Safe input/output modules are a category of industrial automation products designed to ensure secure and reliable signal transmission in harsh environments. These modules are offered by various global brands, including Siemens (Germany), Rockwell Automation (USA), and Phoenix Contact (Germany). They serve industries such as manufacturing, oil & gas, and energy, providing isolation, surge protection, and fault detection for digital/analog signals. Key products include safe digital input modules, fail-safe output modules, and intrinsically safe barriers, complying with international safety standards like IEC 61508 and ATEX.