Long-Subscriber-Route Planning and Design

Although long rural routes comprise less than 2 percent of the total Bell System loop plant, they pose serious transmission and economic problems. Planning for adequate transmission and lowest costs is facilitated by a new voice-frequency electronics plus cable design procedure that provides for an 8-dB EML and a 15-20 percent cost saving over conventional resistance design. Additional cost savings of the same order, together with improvements in noise and loss, are expected in the future through the use of distributed digital multiplexing. The rural-route data base gathered to assure accuracy in economic and service comparisons, together with the studies leading to both the near-term voice frequency plan and the ultimate multiplexing proposals, are described.