A review of various types of audioinformation leakage channels existing in a telephone network as well as possible ways and means for its protection are given in this book. The information covering a broad nomenclature of both pickup and protection means is considered. In the second edition the additional materials concerning feedback channels of interactive transmission systems are given.
The book is intended for researchers and engineers whose activity is connected with the necessity of protection of information. It may be used as a handbook for studying the following disciplines as "Protection of information", "The principles of protection of information" and "Provision of technical means of protection of information" in the universities, colleges and the institutes of development of vocational competence.