Introduction; How A Modem Works - US Robotics 33600 User Manual

Introduction

How a Modem Works

A modem is a computer peripheral that allows you to
communicate with other computers via telephone lines. Because
ordinary telephone lines cannot carry digital information, a
modem changes the digital data from your computer into analog
signals, which can be transmitted much like voice signals. In a
similar manner, the modem receiving the call then changes the
analog signals back into digital data that the receiving computer
can understand. This shift of digital data into analog signals and
back again allows two computers to "speak" with one another.
Called modulation/demodulation , this transformation of data and
signals is how the modem received its name.
Sportster Winmodem 33600 & x2/56K - User's manual 1