From the reviews of the Second Edition "The book stresses how systems operate and the rationale behind their design, rather than presenting rigorous analytical formulations [It provides] the practicality and breadth essential to mastering the concepts of modern communications systems." - Telecommunication Journal In this expanded new edition of his bestselling book, telephony expert John Bellamy continues to provide telecommunications engineers with practical, comprehensive coverage of all aspects of digital telephone systems, while addressing the rapid changes the field has seen in recent years. Bellamy discusses the near-complete conversion to digital technology in telephone networks worldwide, examines both existing and emerging technologies, and explores the intricacies of carrying voice over data networks as well as the use of telephone networks for carrying data for Internet access. He emphasizes system design, implementation, and application, but also correlates the practice to communications theory. With 30 percent new material, Digital Telephony, Third Edition features:Clear explanations on how to overcome problems associated with the replacement of old analog technology with new digital technologyA new chapter on digital mobile telephone technologyNew material on how, data networks support voice communicationA new chapter on digital subscriber access technologiesMore than 300 graphs illustrating conceptsExamples from the U.S. network as well as ITU public telephone networks