ITU-T L.19 PDF

This Recommendation deals with the general considerations and the requirements of the digital local line characteristics, which are used between the line termination and the network termination, to provide ISDN and xDSL services. The field of home network is not addressed in this Recommendation. Moreover, this Recommendation describes the guidance for the use of multi-pair copper cable supporting shared multiple services such as ISDN/xDSL.

The values used in this Recommendation are based on a number of DSL technologies as they are known at the moment of publication of this Recommendation. However, the general principles are applicable to any type of DSL technology, generally referred to as xDSL.