Telecommunication exchange system with integrated test facility - has manual or automatic test desk replacing subscriber's appts. and having additional test voltage lines

摘要

A central test desk provides access to any equipment item via the selection network such as the coupled field and central exchange with its switch control unit. One or more extra lines per satellite exchange are provided for d.c. test voltages and currents. The address and selection function is performed by using the existing exchange selection units. A small supplementary coupled field, additional to the existing one, can be installed, in order to ensure suitability for d.c. passage, but even in that case the transmission of the selection signals between coupled field and the satellite exchanges is carried out over the existing multiplexed signalling channels and not via the special direct current test links.