This Recommendation describes the geometrical and transmission attributes of single-mode optical fibre and cable with chromatic dispersion and cut-off wavelength that are not shifted from the 1310 nm wavelength region. Definitions and test methods are contained in a separate ITU-T G.650. Tables of recommended values for different sub-categories of this fibre type are provided to allow ease of reference with regard to the type of system that is supported. Sub-categories described in the tables may differ for technological aspects or for the intended application. Allowed ranges are recommended for both fibre and cable attributes. Information for link attributes and system design is found in Appendix I.