Hayes-Compatible Modem


The term Hayes-Compatible Modem refers to a modem that follows the Hayes Command Set, a standardized set of commands initially developed for the Hayes Smartmodem 300 in the early 1980s. These commands enable communication and control of various modem functions, like dialing, hanging up, or setting configurations. Being Hayes-compatible allows a modem to be easily used with various computer systems and communication software without the need for unique programming for each system.


Here’s the phonetic transcription of the keyword “Hayes-Compatible Modem”:/ˈheɪz kəmˈpætɪbəl ˈmoʊdəm/

Key Takeaways

  1. Hayes-Compatible Modems follow a standard command set, known as the Hayes command set or AT command set, which was established by Hayes Microcomputer Products for controlling dial-up modems.
  2. Compatibility with the Hayes command set allows seamless interaction between different modems and software applications, making it easier for users to connect to various online services and networks.
  3. Hayes-Compatible Modems have largely been superseded by broadband technologies such as DSL and cable modems, but they still remain useful for certain applications, like remote equipment management and legacy systems support.


The term “Hayes-Compatible Modem” refers to modems that are designed to be compatible with the command set and communication protocols initially introduced by the Hayes Smartmodem in the early 1980s.

The Hayes Smartmodem revolutionized the way computers communicated over telephone lines, as it introduced the AT (Attention) command set, which made it possible for computers to control modems with simple text commands, enabling them to dial, answer calls, and establish data connections with little human intervention.

Since the Hayes Smartmodem was widely adopted in its time, other modem manufacturers built their devices to be compatible with Hayes’ command set, making it easy for users to switch between different modems without the need to alter software compatible with this industry standard.

The term “Hayes-Compatible Modem” thus signifies the importance of a unified communication standard that greatly simplified modem use and fostered the growth of early computer networks and the internet.


Hayes-compatible modems were pivotal for enabling communication between personal computers and remote systems via telephone lines during the rise of computing in the 1980s and 1990s. The Hayes command set, originally developed by the Hayes Microcomputer Products company, served as a widely adopted language that various modem manufacturers utilized, ensuring that hardware from different sources could effectively communicate.

As a result, these modems allowed users to access remote networks and online services, participate in early-stage internet communities, and exchange data such as emails, messages, or files, proving essential for users in both personal and professional capacities. Despite their technological obsolescence, Hayes-compatible modems represented a crucial stride in the evolution of digital communication.

By standardizing modem functionality, these devices not only enjoyed considerable commercial success but also paved the way for the future development of wired and wireless networking technologies. As a direct outcome of their ubiquitous compatibility, a thriving market in modem-based services and businesses emerged, setting the foundations for the modern internet landscape and the vast array of services we enjoy today.

The impact of the Hayes command set in creating a universal modem language has left a lasting imprint on the history of technological innovation.

Examples of Hayes-Compatible Modem

Hayes Smartmodem (1981): The Hayes Smartmodem, a 300-baud modem introduced in 1981, was the first Hayes-Compatible modem that established standard commands and a communication protocol that other manufacturers could emulate. Developed by Dennis Hayes and Dale Heatherington, it allowed computers to send and receive data over telephone lines using ASCII characters. The Hayes Smartmodem revolutionized the computer communications industry, becoming a popular modem for personal computers in the 1980s.

USRobotics Sportster Modem (1980s-1990s): The USRobotics Sportster Modem series gained commercial success due to their Hayes-Compatible command set. These modems were available in various speeds, starting from 2400 bits per second (bps) up to a top speed of 56 kbps. Their ease of use, compatibility with other devices, and reliability made them a popular choice for both personal and business users.

SupraFAXModem (1990s): The SupraFAXModem, produced by Supra Corporation, was a line of Hayes-Compatible modems that not only offered data communication but also fax services. They were available in various speeds, and some models offered voice capabilities as well. The SupraFAXModem gained popularity due to its user-friendly design and broad compatibility, making computer-based faxing more accessible to individuals and businesses.

FAQs: Hayes-Compatible Modem

1. What is a Hayes-Compatible Modem?

A Hayes-Compatible Modem is a type of communication hardware designed to adhere to the Hayes command set. Developed by Hayes Microcomputer Products, this command set defined a standard language for modems to interact with computer systems and exchange data, ensuring compatibility among various devices.

2. Why is the Hayes command set important for modem communication?

The Hayes command set effectively established a standard that enabled various modems from different manufacturers to communicate effectively with computer systems. It simplified the process of connecting and exchanging data, making it easier for users to set up communication links and expanding the reach of modem-based networking.

3. Are Hayes-Compatible Modems still in use today?

Although the Hayes command set has been largely replaced by more advanced, efficient, and versatile technologies, some Hayes-Compatible Modems may still be found in use for specific applications or in legacy systems. However, modern communication solutions such as broadband and DSL have largely superseded modem-based solutions.

4. How does a Hayes-Compatible Modem work?

A Hayes-Compatible Modem uses the Hayes command set to regulate the connection and communication process. It operates by responding to commands (also known as AT commands) sent from the computer system. These commands trigger various actions, such as establishing connections, disconnecting, configuring the modem, or managing errors. The modem then communicates with other devices using these instructions and settings.

5. What types of devices can connect to a Hayes-Compatible Modem?

Hayes-Compatible Modems can connect to a wide range of devices, including computers, fax machines, and other modems. The primary requirement is that the connecting device must support the Hayes command set for communication and exchange of data.

Related Technology Terms


  • AT Command Set
  • UART chipset
  • 8li>RS-232 Serial Interface

  • V.92 Modem Standard
  • Error Correction Protocols


Sources for More Information


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