GB1341487A - Telecommunications exchange systems - Google Patents

Abstract

1341487 Automatic exchange equipment SIEMENS AG 26 Aug 1971 [3 Sept 1970] 40005/71 Heading H4K A path selection network for a switching network having co-ordinate switches which do not require a holding current to maintain them in an operated state has free/busy relays with two windings and changeover contacts where one winding is an operating winding and the second winding, connected in series with the normally open contact, is connected via two similarly poled decoupling rectifiers to special row and column lines in accordance with the spatial position of the contacts. In the arrangement shown wires between adjacent cross-point switches are represented as the rows and columns respectively of the matrix shown and marking occurs from both ends by contacts ek1, mk1. If row contact ek1 and marker contact Zk1 are operated together the crosspoint relay EKV1 (Fig. 1, not shown) will operate together with free/busy relay Be1Z1 and contact belzl (Fig. 8) will changeover and energize holding winding II through diodes 6 and normally closed contacts el, z1 from low voltage V (There being no hold on current circuit through the cross-point switches). Release of the free/busy relay is obtained by opening the respective contact Z 1 or alternatively to ensure that all contacts representing these connections are restored to their rest position hown, the contact Z may be opened when there is no traffic on the connections. In the case where latching free/busy relays are used, the additional winding II is pulsed to effect release. In this embodiment contacts e 1 , e 10 will be normally open and are momentarily closed to effect release.