isting and new service providers are leaping at its promises of wealth and riches. Out- side the United States, telecom companies once considered primitive rival the level of services offered in the United States, and in spite of the telecom meltdown that plagued the industry for several years, innova- tion continues and new players spring up like early morning mushrooms. Let's turn our attention now to the network itself. The Telephone Network "Sure, I know how it works. You pick up the phone, dial the numbers, and wait. A little man grabs the words, runs down the line, and delivers them to whomever I'm calling. It seems just about that simple. I mean, come on -how complicated can it be? It's just a telephone call." Thus was described to me the overall process of placing a telephone call by a fellow on the street, whom I once interviewed for a video I was creating about telephony. His perception of the telephone network, how it works, and what it requires to work is similar to most peoples'. Yet the telephone network is without question the single greatest and most com- plex agglomeration of technology on the planet. It extends its web seam- lessly to every country on earth, providing instantaneous communication for not only voice, but for video, data, television, medical images, sports scores, music, high-quality graphics, secure military intelligence, bank- ing information, and teleconferences. Yet it does SO with almost complete transparency and with virtually 100 percent availability. In fact, the only time its presence is noticed is when it isn't there-as happened on 2nd Avenue in New York, in Hinsdale, Illinois following a major central office fire, and in Chicago following a flood that isolated the Mercantile Exchange and placed hundreds of customers out of service. How the network works is something of a mystery to most people, SO we're going to dissect the typical telephone network and examine its anatomy, complete with pictures. This section is not for the squeamish. Downloaded from Digital Engineering