1.1 Product definition This European Standard contains the initial, start of life dimensional, optical, mechanical and environmental performance requirements which a terminated and assembled 12-fibre multimode MPO connector set (plug adapter plug) must meet in order for it to be categorised as an EN standard product. Since different variants are permitted, product marking details are given in 3.5. 1.2 Intermateability All products conforming to the requirements of this standard will intermate and give the specified level of random attenuation and random return loss performance provided the same core size is used. The intention is that this will be true irrespective of the manufacturing source(s) of the product. 1.3 Operating environment The tests selected combined with the severity and duration are representative of a backplane/back panel indoor application derived from customer premise protected environment as defined in EN 50173 series and ISO/IEC 11801 and as specified in category C per EN 61753-1. 1.4 Reliability Whilst the anticipated service life expectancy of the product in this environment is 20 years, compliance with this standard does not guarantee the reliability of the product. This should be predicted using a recognised reliability assessment programme. 1.5 Quality assurance Compliance with this standard does not guarantee the manufacturing consistency of the product. This should be maintained using a recognised quality assurance programme.