Evolution of the Italian Telecommunication Network towards SDH

The digitalization of both transmission and switching facilities as the basis for both a high standard quality of service and the introduction of advanced network features (like intelligent network and integrated services digital network, or ISDN) is described. The development of synchronous digital hierarchy (SDH) systems is discussed, with particular attention given to the add-drop multiplexer and to management issues. The impact of the new SDH transmission equipment on the present plesiochronous network is assessed. The currently envisaged strategy for introducing SDH systems into the Italian transmission network is examined. Deploying SDH systems within large metropolitan areas, both at loop plant and urban junction levels, is discussed