Hayes AT command set

The Hayes command set (also known as the AT command set) is a specific <a href="/facts/Command_language/YVXavbxQ">command language</a> originally developed by <a href="/facts/Dale_Heatherington/YXL5LqyT">Dale Heatherington</a> and <a href="/facts/Dennis_Hayes_(businessman)/1o2tQP6e">Dennis Hayes</a> for the <a href="/facts/Hayes_Smartmodem/bvAwftJx">Hayes Smartmodem</a> in 1981.
The command set consists of a series of short text strings which can be combined to produce commands for operations such as dialing, hanging up, and changing the parameters of the connection. The vast majority of <a href="/facts/Dial-up_modems/9H0Xwtq0">dial-up modems</a> use the Hayes command set in numerous variations.
The command set covered only those operations supported by the earliest <a href="/facts/Bit%2fs/ppUNMmVd">300 bit/s</a> modems. When new commands were required to control additional functionality in higher speed modems, a variety of one-off standards emerged from each of the major vendors. These continued to share the basic command structure and syntax, but added any number of new commands using some sort of prefix character – & for Hayes and <a href="/facts/USRobotics/Nwaocofx">USRobotics</a>, and \ for <a href="/facts/Microcom/MEJw3aV1">Microcom</a>, for instance. Many of these were re-standardized on the Hayes extensions after the introduction of the <a href="/facts/SupraFAXModem_14400/2pWJSp6e">SupraFAXModem 14400</a> and the market consolidation that followed.
The term "Hayes compatible" was and as of 2018<a href="https://en.wikipedia.org/w/index.php?title=Hayes_AT_command_set&action=edit">[update]</a> still is important within the industry.

Hayes AT command set open-in-new

Hayes AT command set