This Recommendation describes the testing procedures for ITU-T Digital Subscriber Line (DSL) Recommendations. The testing procedures described herein include methods for testing DSL transceivers in the presence of crosstalk from other services, Radio Frequency ingress, impulse noise and POTS signalling. Test loops and in-home wiring models are specified for different regions of the world for use during DSL performance testing. Other DSL Recommendations reference this Recommendation for testing procedures and configurations. This Recommendation does not specify performance requirements for these other Recommendations; it only specifies the procedures for measuring the performance requirements for a particular Recommendation.