A modern automatic telephone apparatus

The writer presented a paper before the annual convention of the Institute in 1908, dealing with automatic telephone equipment from an economic viewpoint.∗ The present paper will therefore be principally devoted to a description of the apparatus used and its method of operation in modern plants. Although there are several different types of automatic telephone equipment upon the market or being developed, practically all of the working plants use apparatus of the “Strowger” type with or without the addition of Keith line switches. Since this paper must be confined to one system, only the one which is extensively used will be discussed. The description will begin with a short reference to the subscriber's station equipment.