Subscriber Loops

  • Syed V. Ahamed
  • Victor B. Lawrence


Over the evolutionary phase of most voice networks, a large amount of copper in the form of wires has been used to carry electrically encoded information bearing signals. Copper is a very good conductor (resistivity 1.712×10-8 Ohms/m, 25° C) of electrical signals, being next to silver (resistivity 1.617×10-8 Ohms/m, 25° C). It is cheap, readily available, durable and ductile. For these reasons, it has been used for overhead wires, twisted wire-pairs, coaxial cables, CATV distribution, and for TV broadcast cable (twin-cable). In the context of communication networks, the copper medium has played a significant role and still retains a sizable (but diminishing) foothold in most established networks. Two well-established networks that depend heavily upon copper for distribution of information are the traditional telephone networks and the CATV networks. More recently, the impact of fiber has been dominant and resounding. Fiber as a viable alternate both for long-haul and for local distribution of information is firmly established. The impending hybrid-fiber/coax technology and cellular wireless “last mile” both pose a serious threat to the continued role of copper as an electrical signal carrier beyond the year 2020.


Image Impedance Loop Length Digital Subscriber Line American National Standard Institute European Telecommunication Standard Institute 
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Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • Syed V. Ahamed
    • 1
    • 2
  • Victor B. Lawrence
    • 2
  1. 1.City University of New YorkNew YorkUSA
  2. 2.Bell Labs Innovations Lucent Technologies HolmdelHolmdelUSA

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