Abstract: This research work provides an in-depth analysis of the fire alarm system, considered as a security tool for a variety of facilities, from industrial buildings to residential premises. Two key subsystems serve as the basis for the study: the fire alarm system, which is designed to detect and report the occurrence of fire, and the intrusion alarm system, whose task is to detect attempts at illegal intrusion. For each of these subsystems, their functions and components are investigated, their mechanism of action, principles of operation, and possible implementation options are described, depending on the specific conditions and security requirements. At the same time, emphasis is placed on three types of automatic fire alarm systems: threshold, addressable and addressable-analog, each of which has its own features, advantages and disadvantages. The article goes beyond theoretical analysis and presents the results of a practical study of the three main types of fire alarm systems: wired, wireless and addressable. The study is based on a specially designed training stand, which allows you to simulate the operation of fire alarm systems in conditions as close to reality as possible. The article demonstrates the connection schemes of detectors, explains their states in the "normal" and "alarm" modes. It is noted that the currents and voltages of alarm loops in different modes were measured. Dependency diagrams of these parameters are presented, and the alarm threshold levels are measured. The research presented in the paper provides a valuable contribution to the study and optimization of alarm and fire systems, providing meaningful data for the development and testing of these systems. The paper can be useful for fire and security professionals and those interested in improving the performance of these systems.