Schaltungsanordnung fuer Fernmelde-, insbesondere Fernsprechanlagen mit Koppelfeldern und weitspannender Wegesuche

1,130,982. Automatic exchange systems. SIEMENS A.G. 24 Aug., 1966 [25 Aug., 1965], No. 37865/66. Heading H4K. A multistage switching network, in which each stage is divided into switching frames, TKP11-TKF10 and TKF21 - TKF20, has a control device ST and path seeking circuit W associated with each frame, an allotter Z common to the network effecting connection between the control devices ST in successive stages by way of switch KST, and similarly connecting the path seeking circuits by way of switch KW, so that a common path seeking operation can be conducted across the network in accordance with the route required. The switches KST and KW may be a single switch. The route required by a line, seen to be in a calling condition by a scanner such as S11, is determined by a receiver/sender such as ES11 connected to the calling junction circuit over switch K11. Supplied with sufficient digits, stored in the control device ST11, the common allotter is called in to connect up the appropriate control device and path seeking circuit in the next stage. Path seeking may be done by the examination of stores containing a record of the switch frame idle/busy conditions in which case the network contacts are preferred to be of a latching type. The control devices ST of each stage are such that if one such device fails another can take over the function and control two switching frames. Backward signals may be sent without involving the network proper, the signals being sent via the receiver/senders ES and control devices ST linked by the switch KST.