This chapter provides a comprehensive analysis of the accuracy, integrity, and availability of information across different stages of data processing, storage, and transmission. Emphasizing the concepts of information fidelity and noise immunity in data transmission systems, it explores both discrete and continuous communication channels, and delves into related topics such as coding, modulation, and the overall structure of these systems. The study offers detailed insights into the purpose and functioning of various system elements, including information sources, coders, modulators, communication channels, and demodulators. Key discussions involve the characteristics and classifications of information channels like mechanical, hydraulic, pneumatic, acoustic, optical, electrical, and radio. The paper elaborates on transmission efficiency, signal capacity, channel capacity, and the importance of frequency matching. Special attention is given to the effects of interference, signal encoding and decoding, and statistical criteria for signal detection and recognition under interference conditions. The research integrates K. Shannon's theorem on channel capacity, examines the dynamics of digital signal transmission, and evaluates the impact of interference on channel performance. Techniques for optimizing signal-to-noise ratios, such as the correlation method and matched filtering, are highlighted. Methods for channel separation in multichannel transmission networks are also discussed, including spatial, frequency, and code distribution techniques. Overall, this paper provides vital insights into enhancing data transmission efficacy and reliability, making it a valuable resource for researchers and engineers in the fields of signal processing and communication systems.