The Trend in the Design of Telephone Transmitters and Receivers

N the beginnings of the telephone, the outstanding marvel was that the devices used as transmitters and receivers could perform the necessary conversions between speech sound waves and electrical waves. In the application of these devices, however, it was early appreciated that the range and cost of telephone circuits were directly 1 E D I T O R ' S N O T E : In this issue of the Bell System Technical Journal there are two papers and one report dealing with various phases of the inductive coordination problem, which have had their origin in the work of the Joint Subcommittee on Development and Research of the National Electric Light Association and the Bell Telephone System. This organization is one of the subcommittees of the Joint General Committee of the N.E.L.A. and Bell Telephone System, which has for its general objective the working out of methods of procedure whereby problems involving the physical relations between the plants of the electric supply companies and the telephone companies may be handled cooperatively on mutually satisfactory bases. The questions involved are largely of an engineering character, and to carry on that phase of the work the Engineering Subcommittee of the Joint General Committee was appointed. The Engineering Subcommittee has recommended certain broad principles of cooperation as well as the adoption of more detailed principles and practices, which were accepted by the Joint General Committee and published in 1922. As a result of further recommendations by the Engineering Subcommittee the Joint Subcommittee on Development and Research was organized.