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 singlemode resilient alignment sleeve LX.5 PC connector set (plug/ adaptor/ plug) should meet in order for it to be categorised as an EN standard product. Since different variants and grades of performance are permitted, product marking details are given in 3.6. 1.2 Intermateability Although all products conforming to the requirements of this European Standard will intermate, the resulting level of random attenuation performance will only be ensured in accordance with Table 1. The intention is that this will be true irrespective of the manufacturing source(s) of the product. When intermating plug variants having different attenuation grades, the resulting level of attenuation cannot be assured to be any better than the worst attenuation grade. The intermating of a grade C plug with a grade B plug will result in an uncertain level of random attenuation performance. Table 1 - Ensured level of random attenuation 1.3 Operating environment The tests selected combined with the severities and durations are representative of a category U environment described in EN 61753-1. 1.4 Reliability Whilst the anticipated service life expectancy of the product in this environment is 20 years, compliance with this specification 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 specification does not guarantee the manufacturing consistency of the product. This should be maintained using a recognised quality assurance programme.