Some Basic Concepts of Translators and Identifiers Used in Telephone Switching Systems

Those concerned with the technical details of automatic telephone switch" ing circuits usually regard a switching system as made up of a number of types of blocks or elements named in accordance with their main accomplishment in the train of events in handling a telephone call. Each of these elements is important as a useful cog in making the system work. Some of them, however, have an added distinction, if not a glamour, because their introduction to the switching world made possible fundamental changes in switching technique or in the service which could be offered to subscribers. Two such elements are translators and identifiers. They will not be defined or explained until later, but a few words concerning their importance may be in order here. These elements were not used at all in early types of automatic switching systems. The invention of the translator in 1905, by Mr. E. C. Molina, 1 and the philosophy that accompanied it are now generally credited with having laid the groundwork for the Bell System's adoption of systems of the common control type. In these, the paths necessary to reach a called number are not selected by the calling dial but by equipment which is common to many switching elements. The dial merely furnishes the customer's orders to the common equipment which, through the translation process, can set up a more suitable series of paths than is possible within the limitations of direct dial control. 1