IEC 60793-1-1: 2017 lists and gives guidance on the use of documents giving the uniform requirements for measuring and testing optical fibres, thereby assisting in the inspection of fibres and cables for commercial (mostly telecommunications) purposes. The individual measurement and test methods are contained in the different parts of the IEC 60793 series. They are identified as IEC 60793-1-X, where X is an assigned sub-part number, indicating its affiliation to the IEC 60793-1 series. In general, measurements and tests methods apply to all class A multimode fibres and class B and class C single-mode optical fibres covered by IEC 60793-2 (all parts) relating to product specifications, although there can be exceptions. Clause 1 of each part of the IEC 60793 series contains the scope for each particular attribute. This fourth edition cancels and replaces the third edition published in 2008. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: addition of rounding rules in Clause 4; addition of two packaging requirements in Clause 10d) and e).