RS-232 - introduction RS-232 is a standard for serial data communication first defined in 1962 by the Electronic Industries Alliance for use with data communication devices such as teletypewriters. Later, personal computers and other devices made use of the RS-232 standard for connection to peripheral devices such as modems, mice, keyboards, etc. In recent years RS-232 has become increasingly displaced by USB in modern PCs, though the standard, and many variants, are still widely used in industrial machines, networking equipment and scientific instruments. More information on RS-232 serial protocol decoding >>