UNE-EN 61755-3-5
Fibre optic connector optical interfaces - Part 3-5: Optical Interface - 2,5 mm and 1,25 mm diameter cylindrical PC composite ferrule using Cu-Ni-alloy as fibre surrounding material, single mode fibre (IEC 61775-3-5:2006). (Endorsed by AENOR in April of 2007.)