" ...Getting Connected (1 of 4) -- The modem"

     A modem is a sort of translator between computers and the phone
system. It's needed because computers and the phone system process and
transmit data, or information, in two different, and incompatible ways.
Computers "talk" digitally; that is, they store and process information
as a series of discrete numbers.  The phone network relies on analog
signals, which on an oscilloscope would look like a series of waves.
When your computer is ready to transmit data to another computer over a
phone line, your modem converts the computer numbers into these waves
(which sound like a lot of screeching) -- it "modulates" them.  In turn,
when information waves come into your modem, it converts them into
numbers your computer can process, by "demodulating" them.
     Increasingly, computers come with modems already installed. If yours
didn't, you'll have to decide what speed modem to get.  Modem speeds are
judged in "baud rate" or bits per second.  One baud means the modem can
transfer roughly one bit per second; the greater the baud rate, the more
quickly a modem can send and receive information. A letter or character
is made up of eight bits.
     You can now buy a 2400-baud modem for well under $70 -- and most now
come with the ability to handle fax messages as well.  For $200 and up,
you can buy a modem that can transfer data at 9600 baud (and often even
faster, when using special compression techniques).  If you think you
might be using the Net to transfer large numbers of files, a faster modem
is always worth the price. It will dramatically reduce the amount of time
your modem or computer is tied up transferring files and, if you are
paying for Net access by the hour, save you quite a bit in  online 
charges.