GB166375A - Improvements in or relating to telephone systems - Google Patents

Abstract

166,375. Automatic Telephone Manufacturing Co., Ltd., and Gillings, C. April 27, 1920. Automatic exchange systems.-In systems in which each subscriber has a non-numerical line switch, a fixed group of trunks, equal in number to the positions of the line switches, is made accessible to a computed number of subscribers, thus enabling a more accurate adjustment of the traffic to be made than in the customary arrangement, in which a fixed group of subscribers is given access to a computed number of trunks. For example, in the system illustrated, in which 200 subscribers are each equipped with a line switch having 25 positions, computation may show that the first group of 25 selectors A can handle the traffic of subscribers 1 to 91, and that the second group of 25 selectors B can handle the traffic of subscribers 92 to 194, the residue being dealt with by a few additional selectors C. The line switches are arranged in eight sets of 25, all the corresponding terminals in each set being multipled to groups of trunks D .. G and L ..O, there being 25 trunks in each group corresponding to the 25 positions of each switch. The trunks D, E, F are all multipled together and to the selectors B at K, but of the trunks G, 16 are multipled to selectors A and 9 to selectors B, and of the trunks O, 19 are multipled to selectors B and 6 to selectors C. Thus 16 out of 25 calls through the fourth group of line switches go to selectors A, the other- 9 going to selectors B; and 19 out of 25 calls through the eighth group of line switches go to selectors B, the other 6 going to selectors C; so that in effect, though not literally, the selectors A serve the first 91 subscribers and the selectors B serve the next 103 subscribers. The invention consists particularly in this method of dividing- the calling lines into groups of irregular size while keeping the line switches in sets of a standard number.