RS-232 is not a brand but a standard for serial communication, developed by the Electronic Industries Association (EIA) in the United States. It defines the electrical and functional characteristics of interfaces for data transmission between devices. Widely used in industrial automation, telecommunications, and computer peripherals, RS-232 facilitates communication between equipment like PLCs, modems, and printers. The standard has been largely replaced by newer technologies like USB and Ethernet but remains relevant in legacy systems.