Their competition through this period was primarily from two other high-end vendors, USRobotics and Telebit, while other companies mostly sold into niches or were strictly low-end offerings.

In the early 1990s a number of greatly cost-reduced high-performance modems were released by competitors, notably the SupraFAXModem 14400 in 1992, which eroded price points in the market.

The widespread introduction of ADSL and cable modems in the mid-1990s repeatedly drove the company in Chapter 11 protection before being liquidated in 1999.

[2] Business picked up quickly, and by January 1978 they had quit their jobs at National Data to form their own company,[1] D.C. Hayes Associates.

To comply, Micromodems were supplied their own DAA-like connector in the form of the FCC-approved "microcoupler": a small external box that connected to the internal modem card using a ribbon cable.

Not only did it require special driver software that often meant it could only be used with a single terminal emulator, but a different hardware design was needed for every computer bus, including Apple II, S-100, TRS-80, and others.

There needed to be some way to indicate that the characters flowing out from the computer to the modem were not simply additional data to be sent to the far end, but commands to be acted on.

Hayes and the company's marketing manager Glenn Sirkis approached Heatherington with an outline for a new command-driven external modem.

Several solutions to the command problem were studied, and in the end, Heatherington decided the only practical one was to have the modem operate in two modes.

With the basic idea outlined, Hayes and Sirkis gave Heatherington the go-ahead to build a prototype by adding a microcontroller to an otherwise lightly modified version of their existing 300 bit/s hardware.

Hayes added a requirement of his own, that the modem be able to automatically detect what speed the computer's serial port was set to when first powered on.

Heatherington eventually suggested the use of a well-known character sequence for this purpose, recommending AT for "attention", which is prefixed on all commands.

The new design, housed in an extruded aluminum case sized to allow a standard desktop telephone to rest on top, was announced in April 1981.

[5] The Hayes Stack Chronograph, an external real-time clock and the Transet 1000, a printer buffer and primitive email box.

At that price point, Hayes could build a "Cadillac of modems", using high-quality components, an extruded aluminum case, and an acrylic front panel with a number of LED indicators.

However, this was only a limited competitive advantage, since it was not long before companies offering Hayes "clones" introduced derivative 1200 bit/s models of their own.

[13] Competitors derisively termed it the "modem tax", and a number of manufacturers banded together and introduced the Time Independent Escape Sequence, or TIES, but it was not as robust as Heatherington's system and never became very successful.

They were also expensive and found mostly in professional settings, notably for Unix-running minicomputers for UUCP use where their protocol spoofing offered further speed improvements.

USR's designs were simpler than Telebits and ran at "only" 9,600 bit/s, but carved out a strong niche by offering deep discounts to sysops.

In order to set up the modem to accept or reject certain types of connections, Hayes had added a number of new commands prefixed by & (the ampersand) to the Smartmodem 2400.

In 1990 the company introduced the Smartmodem Ultra 96, which offered both V.32 and Express 96 support, and added the new V.42bis error correction and compression system (in addition to MNP).

Hayes eventually purchased two of their competitors, Practical Peripherals and Cardinal Technologies, turning them into low-cost brands in order to compete with a flood of companies like Supra Corporation and Zoom Telephonics.

Oddly it was the Rockwell chipset that also re-standardized the various command sets back on the original high-speed ones introduced by Hayes.

As the Rockwell-based systems became more and more common, other companies, like AT&T, introduced new versions of their modem chip sets with identical commands.

Hayes realized that changes in the telephone networks would eventually render the modem, in its current form, obsolete.

Their attention turned to Asymmetric Digital Subscriber Line (ADSL), which ran over the existing wiring and did not block a telephone connection in the process.

The end-user was offered much higher speeds while still being able to use existing phones, with the added "benefit" of helping tie the user to the telephone company's own ISP.

In an attempt at diversification in January 1991 it had acquired most of the assets of local area network software developer Waterloo Microsystems Inc of Waterloo, Ontario and belatedly entered the operating system (OS) market in June 1991 with LANstep, a network OS for small offices, but this was subsequently abandoned in 1994 in the face of stiff competition particularly from Novell NetWare.

They entered Chapter 11 protection in November 1994,[16] exiting in October 1995 as Hayes Corp. after selling 49%[17] of the company to Nortel and a Singapore-based venture capital firm.

In 1997 they merged with Access Beyond, a builder of ISP rack-mount modems and terminal servers, and changed the company name again, this time to Hayes Communications.