facts about the invention
of the PC Modem by Dennis
and Dale Heatherington in 1977.
device that converts between analog and digital signals. Digital signals, which are used
by computers, are made up of separate units, usually represented by a series of 1's and
0's. Analog signals vary continuously; an example of an analog signal is a sound wave.
Modems are often used to enable computers to communicate with each other across telephone
lines. A modem converts the digital signals of the sending computer to analog signals that
can be transmitted through telephone lines. When the signal reaches its destination,
another modem reconstructs the original digital signal, which is processed by the
receiving computer. If both modems can transmit data to each other simultaneously, the
modems are operating in full duplex mode; if only one modem can transmit at a time, the
modems are operating in half duplex mode.
To convert a digital signal to an analog one, the modem generates a carrier
wave and modulates it according to the digital signal. The kind of modulation used depends
on the application and the speed of operation for which the modem is designed. For
example, many high-speed modems use a combination of amplitude modulation, where the
amplitude of the carrier wave is changed to encode the digital information, and phase
modulation, where the phase of the carrier wave is changed to encode the digital
information. The process of receiving the analog signal and converting it back to a
digital signal is called demodulation. The word "modem" is a contraction of its
two basic functions: modulation and demodulation.
|Dennis C. Hayes and Dale
Heatherington invented the PC modem in 1977,
establishing the critical technology that allowed today's online and Internet industries
to emerge and grow.
They sold the first
Hayes modem products to computer hobbyists in April of 1977 and founded D.C. Hayes
Associates, Inc., the company known today as Hayes Corp., in January of 1978. Hayes
quality and innovation resulted in performance enhancements and cost reductions that led
the industry in the conversion from leased line modems to intelligent dial modems - the PC
- Hayes-Compatible, in computer science, an
adjective used to describe a modem that responds to the same set of commands as a modem
manufactured by Hayes Microcomputer Products, originators of the de facto standard for
Computing from The Great Idea
ON THE WEB:
Zoom Telephonics, Inc.
This company acquired most of the modem assets of Hayes Corporation.
and Fall of the Modem King
Dennis C. Hayes begins selling personal computer modem products to
computer hobbyists. Initially, the modems are boards for the S-100 bus,
and later for the Apple II. International Herald Tribune. Article by
CRN Industry Hall Of Fame
USIIA chairman, Hayes advocates effective Internet policy, a role born
from his invention of the PC modem in the late 1970s. CMP article by
There was a time when Hayes compatible meant something.
The organization that now sets modem standards is the International
Timeline of computer history from BC to the present. Presented by
Computer Hope, free help for computer users.History for 1960 - 1980
HOW IT WORKS:
How Modems Work
From the popular How Stuff Works Web site by Marshall Brain. Lots of COOKIES
and POP-UP ADS at this site.
DID YOU KNOW?
- 1978 -- Dennis C. Hayes and partner
Dale Heatherington, working on Hayes’ dining room table, develop
first personal-computer modem and formed a company.
- 1985 -- Hayes annual sales hit $120
million as popularity of home computers grows.
- 1988 -- Hayes and first wife Melita
divorce after six years of marriage.
- 1994 -- Hayes Microcomputer files
for Chapter 11 bankruptcy reorganization.
- 1996 -- Company emerges from Chapter
- 1997 -- Company merges with Access
Beyond of Gaithersburg, Md.
- 1998 -- Hayes Corp. files for
- 1999 -- January 6, Hayes shuts down
- 1999 -- April. 7, Zoom Telephonics
Acquires Hayes Modem Assets Source: Hayes Corp
Sources in BOLD Type
page revised January 24, 2006.
Berners-Lee's invention has revolutionized the world like nothing
The invention of the Internet,
should be classed with the greatest events of the 20th Century.
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