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Getting connected: a history of modems

Then, in 1977, Dale Heatherington and Dennis Hayes created the world's first PC modem, the 80-103A.

A modem that offered all the right features at exactly the right price point and connected directly to the phone, something that users had not had the luxury of experiencing until this point.

Dale heatherington

FIRST PC MODEM: Dale Heatherington with IMSAI 8080 computer and early 300 baud Hayes modem [Image credit: Dale Heatherington]

Usually you'd have to dial the phone manually or use a dialer plugged into the computer.

It was so successful that they started up DC Hayes Associates, later known as Hayes Microcomputer Products, and developed several landmark technologies including the Smartmodem and the Hayes Command set.

Dennis hayes

PIONEER: Dennis Hayes in 1976 [Image credit: Dale Heatherington]

The Smartmodem was remarkable because it could switch between data mode and command mode and it did this using a sequence known as the Hayes Command Set that incorporated a unique "guard time" to prevent the data being sent from confusing the modem itself.

The Hayes Command Set has remained one of the most popular although it has been substantially built upon since its inception to accommodate higher speeds and better technologies.

Faster rates

Soon after 2400 baud modems hit the market on V.22 BIS, they doubled transfer rates and came with new data compression standards and introduced V.42 the Auto Reliable Protocol.

Speed was noticeably faster and transmissions were substantially more error free along with better compression.

The short-lived 4800 baud modem followed in the 1990s beaten down by the 9600 baud modem that became available in 1991.

The latter used single sideband transmission so modems could use two channels on the phone line instead of one.

It was the development of echo cancellation that allowed for this breakthrough in speeds as modems were now able to determine whether the signals they were receiving were from themselves or from other modems and "cancel" their own signals to prevent confusion.

It took 14 years, from 1980 until 1994, for the speed of the modem to develop from 14.4Kpbs to 28.9Kbps but it was only two years later, in 1996, that Brent Townshend came up with the technology for the 56k modem.

US robotics 56k modem

SUPER-SPEED: The 56k modem created by US Robotics [Image credit: Xiaowei]

"We started with a very specific problem - how do we get higher speed data from the digital server to many analog links - and started working on it from that point of view," Towshend explained to Network World in 1997.

Townshend didn't go into the business of making modems; instead he merely took out the patented and licensed the technology for a substantial $2.50 per modem.

This has dropped to 22 US cents per soft modem today but it's not hard to imagine that he's swimming happily in a pool of money round about now.

Of course most of us are now enjoying the blistering speeds offered by ADSL but the dial-up modem still remains in circulation and its history is one of the most interesting to read.

It's fascinating that development was not as rapid as many modern technologies and that, for many years, people were happy with the snail-like speed of 300 baud.

The modem heralded a new age of communication and initiated the widespread use of the internet; achievements that we now take for granted but could not be conceived of as recently as the 1980s.


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