Hayes AT command set

The Hayes command set, developed by Dale Heatherington and Dennis Hayes in 1981 for the Hayes Smartmodem, is a standardized command language consisting of short text strings used to control modem operations like dialing and hanging up. The command set became the industry standard for dial-up modems, with most manufacturers adopting Hayes-compatible variations, and the term "Hayes compatible" remains important in the industry as of 2018. The Hayes solution emerged as a practical alternative to earlier methods of modem control, allowing software to directly command modems without requiring separate peripheral devices or additional hardware ports.