaces, ferrule/endface types (PC and APC) and the special cases for 1.25 mm ferrules and 1 mm POF.
Keywords: IEC 61754-20, LC connectors, LC connector family, fibre optic connectors, POF, ferrule, PC, APC
Key topics and technical requirements
- Interface definitions: Standard interfaces for simplex and duplex plugs, adaptors and active-device receptacles (Interfaces 20‑1 through 20‑16).
- Ferrule and fibre types:
- Nominal 1.25 mm ferrule for metal/glass fibres.
- POF support: 1.25 mm jacketed OD (with fibre up to 0.75 mm in ferrule) and 1 mm POF (no ferrule).
- Endface geometry:
- PC (physical contact, spherical) and APC (angled physical contact, 8°) endface types for metal/glass ferrules.
- Flat smooth endface for POF plug interfaces.
- For detailed end-face geometry, normative reference to IEC 61755-3 series is required.
- Mechanical features:
- Single coupling latch, single male key for orientation, ferrule spring loaded along optical axis.
- Optical alignment via rigid bore sleeves or resilient sleeves; adaptor and receptacle dimensional drawings define critical mating features.
- Intermateability rules:
- Tables and figures define which plug types mate with which adaptors and receptacles and plug-to-plug compatibility (e.g., PC vs APC vs POF interactions).
- Documentation content: Contains figures, detailed tables of dimensions, adaptor options (simplex, duplex, quad), and active device receptacle pin gauge and sleeve grades.
Practical applications and who uses this standard
- Connector and transceiver manufacturers - to design LC plugs, adaptors and receptacles that are mechanically and optically intermateable.
- System integrators and network equipment vendors - to select compatible LC connector components for patch panels, transceivers and active devices.
- Test laboratories and certification bodies - to verify compliance against defined interface dimensions and intermateability rules.
- Procurement and quality teams - to ensure purchased LC connectors meet IEC interface standards and will mate with existing infrastructure.
- Design engineers - when integrating POF solutions alongside standard glass/multi-mode deployments.
Related standards
- IEC 61755-3 series - end-face geometry requirements for PC and APC interfaces (normative reference).
- Other parts of the IEC 61754 series - for other connector families and additional interface specifications.
IEC 61754-20 is essential reading for anyone specifying, designing or verifying LC connectors and their interchangeability across fibre optic systems, including recent POF applications.
Open preview (PDF)Fibre optic interconnecting devices and passive components - Fibre optic connector interfaces - Part 20: Type LC connector family
