Translation with magnetic drum in electronic automatic exchange

IN COMMON-CONTROL systems, the telephone number dialed on a call merely identifies the destination of the call in terms of a uniform numbering plan; the dialed digits cannot control the switching operation directly. A translator is required in order to determine, by referring to information previously stored, the proper routing of the call and the controls required for completing the call over this route, and then to initiate these controls. The information required for such translation may be stored by making appropriate connections within the switching equipment (e.g., on distributing frames and in jumper fields); this is the method employed in electromechanical switching systems. The information may be said to be permanently stored, since it can be changed only by rearranging the jumpers.