Hayes Microcomputer Products

Hayes Microcomputer Products

Hayes Microcomputer Products was a U.S.-based manufacturer of modems. They are particularly well known for their Smartmodem, which introduced the ability to control the modem through commands sent in the data stream itself. The "smart modem" approach dramatically simplified operation, making modems a practical device for a much wider audience. Today almost all modems still use a variant of the Hayes command set introduced in the Smartmodem.

Early History

Dennis C. Hayes left the Georgia Institute of Technology in the mid-1970s to work at an early data communications company, National Data Corp, a company that handled electronic money transfers and credit card authorizations. Hayes' job was to set up modem connections for NDC's customers.

At the time, modems generally came in two "flavors", one for the end-user that required the user to dial the phone manually and use an acoustic coupler for connection, and another dedicated to answering incoming calls that was intended for use on the minicomputer or mainframe the user was calling. No single modem offered all of these features, at least not at a price-point that would be attractive to non-business users.

Hayes was a computer hobbyist, and felt that modems would be highly compelling to users of what would soon be known as home computers. However, existing modems were simply too expensive and difficult to use to be practical for most users. What was needed was a single modem that could "do it all"; connect directly to the phone, answer incoming calls, dial numbers to initiate outgoing calls and hang up when the call was complete.

The main problem with producing such a modem was forwarding commands from the computer. This could be addressed in internal modems that plugged directly into the computer's motherboard. Such modems had access to the computer's main memory, and by dedicating certain memory locations (or registers) to various status readouts or commands, software programs running on the computer could control the modem. This was a straightforward and thus a popular solution; the Novation APPLE-CAT II for the Apple II computer was an early programmable modem of this type.

Hayes started producing similar products at a "hobby level" in his kitchen in April 1977 with his friend and co-worker, Dale Heatherington. Their first product was the 80-103A, a 300 bit/s Bell 103-compatible design for S-100 bus machines. Business picked up quickly, and in January 1978 they quit their jobs at National Data to form their own company, D.C. Hayes Associates.

Sales were further improved in early 1979 with the introduction of the Micromodem II, a similar 300 bit/s design for the Apple II that used an external "microcoupler" to connect to telephone lines. In 1980 the company changed its name to Hayes Microcomputer Products, under which it operated for most of its history.

The Smartmodem

Although powerful, the internal modem was commercially impractical. Not only did it require special driver software, but a different hardware design was needed for every computer bus, including Apple II, S-100, TRS-80, and others. Some popular computers, like the Atari 400, did not even integrate internal slots. An obvious solution was to use the RS-232 serial port; modems were serial devices and generally driven off RS-232 anyway, and most computer designs included an RS-232 port, or some variant.

Hayes and the company's marketing manager, Glenn Sirkis, approached Heatherington with an outline for a new command-driven external modem. A few external modems already offered the ability to dial the phone by entering a phone number when the modem was first started, but the real problem was somehow sending a command to hang up, "while" the modem was already connected. 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.

Several solutions to the problem were studied, and in the end Heatherington decided the only practical one was to have the modem operate in two modes. In one, "data mode", all data forwarded from the computer was modulated and sent over the connected telephone line as it was with any other modem. In the other, "command mode", data forwarded from the computer was instead interpreted as commands. In this way, the modem could be instructed by the computer to perform various operations, such as hang up the phone or dial a number. The modem would normally start up in command mode.

The problem was how to move from mode to mode. One option would be to signal this change — "put yourself into command mode" — via one of the many pins in the RS-232 cable. However, while the 25-pin connector on the modem side had more than enough pins for this purpose (even some "meant" for this purpose), the computer side often used a much smaller 9-pin connector, and equally often many of these pins weren't actually connected or accessible from software. In fact, there were very few pins that were guaranteed to work on all computers, mostly the data in and out, "ready" indications that said whether the modem or computer was operational, and "sometimes" flow-control pins.

While it would have been possible to use some of these pins for the sort of command-switching they needed (the "ready" indications, for example, would have sufficed) Heatherington instead came up with the idea of using a rarely-seen sequence of characters for this duty. Since these characters could be sent to the modem using the same two data pins that the port would need anyway, they could be sure that such a system would work on every computer.

The sequence he decided on was +++ (three plus signs). When this was received from the computer, the modem would switch from data to command mode. Of course it was entirely possible that the computer would send this sequence for other reasons, for example, the sequence might be contained within a text file describing how modems worked. In order to filter out these "accidental" sequences, Heatherington's design only switched to command mode if the sequence was led and followed by a one-second pause, the "guard time", in which no other data was sent. In this case it could be safely assumed that the sequence was being sent deliberately by a user, as opposed to being buried in the middle of a stream of data.

With the basic idea outlined, Hayes and Sirkis gave Heatherington the go-ahead to built a prototype by adding a microcontroller to an otherwise lightly-modified version of their existing 300 bit/s hardware. Sirkis was particularly interested in using the 1 MHz PIC microcontroller, which were available for only US$1 a piece. After six months of trying to get the modem working with the PIC, Heatherington gave up and demanded they use the 8 MHz Zilog Z8 instead, a US$10 part. Sirkis acquiesced, and a working prototype was soon complete.

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. This was not simple unless the modem "knew" what data was initially being sent, allowing it to time the bits and thereby guess the speed. 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 released in July 1981. It was known simply as the Smartmodem. The Smartmodem was the first modem integrating complete control over the phone line, and that allowed it to be used in exactly the same fashion with any computer.

Hayes originally had big plans for the form factor, referring to it as the Hayes Stack and intending to release a range of products that could be stacked beside the computer. In the end, the only non-modem device to be added to the line was the Hayes Stack Chronograph, an external real-time clock whose sales were apparently dismal. [ [http://incolor.inebraska.com/bill_r/hayes_stack_chronograph.htm The Hayes Stack Chronograph] ] Early advertising referred to the Smartmodem as the "Hayes Stack Smartmodem", [ [http://www.aresluna.org/attached/computerhistory/ads/international/hayes/pics/percon8202 Hayes Smartmodem advertisement from Personal Computing 2/82] ] but this naming convention was dropped a short time later.

At the time of its introduction, the modem market was fairly small, and competitors generally ignored the Smartmodem. But it was not long before hobbyists were able to combine the Smartmodem with new software to create the first real bulletin board systems (BBSes), which created significant market demand. The market grew rapidly in the mid-80's, and as the Smartmodem was the only truly "universal" modem on the market, Hayes grew to take over much of the market. Heatherington retired from what was then a large company in 1984.


The modem market in the 1970's was very simple and stagnant. Modems tended to sell at US$1 per baud. Hayes saw no need to be different — the original Hayes 300 baud modem sold for US$299 retail. At that price point, Hayes could build a "Cadillac of modems", using high-quality components, an extruded aluminum case, and a plexiglas front panel with a number of LED indicators.

As the modem market expanded, competitors quickly copied the Hayes command set and often the Hayes industrial design as well. But in order to compete with Hayes on price, early competitors manufactured modems using low-cost components that were often unreliable. Hayes quickly gained a reputation for high quality, and for a period of time held a 50% market share.

Also differentiating Hayes from its competition was the Smartmodem's use of the guard time. Hayes had patented this concept in 1985 in patent #4,549,302, the "Modem With Improved Escape Sequence With Guard Time Mechanism", generally referred to as the "Hayes '302 patent". Hayes licensed the guard time to other manufacturers for $1 a modem – a charge which competitors derisively termed the "modem tax". 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.

In 1982, at the Spring Comdex in Atlantic City, Hayes introduced the Bell 212-compatible Smartmodem 1200 for $699, the first practical all-in-one 1200 bit/s Bell 212-compatible modem. The earlier design was redesignated the Smartmodem 300. At the time, Hayes was one of the few modem companies with the capital and engineering wherewithal to develop entirely new modem architectures. 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.

The 1200 bit/s market existed for a relatively short time; in 1984 the CCITT introduced the v.22bis standard for 2400 bit/s operation. This was the first time that the CCITT's standard predated Bell's introductions, avoiding compatibility issues that had plagued earlier standards. Modem companies quickly incorporated v.22bis into their product lines. Hayes was no exception; the company introduced its v.22bis Smartmodem 2400 at US$549 in 1985 (the 1200 bit/s Smartmodem also remained available at a lower price point). Competition drove prices rapidly downward, and by 1987 a clone 2400 bit/s modem was generally available for around US$250. After 1987, modems increasingly became a commodity item.

Higher speeds and increased competition

Hayes was not as fast as some other manufacturers to release modems that ran faster than 2400 bit/s, which opened the door for U.S. Robotics (USR) and Telebit to meet market demand with faster products. In 1987 Hayes responded with the 9600 bit/s "Ping-Pong" protocol, which was later renamed "Express 96". The name referred to the way the modems could "ping-pong" the single high-speed link between the two ends on demand, in a fashion similar to the USR and Telebit protocols. However, Express 96 was both late-to-market and lacked error correction, making it far less attractive than its competition. The design was generally unsuccessful, and for the first time Hayes lost cachet as the leader in modem design and manufacture.

Hayes's slow entry into the high-speed market led to a fracturing of the command set. 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. When they moved to the Smartmodem 9600, they simply extended the set further, using the same syntax. The other companies involved all used their own syntax; USR used an incompatible set of &-prefixed commands, Microcom used , and Telebit was based on setting a series of registers. All of these survived for some time into the early 1990s.

Through the late 1980s and early 1990s, new standard high-speed modes were introduced by the CCITT. The first of these, v.32, offered 9600 bit/s in both directions at the same time, whereas earlier high-speed protocols were high-speed in one direction only. In 1988 Hayes effectively abandoned their Express 96 protocol in favor of v.32, which along with MNP support was built into the US$1199 Hayes V-series Smartmodem 9600. 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). v.32 modems remained fairly rare and expensive, although by 1990 third-party v.32 modems were available for approximately US$600.


In 1991, Rockwell introduced a low-cost chipset supporting the new 14,400 bit/s v.32bis standard, along with similar v.32 and v.22bis (2400 bit/s) versions, all of which supported MNP, v.42bis and, optionally, 9600 bit/s v.29 fax modem capabilities. Their system was introduced commercially in the SupraFAXModem 14400, which went on to become a runaway bestseller. Soon there were literally hundreds of similar models on the market, and Rockwell's competitors also rushed in with similar chipsets of their own.

Hayes was never able to re-establish itself as a market leader through this era. They quickly introduced their own v.32bis model in the fall of 1991, the US$799 Smartmodem Ultra 144, but this point Express 96 had little caché, and the market was already flooded with lower-cost modems. They then split their line into the Accura and Optima brands, offering the Accura as a low-cost model, although the feature sets were not that different between the two lines. Hayes eventually purchased two of their competitors, Practical Peripherals and Cardinal, turning them into low-cost brands in order to compete with companies such as Zoom Telephonics.

As speeds increased with the introduction of v.34 and v.90, Hayes increasingly became a follower rather than a leader. By the mid-1990s their modems were also based on the Rockwell chip set, and had little to distinguish themselves from other vendors.

Oddly it was the Rockwell chip set 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. Rockwell had taken their commands from the V-series Smartmodems, so by the mid-90s the market was once again based largely on a "real" Hayes command set.

Decline and fall

Hayes realized that changes in the telephone networks would eventually render the modem, in its current form, obsolete. As early as 1985 he started efforts to produce consumer-ready ISDN "modems", betting the company on ISDN becoming a widespread standard — which was widely believed at the time. By the early 1990s, this was a major focus of the company.

However, ISDN simply never happened. The whole model was based on end-to-end digital communications, and was thus limited to the speed of the long-distance carrier lines, either 56 or 64 kbit/s. The Bell companies were interested in deploying ISDN, but doing so required customer-end installations to make their conventional telephones work, which made the system unattractive for wide-scale deployment.

Additionally, the rise of the Internet in the mid-1990s made point-to-point communications far less interesting. After dialing their local Internet service provider, the user could "call out" at high speed to services around the world, so the need for long-distance data calls was generally eliminated. As a result of this shift, there was no real need to limit the user to the speed of the long-distance lines, giving the Bell companies flexibility in terms of what to install at the user's site. Their attention turned to ADSL, which ran over the existing wiring and did not use up a phone line in the process. The end-user was offered much higher speeds while still being able to use their existing phones, with the added "benefit" of helping tie the user to the telephone company's own ISP.

Hayes, having bet the company on a system that was never actually deployed, had no new products in the pipeline. An effort was started to move into the market for ADSL and cable modems, but this was a multi-year effort during a period when USR increasingly took over the market. They entered Chapter 11 protection in November 1994, exiting in October 1995 as Hayes Corp. after selling 49% 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. The merger was primarily a way to take the company public. The stock started crashing over the next year, from around US$12 in early 1998 to pennies in October, when they once again filed for Chapter 11 protection. No new funding could be found, and in 1999 the company assets were liquidated.

The brand name was purchased and revived by onetime rival Zoom Technologies in July 1999. Zoom continues to use the Hayes name on some of their products.


A widely circulated history of computing states that the Smartmodem 1200 was introduced in 1981. This "history" is confusing the Smartmodem 1200 with the original Smartmodem. Another confuses the original Smartmodem 9600 with the later V-Series modems, reversing the introduction dates and features.


* [http://timeline.textfiles.com/1977/ The Rise and Fall of the Modem King]

External links

* [http://www.heatherington.net/hayes/index.html Hayes Photo Album]
* [http://www.aresluna.org/attached/computerhistory/ads/international/hayes Hayes Advertising]

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