GB1275520A - Improvements in or relating to telecommunications exchange systems - Google Patents

Abstract

1275520 Automatic exchange systems SIEMENS AG 30 July 1970 [31 July 1969] 36893/70 Heading H4K In a 4-wire PCM, TDM transit exchange, separate time-slot-matching intermediate stores are provided for each direction of transmission. An incoming highway PCMek which may be provided with a flywheel circuit R for deriving a sync. pulse train from the digital signals on the highway, is cyclically gated (ekk) to an intermediate store Vkg. This may be a shift register which is stepped by the sync. pulse train applied via gate ekH that is opened in synchronism with ekk by an address located in circulating memory Uek. The output from Vkg is gated (Ksg) in a similar manner to an outgoing highway PCMsg. In the opposite speech direction e.g. PCMeg and PCMsk another store Vgk is utilized. The stores may be used for more than one call at a time if they are not occupied on one call for the full duration of a cycle. The outgoing highways are synchronized by deriving the everage pulse pattern (M) of the patterns produced by the incoming highway circuits R. The average pattern is injected with each outgoing highway via gates e.g. Hsg. Each highway preferably has access to five intermediate stores (Fig. 3a, 3b, not shown) possibly via a two stage space division network (Fig. 3c, not shown).