Outside Plant—Metallic Pair Systems

Abstract Outside plant is defined as “the part of the telephone system that is located physically outside of telephone company buildings. It includes wire‐pair cables, the wire‐pairs themselves, supporting structures, and certain equipment items such as load coils.” This chapter provides design and interface information on wire‐pair systems including the subscriber loop and subset, wire‐pair trunks (junctions), outside plant construction, and layout. Wire‐pair systems are just now coming into their own with DSL (digital subscriber line) techniques. For years, wire pair has been undersold even though it was the backbone of the subscriber plant, taking up about 15–20% of the total investment of the local telephone company. There were two driving forces that brought about this new view. First it was the telephone company attempting to compete with entrenched CATV operators to provide a similar service using existing wire‐pair plant. The second force was the need for downstream high‐speed (>1 Mbps) internet service.