Proposed longitudinal induction test circuit for digital subscriber lines

A test circuit for analyzing in the laboratory the performance of a digital subscriber line (DSL) under the influence of 60-Hz longitudinal power induction is proposed. The two-wire DSL transmission system, consisting of a nonloaded telephone circuit the line termination (LT) at the central office end, and the first network termination (NT1) at the subscriber end, is subject to the interfering effects of long-term steady-state induction from exposure to electric power systems in the outside plant. Therefore, there is a need for a test circuit to analyze DSL performance in the presence of steady-state induced voltage. The proposed induction test circuit and the accompanying criteria are intended to ensure reliable performance of ISDN (integrated services digital network) access services in the expected induction environment.<>