The History of the Modem

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The modem has been around a lot longer than most people realize.

Modems are one of the most common computing devices, but they’ve changed a lot over the years. Most people don’t think about the history of these devices, but the humble modem has a long and colorful history.

Project SAGE

Like a lot of modern computing technology, the modem is a product of the Cold War. Project SAGE (Semi-Automatic Ground Environment) was an early computer network attempting to create an advanced radar system to detect an incoming Soviet attack. Project SAGE was itself a revolutionary project, prefiguring the graphical user interface by a number of years, but AT&T contributed the first known use of the term "modem," with devices that communicated with the computer over phone lines. The term "modem" is a portmanteau of "modulator" and "demodulator." The modulator turns the digital 1s and 0s of computer data into analog noises that can be transmitted over phone lines, and the demodulator turns the noises back into 1s and 0s that the computer at the other end can understand. The advantage of these devices was that they could connect terminals and computers over cheaper regular phone lines instead of expensive leased lines. (Not that phone calls back in those days were especially cheap. Back in the days of the pre-breakup AT&T, long-distance calls could be expensive.)

Acoustic Couplers and Court Cases

The earliest modems were known as "acoustic couplers." You might have seen one used in the movie "War Games" to hack into NORAD. The handset sits in a cradle while the modem sends and receives data using the phone itself. This design was a byproduct of AT&T’s legal monopoly of the U.S. phone system. They owned the wires, the service, even the phones themselves. Connecting a device directly to the phone lines was called "attaching a foreign device," and was strictly prohibited by law. The phones were also hard-wired into the wall connector. The standardized phone jacks that are common today simply didn’t exist.

A court case, Hush-a-Phone v. United States, was an important verdict that affected the way early modems worked. The Hush-a-Phone was a device that clipped onto a phone handset to reduce the ability for other people to overhear a phone conversation. AT&T objected to it, but the D.C. Circuit Court of Appeals found that devices that didn’t actually connect to the phone company’s wiring were permissible. While a device that connected directly to the phone system would have been illegal, an acoustic coupler was perfectly fine, since it didn’t affect the phone line at all.

In 1968, Carter v. AT&T Corp. affected modem design as well, although it took some years for it to become apparent. The Carterfone was a device that connected CB radio to the phone system. Even though it was acoustically coupled, AT&T tried to put the kibosh on this one as well. The FCC allowed that customers could attach any device to their phones as long as they didn’t interfere with the operation of the phone system. This launched a whole market of third-party devices, including answering machines, fax machines and, of course, modems. The arrival of the personal computer created a market for modems, but it took a "killer app" to create demand.

Bulletin Board

For many people in the 80s and early 90s, the primary reason to get a modem was to access Bulletin Board Systems (BBS). While it’s fashionable these days to describe past online media as the precursor to social networking services like Facebook, there are definite similarities. They offered users a forum for posting and replying to public messages, a kind of email and often games. In contrast to modern social networking services, BBSes were almost exclusively local, with users often meeting up in real life as well as through their computers. In 1978, Ward Christensen and Randy Suess created the first public BBS, taking advantage of a blizzard in their hometown of Chicago to build it. The idea quickly spread across the country and around the world. For an entertaining look at BBS culture through the eyes of the people who lived through its heyday, check out Jason Scott’s excellent "BBS: The Documentary." It's Creative Commons-licensed, so you can watch it guilt-free on YouTube.


Hayes Revolutionizes the Modem Market

Early modems were clunky affairs, with the acoustic coupler and the need to dial the phone numbers yourself. The Hayes Smartmodem, introduced in 1981, changed the market forever. It had the ability to plug directly into the phone system (thanks to the previously mentioned legal decisions) and could dial numbers directly, as well as answer calls automatically. Despite its price, these features made the Smartmodem very attractive to BBS operators, known as "sysops." Unfortunately for Hayes, a lot of other manufacturers liked the Smartmodem’s features and duplicated them on devices that sold for a fraction of the cost. Soon, a number of "Hayes-compatible" modems popped up, eroding Hayes’ original market. Hayes managed to hang on until the 90s, when it filed for Chapter 11. The name is still in use.

Increasing Speeds and the Growth of the Internet

The speed of modems continued to get faster and faster. The first modems were 300 bits per second, then 1200 bps, then 9600 bps, 14.4k, 28.8k and 56k. Advances in echo cancellation and noise-reduction technology helped make these possible. At the start of the 90s, the Internet was making its way from universities and research labs into public consciousness, which also provided demand for more, better and faster modems. Instead of an add-on, they became standard equipment on new PCs. But the fastest dial-up modems were still not fast enough. With the explosion of the World Wide Web, users wanted to surf even faster. They turned to services like cable and DSL, which provided faster broadband access. However, DSL and cable modems weren’t strictly modems in the traditional sense, as they had a completely digital signal path. The popularity of mobile computing lead to the growth of wireless technology, including Wi-Fi. Of the modern devices, Wi-Fi might be the closest to the traditional modem, as it encodes data into radio waves and turns radio waves back into data.

Most people in North America use broadband these days, while only three percent still use dial-up. The way we access the Internet has also changed, as more people log on with smartphones or other mobile devices, often bypassing the traditional PC. Even with all of the changes we’ve seen, it’s always important to remember that we didn’t just wake up one day and have the Internet. Looking back to see where we've been is a way to appreciate how far we've come…and perhaps how far we still have to go.


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David Delony
David Delony

David Delony is a Bay Area expatriate living in Ashland, Oregon, where he combines his love of words and technology in his career as a freelance writer. He's covered everything from TV commercials to video games. David holds a B.A. in communication from California Sate University, East Bay.