The basic laws and methods of transmitting messages over communication channels are described. The methods of mathematical representation of messages, signals and interference, methods for generating and converting signals in electrical communication systems (channels), noise immunity and transmission telecommunication systems, methods of economical and noise-resistant coding, optimal message reception, the principles of multi-channel transmission and distribution of information in communication systems are considered, fundamentals of digital signal processing, communication system optimization issues. For university students enrolled in the specialty "Networks and Switching Systems", "Multichannel Telecommunication Systems", "Radio Communica-tion, Broadcasting and Television", as well as for bachelors in the direction of "Telecommunications".