Overview
IEC 61920:2004 - "Infrared free air applications" - is an international standard published by the IEC (TC 100) that defines a classification scheme for infrared (IR) devices operating in free‑air environments across the 700 nm to 1 600 nm wavelength range. Its primary objective is to identify and reduce mutual interference between multiple parallel IR systems by specifying how IR radiators and receivers should be characterized and identified. This second edition (2004) revises the 1998 edition and is intended for use by manufacturers, system designers and facility planners.
Key topics
- Scope and exclusions
- Covers free‑air IR systems that intentionally or unintentionally emit in 700–1 600 nm.
- Excludes fiber‑optic applications and does not address safety limits for optical radiation.
- Classification criteria for IR radiators and receivers, including:
- Wavelength ranges and spectral selectivity
- Frequency/modulation characteristics
- Radiant intensity and peak intensity
- Radiation angle / beam characteristic and receiver directivity
- Duration of emission and temporal behaviour
- Receiver sensitivity, bandwidth and frequency response
- Measurement and tolerances - guidance on measurement conditions and acceptable tolerances for declared device parameters.
- Product groups and user areas - grouping IR products and typical deployment contexts to help predict interference risk.
- Interference mitigation - methods and practical measures to minimize mutual interference between systems.
- Marking and identification - requirements for labeling or documenting IR device characteristics to support coexistence.
- Relationship with other standards - references to related IEC and ISO/IEC documents (e.g., IEC vocabulary and OSI physical layer context).
Applications and who uses it
IEC 61920 is practical for:
- Manufacturers of IR transmitters, receivers and optoelectronic modules - to classify and document device characteristics.
- System integrators and facility planners - to evaluate coexistence of multiple IR systems in buildings, factories, public spaces and outdoor installations.
- Product designers of IR remote controls, IR data links, presence/motion sensors, optical wireless communications and industrial IR sensors - to reduce cross‑system interference.
- Standards bodies and procurement teams - for specifying interoperable IR equipment and harmonized marking.
Related standards
- IEC 60050 series (electrotechnical vocabulary)
- IEC 60747‑5‑1 (optoelectronic devices)
- ISO/IEC 7498‑1 (OSI model) - for relevance to physical‑layer aspects of IR information transmission
Keywords: IEC 61920, infrared free air applications, IR interference, 700–1600 nm, IR system classification, radiators and receivers, IR coexistence.
