This part of IEC 60875 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.