Excerpt from Telephony, Vol. 2 of 6: A Manual of the Design, Construction, and Operation of Telephone Exchanges; Switchboards and the Central Office, With Illustrations The Central Office is the brain of the telephone ex change. From it the wire plant, a complicated ganglion of nerves, radiates in all directions. In it originates that mysterious electric energy that, thrilling over the circuits, animates and operates the whole. Within a decade central office practice has been twice revolutionized. The branch terminal switchboard has displaced the series multiple, and it in turn has been driven forth to make way for the com mon battery automatic signal board. So rapid have been these changes that one can scarcely catch breath to cry, What next! Just now the perfection attained by the com mon battery board has, at least for the moment, halted the march of invention, and seizing this opportunity, the author is endeavoring to place before his readers a brief account of the central office and its various organs as it exists today. The central office consists of four parts. The ter minals, the switchboard, the battery plant, and the build ing; to each of which a section of the volume is assigned. There is no end to circuit possibilities, and the author knows of but one complete collection of the successful devices of the day, so it is hoped that the chapter on Common Battery Boards will place in the hands of the student a more comprehensive view than is to be found. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.