Supplement 47 to ITU-T G-series Recommendations provides information on the generaltransmission characteristics of single-mode optical fibres and cables specified in the ITU-T G.65x-series of Recommendations related to the practical use condition.It covers the environmental and length-related characteristic of ITU-T G.65x-series optical fibres and cables.The fibre material-related characteristics are also described in Appendix I.Version 2 of this supplement introduces the general aspect of multi-path interference (MPI) in an optical fibre in order to support newly established test methods for coherent MPI which can be found in Appendix IV of Recommendation ITU-T G.650.1.