This part of IEC 60793 establishes uniform requirements for measuring the cut-off wavelength of single-mode optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes. This standard gives the methods for measuring the cut-off wavelength of fibre and cable There are two methods for measuring cable cut-off wavelength, ë cc: - Method A: using uncabled fibre; - Method B: using cabled fibre. There is only one method (Method C) for measuring fibre cut-off wavelength, ë c. The test method in this standard describes procedures for determining the cut-off wavelength of a sample fibre in either an uncabled condition (ë c) or in a cable (ë cc). Three default configurations are given here: any different configuration will be given in a detail specification. These procedures apply to all category B and C fibre types (see Normative references). All methods require a reference measurement. There are two reference-scan techniques, either or both of which may be used with all methods: - bend-reference technique; - multimode-reference technique using category A1 multimode fibre.