The monograph "Evolution of Telecommunication Protocols" is devoted to a wide range of questions related to signaling protocols in telephone networks of former USSR Public Switched Telephone Networks. . .The SDL-oriented analysis method enabling the description in a relatively simple way of the specifics of interoffice signaling systems and call handling procedures, as well as specifications and scenarios required for designing is discussed. The evolution of Russian interoffice signaling systems, from three-wire trunks and so called "R 1.5" to Signaling System No.7 protocols is considered. All engineering solutions are directed toward up-to-date digital switching nodes and exchanges. . .The book is primarily intended for engineers and scientists involved in the research, development, and operation of switching nodes. The book will be a valuable reference source for students and postgraduates studying in these areas. .