An Experimental Local PCM-Switching System

This paper discusses a local PCM switching network. The characteristics of this network are demonstrated with a model of three local exchanges. All subscribers are connected with the exchange via concentrators. An exchange is controlled by a central processor with a stored program. This processor interacts with the peripheral switching units, represented by the central switching network and two types of control circuits, located within the exchange. These control circuits control either the concentrators or they communicate with counterparts, situated in other local exchanges. All control functions that are not executed by programs of the central processor are realized by microprograms in a wired read-only storage (ROS) in these peripheral control circuits.