Chapter 15
Modems: The Essential
Translators
In This Chapter
Ringing the bell, Twenty-First Century style
Differentiating among dial-up, cable, and DSL designs
Going inside or hanging on the outside
M
odems are the entry ramp to the information superhighway. They are —
trust me on this — relatively simple devices that are absolutely essential
when it comes to translating between the digital 0s and 1s that exist within a
laptop and the analog electrical pulses that travel over telephone wires, cable
television coaxials, and fiber optics, and through the air in wireless radio or
infrared communication.Okay, let me break this down: I have previously examined the digital nature
of the computer, where everything is stored, transported, and manipulated in
the form of binary math. Numbers are created out of 0s and 1s and are used
to represent letters, characters, the elements of a graphical image, and the
representation for music and other audio.A computer’s special-purpose circuits are perfectly capable of moving huge
blocks of data over relatively short distances using 8-, 16-, and even 32-wire-wide
parallel paths. But when the computer needs to send and receive data over a
greater distance, the pathways are not conducive to parallel transmissions
and not set up to transmit discrete digital 0s and 1s.It All Started with Mr. Bell ...........................................................................
Why, you might ask, don’t computers merely send 0s and 1s in digital form
across the phone lines in the same way a PC does when it sends information
to a printer? The answer goes back to the original purpose of the telephone
system: to send a version of the human voice from one place to another.