Telephone

TECHNICAL v o l u m e x x x v i i Copyright 1958, American M a r c h Telephone JOURNAL 1958 and Telegraph Company n u m b e r 2 Telephone By E. T. GREEN This article, which appeared in the 1957 printing of the Encyclopedia Britannica* has been reprinted by special permission for readers of the Bell System Technical Journal. All statistics have been corrected to the latest available figures. An objective account of the invention of the telephone itself is given, and the subsequent development and growth of telephony are described. A statistical summary is presented of the intensity of development in different parts of the world. This is followed by a comprehensive review of technical developments, including progress in station instrumentalities, and transmission and switching principles and methods. The article concludes with a prediction of trends to be anticipated in telephony as a result of recent technical advances.