onka. It was set in Century Schoolbook by MacAllister Publishing Services, LLC. Printed and bound by R. R. Donnelley & Sons. Throughout this book, trademarked names are used. Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark. Where such designations appear in this book, they have been printed with initial caps. Information contained in this work has been obtained by The McGraw-Hill Companies, Inc. ("McGraw-Hill") from sources believed to be reliable. However, neither McGraw- Hill nor its authors guarantees the accuracy or completeness of any information published herein and neither McGraw-Hill nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that McGraw-Hill and its authors are supplying information but are not attempting to render engineering or other professional services. If such services are required, the assistance of an appropriate professional should be sought. This book is printed on recycled, acid-free paper containing a minimum of 50 percent recycled de-inked fiber. CONTENTS CONTENTS Chapter 1 First Things First Standards Where Do They Come From? The Telecommunications Standardization Sector (TSS) The Telecommunications Standardization Bureau (TSB) The Radio Bureau The Standards Other Important Organizations The Network Network Access Network Transport The Many Flavors of Transport Transport Channels Analog versus Digital Signaling: Dispensing with Myths Digital Signaling Combining Signaling Techniques for Higher Bit Rates The Internet: What Is it? The World Wide Web Internet Timeline (1960-1997) Chapter Summary Chapter 1 Questions Chapter 2 Protocols Data Communications Systems and Functions The Science of Communications Data Communications Networks Binary Arithmetic Review Logical Layering The Willie Sutton Story Layer by Laye