The Evolution Of Dialup Modems

A modem is typically a device used to transmit data over a phone line ina dialup internet connection. The word "modem" is a retrenchment of the words modulator-demodulator. Its main function is to transmit data to both the sides (computer and phone line) in the form compatible to the concerned side. The sending modem modulates the data into analog signal that is compatible with the phone line, and the receiving modem demodulates the signal back into digital data compatible to computer.

Modems came into existence in the 1960s. The early modems were exclusively used to allow dumb terminals to connect to computers over the phone lines. That was the age of time-shared computers. Hence, a business could buy computer time from a time-share facility and connect to it via modem. These early modem could transmit data at a speed of 300 bits per second. In systems existed at that time, a dumb terminal consisted simply a keyboard and a monitor. The most commonly used dumb terminals could display 25 lines at a time and 80 characters in each line on the monitor screen. When the user typed a character on keyboard of the dumb terminal, the modem sent the ASCII code for the character to the central computer. The central computer then sent the character back to the computer so it would appear on the screen. This mode of data transfer was extensively used to enable dumb terminal at a remote site to dial in to a large, central computer.

The use of the modems was further extended to home uses in 1970’s when personal computers started appearing. With the modem technology available at that time, bulletin board systems (BBS) became highly popular. A user could set up a computer with a modem and BBS software and other people would dial in to connect to the bulletin board. The users would run terminal emulators on their computers to emulate a dumb terminal. The bulletin boards became a popular source of sharing information. The era of the 300 bps modems went on in this time of character-based computers. The reason is that the speed was sufficient to run the character based data transfers as the modem could transfer about 30 characters per second. This is a lot more characters per second than a person can type or read.

The evolution of the modems went further with the introduction of Internet and dial up Internet access in 1980’s. The 300 bps modems went out of use once the once GUI (graphical user interface) was introduced. With advancement of internet, people started transferring larger programs and images over the Internet though next generation modems that were capable of transferring data at 900 to 1200 bps. As the data transfer over the Internet increased rapidly in 1990’s, modems also improved on their speeds. Modems that could transfer data from 9600 bps to 33.6 Kbps came into use and gone. The most used modem in the mid 1990’s was the 33.6 Kbps modems. The final step in the evolution came in 1998, when 56Kbps modems become standard. The 56kbps modems are now most widely used modems in the world.