prBAS EN IEC 60793-1-40:2026

IEC 60793-1-40:2024 establishes uniform requirements for measuring the attenuation of optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes. Four methods are described for measuring attenuation, one being that for modelling spectral attenuation: -method A: cut-back; -method B: insertion loss; -method C: backscattering; -method D: modelling spectral attenuation. Methods A to C apply to the measurement of attenuation for all categories of the following fibres: -class A multimode fibres; -class B single-mode fibres. Method C, backscattering, also covers the location, losses and characterization of point discontinuities. Method D is applicable only to class B fibres. Information common to all four methods appears in Clause 1 to Clause 11, and information pertaining to each individual method appears in Annex A, Annex B, Annex C, and Annex D, respectively. This third edition cancels and replaces the second edition published in 2019. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) modifying the definition of attenuation to be compatible with the definition in <a href="https://electropedia.org/">electropedia.org</a>