IEC TR 62000:2021 is available as IEC TR 62000:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC TR 62000:2021 provides guidelines concerning single-mode fibre inter-compatibility. A given category of single-mode fibre, for example B-655, can have different implementations by suitably optimising several of the following parameters: mode field diameter (hence effective area), chromatic dispersion coefficient, slope of the chromatic dispersion curve, cable cut-off wavelength. These guidelines indicate the items that are taken into account when planning to connect
- different implementations of single-mode fibres of the same category, for example different implementations of Class B single-mode fibres, and
- single-mode fibres of different sub-categories, for example B-652.B with B-655.C.
This third edition cancels and replaces the second edition published in 2010. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- global uniformity of terminology concerning fibre classes, categories and sub-categories throughout the document;
- updating and aligning to the new naming convention of IEC 60793-2-50 for class B fibre categories and sub-categories;
- updating and aligning with IEC 60793-2-50 as per supported fibre sub-categories;
- additional guidelines concerning combination of fibre parameters: chromatic dispersion and slope, polarization mode dispersion;
- additional guidelines concerning non-linear affects;
- updating of bibliographical references.