Loop Plant Modeling: Economic Evaluation of Subscriber Pair Gain System Applications

Economic Evaluation of Subscriber Pair Gain System Applications By W. L. G. KOONTZ (Manuscript received August 20, 1977) In recent years, the cost of subscriber pair gain systems, i.e., systems which enable more than one subscriber to be served by a single cable pair, has decreased significantly in comparison with cable. Moreover, the operating expenses associated with an all-cable loop network have increased along with the cost of labor, particularly in areas of high customer mobility and uncertain growth. For these reasons, the application of pair gain systems has become an important consideration in loop plant design. This paper presents and discusses a series of subscriber pair gain system applications. Given the forecast requirement for loop facilities, one may use these models to evaluate and compare alternatives for meeting this requirement on a present worth basis. The alternatives may include cable only, pair gain systems only, or a combined cable/pair gain alternative (deferred cable). These models have been applied in Bell Laboratories studies of the market for pair gain systems. They are now being incorporated into guidelines which will enable the operating companies to apply pair gain systems in an economic manner. I. INTRODUCTION mathematical models which can be used in the economic analysis of Subscriber pair gain systems, which use carrier and concentrator techniques to reduce requirements for loop cable, have been available since the 1950s. Until recently, however, their high cost relative to cable has limited their application to very long rural routes requiring expensive coarse-gauge cable.