I/O modules, or Input/Output modules, are essential components in industrial automation systems, produced by various manufacturers worldwide. These modules are typically associated with brands like Allen-Bradley (USA, Rockwell Automation), Siemens (Germany), Schneider Electric (France), and Omron (Japan). They serve industries such as manufacturing, energy, and process control by facilitating communication between sensors, actuators, and programmable logic controllers (PLCs). Key products include digital I/O modules, analog I/O modules, and communication interfaces, designed for reliability and scalability in harsh industrial environments. Companies like Radwell and Grainger distribute these modules alongside other industrial automation components.