Modem: a device that converts between analog and digital signals.

When I first became interested in how the computer works, modems were very fascinating.
I had gathered tidbits of info on how the signals are changed from Analog to Digital and then back again. The following is basically what I understood the process to be:

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 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 Modem.

 

I always had a Hayes Compatible Modem. They may have been a little cheaper. This probably explains why the Hayes company went out of business in 1999:

 

TIMELINE:

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 11.

1997 -- Company merges with Access Beyond of Gaithersburg, Md.

1998 -- Hayes Corp. files for Chapter 11.

1999 -- January 6, Hayes shuts down Its operations.

 

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 microcomputer modems.

The 56K modem was invented by Dr. Brent Townshend in 1996.

I remember when the 56k modem came out. I was using a 28,800 dial up, upgraded from a 14,400. I thought the upgrade would take me to the speed of sound, but the 56,600 had disadvantages to the new 56k. I opted for the K (for Karen).