Problems of Long-Distance Telephony at the Turn of the 19th and 20th Centuries and the Search for Their Solutions

At the turn of the 19th and 20th centuries, long-distance telephone communication turned into a serious business, however, the cost of lines was high, and the practical commercial range of telephone signal transmission did not exceed 1600 km. As the lengths of long-distance telephone lines increased, two problems arose that were rec-ognized as particularly relevant, in particular, crosstalk and signal attenuation. AT&T researchers were engaged in solving these problems. This article examines the work of scientists and engineers who have led to real practical solutions to problems of long-distance telephone communication, in particular, Oliver Heaviside, John Stone and George Campbell.