This quintessential guide to early twentieth-century communication technologies and systems provides valuable information on telephone and telegraph networks, as well as municipal electric fire-alarm and police patrol signaling systems, in the United States. Richly illustrated and meticulously researched, this book serves as a reference for historians, engineers, and anyone interested in the development of modern technology. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.