 industry. As in her previous editions, she presents a good balance of technical and business-related information that is readily understandable by anyone with an interest in this key component of today's business environ- ment. In her new edition, she has captured many of the recent changes in this dynamic field, which will affect every company in the years ahead. I strongly recommend her book to anyone who wants a better understanding of telecommunications." -Joe McGrath, SVP, Information Technologies, Sunovion Pharmaceuticals, Inc. "Dodd's work has been very helpful in the past in taking complex technical topics and translating them into actionable business items for my MBA students. Her book doesn't gloss over the details, but rather explains why they are important in the twenty-first century information age." -Andrew Urbaczewski, Ph.D., Chair, Department of Management Studies, Associate Professor of MIS, College of Business, University of Michigan-Dearborn Essential Guide to Telecommunications Fifth Edition This page intentionally left blank Essential Guide to Telecommunications Fifth Edition Annabel Z. Dodd PRENTICE Upper Saddle River, NJ Boston Indianapolis San Francisco New York Toronto Montreal London Munich Paris Madrid Capetown Sydney Tokyo Singapore Mexico City Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and the publisher was aware of a trademark claim, the designations have been printed with initial capital letters or in all capitals. The author and publisher have taken care in the preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information or programs contained herein. The publisher offers excellent discounts on this book when ordered in quantity for bulk purchases or special sales, wh