No matter how you feel about ISDN, some companies have it and some telephone customers are moving to it. This book is not a manual on how to implement an ISDN, nor is it a detailed description of the lowest level ISDN functionality. Instead, it is a moderately technical overview of ISDN.

The book covers many ISDN concepts that may interest the reader. Chapter 1 gives a brief history of telephony and digital transmission. Chapters 2, 3, 4, and 7 discuss many of ISDN’s physical characteristics. Chapters 5 and 6 describe the basic rate interface (BRI) and primary rate interface (PRI). Chapter 8 covers customer premises equipment (CPE). Finally, chapter 9 introduces broadband ISDN (BISDN).

Even though ISDN represents the integration of voice and data on a single transmission line, the reader should note that this work is not an introduction to telephony and data communications concepts. It only covers ISDN material and does not compare or contrast any other communications methods.

In a recent article [1], Smalley and Donohue suggest that ISDN has been too long in coming and that heavy data communications users will get better performance from T1. They note, however, that ISDN does have some advantages, namely integrated voice and data and the use of existing twisted pair media. Potential ISDN customers should do a lot of research before purchasing any data communications service. Do not rely on this book as the definitive source of ISDN information.