for each of a number of schaltungsanordnung mark centrally controlled telecommunications, in particular telephone, in which, in the event of an error, the stoerende, decentralized device located, and is switched off

摘要

1,206,543. Automatic exchange systems. SIEMENS A.G. 28 June, 1968 [30 June, 1967], No. 31096/68. Heading H4K. In an exchange which is centrally controlled by one of several markers at any time and in which peripheral equipments e.g. line circuits, relay sets or switching network components are arranged in groups and the groups are arranged in zones, a faulty equipment is detected and put-out of service by initially scanning the zones and then the groups within a zone and finally the units within a group in each case by successively closing normally-open contacts associated with the zones, the groups and the units, and thereafter, if the fault remains undetected, by scanning all the units in turn by opening normally-closed contacts associated with each unit. The latter scan is controlled by a random start counter which is never reset but merely starts stepping form the point reached during a search for a previous faulty equipment. It is suggested that this double scanning fault finding procedure overcomes faults arising in the fault-finding scanner itself without undue duplication of fault finding equipment. If a marker exhibits a fault, one of its partners is switched-in by the fault finder. Breakdown of a decoupling rectifier in a relay matrix, which is an example of a fault having a multiple effect, is detectable by initially locating the faulty row using the first scanning sequence and then the faulty column using the second scanning sequence.