Testing basic access loops for service-affecting impulse noise

The implementation of basic access ISDN (integrated services digital network) using the standard Digital Subscriber Line (DSL) will convert the local loop to a digital transport facility. The author suggests procedures for determining whether a basic access loop is subject to service-affecting impulse noise and describes the technical parameters of instruments that would be used to make that determination. The standard DSL will be a robust technology that will be largely immune to the effects of impulse noise. It is recommended that loops carrying DSL signals be tested for impulse noise only when the other maintenance tests have failed to reveal the source of customer trouble. Specifically, it is not recommended that impulse noise testing be part of a routine loop-qualification procedure. Results of impulse noise studies suggest that an errored second objective be used to determine whether impulse noise will affect service on loops carrying DSL signals. The author proposes a measurement procedure that uses currently available impulse noise tests sets to estimate the errored second performance of a DSL on a given loop