Editing Hayes AT command set (section)

{{Short description|Command language for modems}}
{{Use mdy dates|date=October 2024}}
{{Use American English|date=October 2024}}
[[File:Hayes_300_Baud_Smartmodem_02.jpg | thumb | right | alt=refer to caption | [[Hayes 300 Baud Smartmodem]] ]]

The '''Hayes command set''' (also known as the '''AT command set''') is a specific [[command language]] originally developed by [[Dale Heatherington]] and [[Dennis Hayes (businessman)|Dennis Hayes]]<ref name=ModemKing.NYT>{{cite news  |newspaper=[[The New York Times]]
   |url=https://www.nytimes.com/1999/01/07/news/the-rise-and-fall-of-the-modem-king.html
   |quote=with a partner
   |title=The Rise and Fall of the Modem King
   |author=Victoria Shannon |date=January 7, 1999}}</ref><ref>{{cite web
|url=http://history-computer.com/ModernComputer/Basis/modem.html |author=Georgi Dalakov
|title=The Modem of Dennis Hayes and Dale Heatherington |date=January 4, 2021
|access-date=January 8, 2015
<!---now secondary source to NYTimes – need not as strong a need to tag it "Unreliable source?|date=September 2016" -->
}}</ref> for the [[Hayes Smartmodem]] 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 [[dial-up modems]] use the Hayes command set in numerous variations.

The command set covered only those operations supported by the earliest [[bit/s|{{Val|300|u=bit|up=s}}]] modems. When new commands were required to control additional functionality in higher speed modems, a variety of [[ad-hoc standard|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{{snd}} {{code|&}} for Hayes and [[USRobotics]], and {{code|\}} for [[Microcom]], for instance. Many of these were re-standardized on the Hayes extensions after the introduction of the [[SupraFAXModem 14400]] and the market consolidation that followed.

The term "''Hayes compatible''" was<ref>{{cite news  |newspaper=[[Computerworld]]
   |date=March 30, 1987  |page=61
   |title=Hayes compatible}}</ref><ref name="ModemKing.NYT" /> and {{as of|2018|lc=y}} still is important within the industry.<ref>{{cite web
      |date=June 17, 2018
      |url=https://www.ibm.com/support/pages/how-set-hayes-compatible-modem
      |title=How to Set Up a Hayes Compatible Modem|website=[[IBM]]
 }}</ref>