Digital Telephony and Network Integration

Abstract

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. 1 A Network in Transition -- 1.1 Introduction -- 1.2 The Network Yesterday -- 1.3 The Network Today -- 1.4 The Network Tomorrow -- 2 Speech Digitization Fundamentals -- 2.1 Introduction -- 2.2 Speech Coding Approaches -- 2.3 Sampling -- 2.4 Quantization -- 2.5 Effect of Digitization on Bandwidth -- 2.6 Speech Digitizer Performance -- 2.7 Speech Coding Advantages -- 3 Pulse Code Modulation -- 3.1 Introduction -- 3.2 Basic PCM Encoding -- 3.3 Compression and Nonuniform Quantization -- 3.4 PCM Performance -- 4 Efficient Speech Coding Techniques -- 4.1 Introduction -- 4.2 Special PCM Techniques -- 4.3 Differential PCM -- 4.4 Delta Modulation (DM) -- 4.5 Subband Coding (SBC) -- 4.6 Adaptive Predictive Coding (APC) -- 4.7 Adaptive Transform Coding (ATC) -- 4.8 Vocoders -- 4.9 Hybrid (Waveform-Parametric) Techniques -- 4.10 Performance -- 5 Digital Techniques in the Telephone Network -- 5.1 Introduction -- 5.2 Synchronization -- 5.3 Time-Division Multiplexing -- 5.4 Error Coders -- 5.5 Scramblers -- 5.6 Channel Coders -- 5.7 Signal Impairments in Transmission -- 5.8 Signaling and Supervision -- 5.9 Monitoring and Maintenance -- 5.10 Digital Speech Interpolation -- 5.11 Digital Repeaters -- 5.12 Digitization of the Loop Plant -- 5.13 Speech Recognition -- 5.14 Computer Voice Response -- 6 Digital Transmission -- 6.1 Introduction -- 6.2 Digital Modulation Techniques -- 6.3 T-Carrier Systems -- 6.4 The Digital Hierarchy -- 6.5 Multiplexing -- 6.6 Error Control -- 6.7 Pair-Gain Systems -- 6.8 Retrofit -- 6.9 Testing and Fault Detection -- 7 Microwave Transmission -- 7.1 Introduction -- 7.2 Characteristics of Microwave Propagation -- 7.3 Microwave System Engineering -- 7.4 Characteristics of Microwave Equipment -- 7.5 Digital Microwave Radio Systems -- 8 Satellite Transmission -- 8.1 Introduction -- 8.2 Characteristics of Satellite Propagation -- 8.3 Satellite System Design -- 8.4 Characteristics of Satellite System Equipment -- 8.5 Major Operational Communication Satellite Systems -- 8.6 Future Trends in Communication Satellite Systems -- 9 Fiber Optic Transmission -- 9.1 Introduction -- 9.2 Fiber Transmission Characteristics -- 9.3 Fiber Types -- 9.4 Optical Sources -- 9.5 Photodetectors -- 9.6 Coupling of Sources to Fibers -- 9.7 Repeaters and Couplers -- 9.8 Noise Sources -- 9.9 Operational and Planned Fiber Optic Systems -- 9.10 Wavelength Division Multiplexing -- 9.11 Future Optical Telephone Network -- 10 The Circuit Switching Environment -- 10.1 Introduction -- 10.2 Basic Switching Functions -- 10.3 Basic Switching System -- 10.4 Control Concepts -- 10.5 Signaling -- 10.6 Switching Network Technology -- 10.7 Why Digital Switching? -- 11 Digital Switching Architecture -- 11.1 Introduction -- 11.2 Terminal Interface Techniques -- 11.3 Switching Network Considerations -- 11.4 Service Circuit Techniques -- 11.5 Control Architectures -- 11.6 Maintenance Diagnostics and Administration -- 12 Operational Switching Systems -- 12.1 Introduction -- 12.2 Rockwell 580 DSS -- 12.3 Stromberg-Carlson System Century DCO -- 12.4 Northern Telecom DMS-100 -- 12.5 GTE GTD-5 EAX -- 12.6 AT & T No. 5 ESS -- 12.7 ITT System 1240 -- 12.8 GTE GTD-3 EAX -- 12.9 AT & T No. 4 ESS -- 13 Evolution of the Switched Digital Network -- 13.1 Introduction -- 13.2 The North American Analog Network -- 13.3 The Evolving Digital Network -- 13.4 Intra-LATA Networks -- 14 Evolution of the Integrated Services Digital Network (ISDN) -- 14.1 The ISDN Concept -- 14.2 ISDN Plans and Progress -- 14.3 Future Trends and Issues.