A Comparison of a D.C. Common Power System to a D.C. Embedded Power System in Remote Terminal Applications

In the last decade, the Telephone Industry has dramatically changed the methods for providing communication transport from business and residential customers to the local serving telephone office. The standard pairs of wires used for subscriber loops have been rapidly replaced by the use of Subscriber Loop Carrier Systems (SLC® Carrier), electrically combining groups of customers (i.e. 24) on only two pairs of wires instead of a pair per customer. The application of the latest technology has proven to be the most economical media with the added benefits of improved transmission quality and quick response to changing subscriber needs. The SLC Carriers utilize terminal equipment in the local Central Office and in a remote structure close to the end-customers. These remote structures consisted of terminal equipment mounted in bay frameworks and powered by individual-bay, embedded power systems. This study investigated the embedded power systems economics and applied typical Central Office powering architectures to the enclosures. The results indicated a common powering system is more economical than embedded systems, and increases structure circuit capacity providing the maximum benefit of the SLC Carrier technology and remote terminal structure. The economic savings and increased circuit capacity were achieved by adding a common DC power plant, designed for small applications, and replacing the individual-bay, embedded powering systems with additional terminal equipment. The power plant included a modular design facilitating the deference of power costs until the circuit growth materialized.