GB1167998A - Improvements in or relating to Telecommunications Exchange Systems - Google Patents

Abstract

1,167,998. Automatic exchange systems. SIEMENS A.G. 26 July, 1967 [27 July, 1966], No. 34208/67. Addition to 1,077,679. Heading H4K. In an exchange system having a switching network through which paths are selected with the aid of a simulation network, each of the latter's outlets (d, Figs. 3 and 6) is connected to one input of an individual threeinput AND gate KG. The gate's other two inputs c and r are energized respectively by a signal indicating the free condition of the corresponding outlet from the switching network and by a signal from the marker indicating that the gate corresponds to an outlet in a desired direction (as indicated by the registration and translation of dialled digits). The AND gates are arranged in sets e.g. one set per switch (the switches themselves being arranged in groups, c.f. the Parent case), each set being connected via a multi-input OR gate (diodes G1-G10) and further OR (G101-G110) and AND (UZ1 ) gates to a common multiple MRK extending to the marker AMK. The latter with the aid of ring-like, one-only selectors SU1- SU3 chooses one out of all the triply marked AND gates that appear during route finding. Selection of one switch in the last stage causes a marking to be extended back through the simulation network (contacts, e.g. Z1 in Fig. 4, not shown) to the previous stage where a similar selection takes place. With the fourstage network shown (and also Figs. 1 and 3, not shown), further selection is not then necessary in the second stage since the path through it is by now uniquely determined. The order of priority in respect of outgoing routes is exercised by a stepping register BW and the various translation fields UR, ZR, BR and RF.