The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 122
Switch.—There are a numberof different patterns of these switches, bydifferent makers. Perhaps the most common, and a verysatisfactory form of automatic switch, isthat introduced by the Western ElectricCo., and shown in Figs. 92 and 93. Thestrong spring d serves both as the bell-contact spring and… … Fig. 91
Telephone
Internet Archive · Northeastern University Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer01inte-144-51.webp)
![An illustration from The Telegrapher [microform] (1864)](https://img.insideoutlibrary.com/img/200/ia-telegrapher05nati-269-176.webp)
