IEC 60794-3-12:2021 is available as IEC 60794-3-12:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 60794-3-12:2021 is a detailed specification for duct and directly buried optical telecommunication cables for use in premises cabling to ensure compatibility with ISO/IEC 11801-1. This document's requirements ensure that the ISO/IEC 11801-1 models work for generic cabling and system performances. Values in this document support these models. The requirements of the family specification IEC 60794-3-10 are applicable to cables covered by this document. Particular requirements detailed in Clause 5 either define a specific option relative to the requirements of IEC 60794-3-10 or define additional requirements. This third edition cancels and replaces the second edition published in 2012. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - addition of references to ISO/IEC 11801-1; - removal of references to ISO/IEC 24702; - incorporation of the OM5 cabled fibre performance category; - incorporation of the OS1a cabled fibre performance category; - cabled fibre performance categories OM1, OM2 and OS1 are no longer normative, and are retained for information.