Lightguide applications in the loop

Traditionally, the telephone network has been dominated by voice traffic. With the rapid growth in computers, integrated workstations, automated banking machines, digital PBXs (private branch exchanges), etc., today's voice network must evolve to a wideband network that can support voice, data, and video. This changing environment puts new demands on the telephone network, especially the local access portion. Accurate forecasts for new services and the mix of services are difficult to obtain. Therefore, a network must be developed that can accommodate a wide range of services and, at the same time, change as rapidly as new services evolve. Lightwave systems and digital loop carrier offer many of the characteristics necessary for this flexible network. This article describes AT&T's DDM-1000 lightwave multiplexer and SLC® Series 5 carrier system for loop applications.