This Recommendation gives the recommended criteria for the detection and clearance of LOS, AIS and RDI defects at intra-station interfaces conforming to Recommendation G.703 and operating at bit rates described in Recommendation G.702. The information provided complements the information on fault and consequent action given in the G.730-, G.740- and G.750-series Recommendations. Appendix I contains examples of the criteria used in equipment that has been designed prior to the development of this Recommendation.