DIGITAL SUBSCRIBER LINE (HDSL AND ADSL) CAPACITY OF THE OUTSIDE LOOP PLANT

The fundamental limits of the outside loop plant to carry high-speed d igital (bi-directional HDSL and ADSL) data are reported. The paper foc uses on the copper wire pairs, drop lengths, and interconnects that co nvey data over the ''last mile'' to almost all businesses and residenc es in the US. The two major customers, businesses and households, are classified, characterized, and categorized by the distance to the cent ral office or the remote terminal. Their spectral capabilities are com puted and their ultimate digital capabilities are reported. The crosst alk limitations inherent in the plant are also computed and verified a gainst the loss of signal due the distance and spectral constraints, T he signal to noise ratio can thus be estimated to ascertain the transm ission quality through the plant. Accordingly, the paper reports on lo sses, bandwidths, and bit rates in the first half, and discusses the m ajor bottlenecks in the second half.