The topics in this video course provide the essential foundation on which everything else, including digital communications, data circuits and networking are built. It starts with the Public Switched Telephone Network (PSTN) and fundamentals that are key to understanding of newer technologies and services. Take a practical journey through different types of equipment including switches, PBXs, Centrex, multiplexers and routers, as well as ancillary equipment. View the telecommunications industry and understand the main players and competitors, how Local Exchange Carriers connect to Inter-Exchange Carriers and how CLECs fit into the picture.