A SISO system, or Single Input Single Output system, is a type of control system that has one input and one output. This means that the system takes a single signal or command and produces a single response or result. SISO systems are commonly used in various applications, such as in automotive control systems and industrial processes, where simplicity and clarity are essential. In a SISO system, the relationship between the input and output can be analyzed using mathematical models, often represented in the Laplace domain. This allows engineers to design and optimize the system for desired performance, such as stability and responsiveness. SISO systems are fundamental in control theory and serve as a building block for more complex systems, like MIMO (Multiple Input Multiple Output) systems.