Electronics in the Suburban and Light Urban Loop Networks

Loops are the facilities between the local central office and the subscriber. For the most part, the individual customer's loop is a pair of metallic conductors. The cost of the loop network has risen as a result of both material and labor inflation. Labor costs directly affect the cost of the loop plant because labor composes roughly 75 percent of the total expenditures in the loop plant. 1 While loop construction costs have increased with inflation, the cost of electronic alternatives has actually decreased. Two basic types of electronic alternatives to standard cable relief (Fig. 1) are range extension and pair gain systems. Range extension permits the design of the loop plant with finer gauged cables, which reduces cable relief costs. The range extender is an electronic device that extends the central office supervisory range and provides voice frequency gain to compensate for the higher loss of the cable plant. 417 Fig. 1--Loop alternatives.