The originator of the de facto standard for modems in the world of microcomputers was Hayes Microcomputer Products, Inc. In 1981, the company produced the first modem to operate with a command set. The set of commands that is used to control the operation of a modem is called the standard Hayes AT Command Set. Most of the commands are prefaced with an AT which stands for ATtention. Today, the term Hayes-compatible is used as an adjective to describe modems from other manufacturers that operate with the same command set as the popular Hayes modems.
The standard for controlling signals from a computer for use by a modem that will communicate with most telecommunications software.
Hayes Microcomputer Products is one of the leading manufacturers of modems and has developed a language called the AT command set for controlling modems that has become the de facto standard. Any modem that recognizes Hayes modem commands is said to be Hayes-compatible. This is very useful because most communications programs use Hayes modem commands. Virtually all modems manufactured today are Hayes-compatible.