John C. McDonald – författare

Since the publication of the first edition of Fundamentals of Digital Switching in 1983, there has been substantial improvement in digital switching technology and in digital networks. Packet switching has advanced from a low-speed data-oriented switching approach into a robust broadband technology which supports services ranging from low-speed data to video. This technology has eclipsed the flexibility of circuit switching. Fiber optic cable has advanced since the first edition and has substantially changed the technology of transmission. to research in optical devices to find a still better means of This success has led switching. Digital switching systems continue to benefit from the 100-fold improvement in the capabilities of semiconductor devices which has occurred during the past decade. The chip industry forecasts a similar escalation in complexity during the next 10 years. Networks of switching systems have changed due to regulatory policy reform in many nations, including the breakup of the Bell System in the United States, the introduction of new types of carriers in Japan, competition in the United Kingdom, and a reexamination of public policy in virtually all nations. Standards bodies have been productive in specifying new capabilities for future networks involving interactive and distributive services through STM and A TM technologies.

The development of low-cost digital integrated circuits has brought digital switching from a concept to an economic reality. Digital switching systems have now found worldwide acceptance and there are very few new switch­ ing systems being considered either for design or application which are not digital. Digital technology has created new opportunities for innovation including the integration of digital transmission and switching, the combi­ nation of voice and data services in one switching entity, and the design of switching systems which are economical over a broad range of sizes. In the strict sense, the term "digital switching" refers to a system which establishes a message channel between two terminations where infor­ mation is represented in digital form. In more common usage, a digital switch usually contains a time-divided network composed of logic gates and digital memory to accomplish the switching function. The intent of this book is to provide an introductory level explanation of the principles of digital switching. These principles apply to both public and PABX switching. The book is aimed at those who apply, design, main­ tain, or simply wish to understand digital switching techniques. An electri­ cal engineering degree is definitely not required for comprehension. We have concentrated on explaining digital switching techniques without the use of detailed mathematics. However, each chapter contains a comprehen­ sive list of references which will lead the reader to sources for a more in-depth study of the many subjects covered.

Since the publication of the first edition of Fundamentals of Digital Switching in 1983, there has been substantial improvement in digital switching technology and in digital networks. Packet switching has advanced from a low-speed data-oriented switching approach into a robust broadband technology which supports services ranging from low-speed data to video. This technology has eclipsed the flexibility of circuit switching. Fiber optic cable has advanced since the first edition and has substantially changed the technology of transmission. to research in optical devices to find a still better means of This success has led switching. Digital switching systems continue to benefit from the 100-fold improvement in the capabilities of semiconductor devices which has occurred during the past decade. The chip industry forecasts a similar escalation in complexity during the next 10 years. Networks of switching systems have changed due to regulatory policy reform in many nations, including the breakup of the Bell System in the United States, the introduction of new types of carriers in Japan, competition in the United Kingdom, and a reexamination of public policy in virtually all nations. Standards bodies have been productive in specifying new capabilities for future networks involving interactive and distributive services through STM and A TM technologies.