GB593779A - Improvements in electrical signalling systems and apparatus for use therein - Google Patents

Abstract

593,779. Automatic exchange equipment. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and BAKER, G. T. June 13, 1945, No. 14948. [Class 40 (iv)] In a line identification arrangement of the kind described in Specification 539,823 in which the metering wires of the lines are connected over pairs of non-linear resistances to wires to which code markings are applied, the resistance discs pertaining to each group of e.g. 100 lines are clamped together with metal connecting plates between them to form a compact unit. The unit or block shown has 5 columns each comprising 20 pairs of discs a, b which are clamped by means of six pairs of insulated rods extending between top and bottom clamp plates. The metal plates between the associated pairs a, b are connected to the metering wires, while the other intervening plates are connected alternately to units and tens marking wires U, T, the latter set being constituted as strips extending over all the columns. In a 10,000 line exchange in which there are 100 such blocks, the tens marking wires are commoned over all the blocks having the same thousands digit, while the units marking wires are commoned over all the blocks having the same hundreds digit, thus reducing the total number of marking wires required to 200. It is sometimes preferable to employ units or blocks having a different number of pairs of discs. The blocks may conveniently be mounted on the meter rack which has a number of plates each accommodating 40 meters, and each block then consists of 40 pairs of discs arranged in two columns. The advantages of longitudinal and transverse multipling can be retained by suitable arrangement of the connections to the metering wires.