This standard BS EN 61755-3-5:2006 Fibre optic connector optical interfaces is classified in these ICS categories:
33.180.20 Fibre optic interconnecting devices
This part of IEC 61755 defines dimensional limits and material properties of a 2,5 mm and a 1,25 mm diameter cylindrical composite ferrule optical interface to meet specific requirements for PC fibre-to-fibre interconnection.