Telephone exchange coupling field control matrix - has testing switching unit for fault localisation

摘要

The control matrix comprises row and column lines, with each row line associated with a row contact also acting as a switch contact for fault localisation and connecting it to one of two control lines. Each column has two column lines, the first of which is connected to a respective switch contact of a first set, and the second of which is connected to a respective switch contact of a second set. Each set of contacts is connected to a respective current monitoring device, with each of the latter connected via the respective contacts with a rectifier associated with each column line. A coupling relay is associated with each pair of column lines along each line, with the rectifiers associated with each column line connected to the coupling relay.