Digital Telephony

What is "digital telephony"? To the authors, the term digital telephony de notes the technology used to provide a completely digital point-to-point voice communication system from end to end. This implies the use of digital technol ogy from one end instrument through the transmission facilities and switching centers to another end instrument. Digital telephony has become possible only because of the recent and ongoing surge of semiconductor developments allowing microminiaturization and high reliability along with reduced costs. This book deals with both the future and the present. Thus, the first chapter is entitled, "A Network in Transition." As baselines, Chapters 2, 3, and 10 provide the reader with the present status of telephone technology in terms of voice digitization as well as switching principles. The book is an outgrowth of the authors' continuing engineering education course, "Digital Telephony," which they have taught since January, 1980, to attendees from business, industry, government, common carriers, and tele phony equipment manufacturers. These attendees come from a wide variety of educational backgrounds. but generally have the equivalent of at least a bachelor's degree in electrical engineering. The book has been written to provide both the engineering student and the practicing engineer a working knowledge of the principles of present and future voice communication systems based upon the use of the public switched network. Problems or discussion questions have been included at the ends of the chapters to facilitate the book's use as a senior level or first year graduate level course text.

What is "digital telephony"? To the authors, the term digital telephony denotes the technology used to provide a completely digital telecommunication system from end-to-end. This implies the use of digital technology from one end instru ment through transmission facilities and switching centers to another end instru ment. Digital telephony has become possible only because of the recent and on going surge of semiconductor developments, allowing microminiaturization and high reliability along with reduced costs. This book deals with both the future and the present. Thus, the first chapter is entitled, "A Network in Transition." As baselines, Chapters 2 and 11 provide the reader with the present status of teler-hone technology in terms of voice digiti zation as well as switching principles. The book is an outgrowth of the authors' consulting and teaching experience in the field since the early 1980s. The book has been written to provide both the engineering student and the practicing engineer a working knowledge of the prin ciples of present and future telecommunication systems based upon the use of the public switched network. Problems or discussion questions have been included at the ends of the chapters to facilitate the book's use as a senior-level or first year graduate-level course text. Numerous clients and associates of the authors as well as hundreds of others have provided useful information and examples for the text, and the authors wish to thank all those who have so contributed either directly or indirectly.

An introduction to the new digital techniques of telephone communication networks, with emphasis on voice applications: voice digitization, digital transmission, digital switching, network synchronization, network control, and network analysis. Presents basic theory and stresses the application and operational aspects of communication systems design. Relates system level design considerations to telephone networks around the world, particularly in North America.

Introduces all aspects of digital communications, emphasizing voice applications and digitization, digital transmission and switching, network synchronization, control and analysis. Non-technical in the traditional (analytical) sense of communications theory, it stresses the application and operational aspects of communications and system design. Topical discussions in this Second Edition explore new terminology, the advantages and disadvantages of using digital voice networks, the functions and uses of digital radio and fiber optical transmission systems and an analysis of traffic patterns in the digital communications network. New equations and traffic tables, a revised glossary of terms, an up-to-date bibliography and an expanded index enhance and complete this book.

Design a complete VoIP or analog PBX with Asterisk, even if you have no previous Asterisk experience and only basic telecommunications knowledge. This bestselling guide makes it easy, with a detailed roadmap to installing, configuring, and integrating this open source software into your existing phone system. Ideal for Linux administrators, developers, and power users, this book shows you how to write a basic dialplan step by step, and quickly brings you up to speed on the latest Asterisk features in version 1.8. Integrate Asterisk with analog, VoIP, and digital telephony systems Build a simple interactive dialplan, and dive into advanced concepts Use Asterisk’s voicemail options—including a standalone voicemail server Build a menuing system and add applications that act on caller input Incorporate a relational database with MySQL and Postgre SQL Connect to external services such as LDAP, calendars, XMPP, and Skype Use Automatic Call Distribution to build a call queuing system Learn how to use Asterisk’s security, call routing, and faxing features