ISDN service implications arising from telephone plant testing

An ISDN basic rate loop testing field trial is described. It was found that the loop plant and the customer´s environment are not an impediment to ISDN service performance. Impulse noise originating from the older central offices was found to be the most severe performance-limiting factor. Impulse noise is propagated by the building ground system and induced into the loop pairs via the switch equipment frames. Various service implications arising from the findings are described. In particular, the access network concept allows an economical way of introducing ISDN-based services while minimizing the performance-limiting effects of noise.<>