New concepts in exchange outside plant engineering

Concentrated study by the American Telephone and Telegraph Co. and Bell Telephone Laboratories has resulted in several engineering and design innovations that permit more efficient utilization of the exchange cable network. As a first step, a mathematical model of the customer loop plant was developed from survey data. With this model, studies have been made of the transmission properties of the loop plant at both voice-band and carrier frequencies via computer analysis. Results of such studies have been useful in planning plant improvement programs and have also been used to evaluate such new concepts as “dedicated outside plant” and “uniform-gauge customer cable plant.” Other computer programs have been and are being developed to aid in engineering cable routes for future growth and to evaluate alternatives to placing new cable, such as concentrators and exchange carrier systems. Studies to optimize the placement of new switching centers, taking into account existing wire centers and forecasts of growth for the area, have been made by computer analyses. These computer programs aid engineers in making studies in much more depth and in less time than was possible with older cut-and-try methods.