IEC 60875-1:2015 applies to non-wavelength-selective fibre optic branching devices, all exhibiting the following features:- they are passive, in that they contain no optoelectronic or other transducing elements;- they have three or more ports for the entry and/or exit of optical power, and share optical power among these ports in a predetermined fashion;- the ports are optical fibres, or optical fibre connectors. This standard establishes uniform requirements for the optical, mechanical and environmental properties. This sixth edition cancels and replaces the fifth edition published in 2010 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:- removal of terms and definitions for splitter, coupler, symmetric non-wavelength-selective branching device, asymmetric non-wavelength-selective branching device;- addition of terms and definitions for bidirectional non-wavelength-selective branching device and non-bidirectional non-wavelength-selective branching device, removal of assessment level.Keywords: non-wavelength-selective fibre optic branching devices, uniform requirements for the optical, mechanical and environmental properties.