Telephone lines were designed to carry the human
voice, not electronic data from a computer. Modems were
invented to convert digital computer signals into a form
that allows them to travel over the phone lines. Those
are the scratchy sounds you hear from a modem's speaker.
A modem on the other end of the line can understand it
and convert the sounds back into digital information
that the computer can understand. By the way, the word modem
stands for MOdulator/DEModulator.
Buying and using a modem used to be relatively easy.
Not too long ago, almost all modems transferred data at
a rate of 2400 Bps (bits per second). Today, modems not
only run faster, they are also loaded with features like
error control and data compression. So, in addition to
converting and interpreting signals, modems also act
like traffic cops, monitoring and regulating the flow of
information. That way, one computer doesn't send
information until the receiving computer is ready for
it. Each of these features, modulation, error control,
and data compression, requires a separate kind of
protocol and that's what some of those terms you see
like V.32, V.32bis, V.42bis and MNP5
If your computer didn't come with an internal modem,
consider buying an external one, because it is much
easier to install and operate. For example, when your
modem gets stuck (not an unusual occurrence), you need
to turn it off and on to get it working properly. With
an internal modem, that means restarting your
computer--a waste of time. With an external modem it's
as easy as flipping a switch.
Here's a tip for you: in most areas, if you have Call
Waiting, you can disable it by inserting *70 in front of
the number you dial to connect to the Internet (or any
online service). This will prevent an incoming call from
accidentally kicking you off the line.
This table illustrates the relative difference in data
transmission speeds for different types of files. A
modem's speed is measured in bits per second (bps).
A 14.4 modem sends data at 14,400 bits per second. A
28.8 modem is twice as fast, sending and receiving data
at a rate of 28,800 bits per second.
Until nearly the end of 1995, the conventional wisdom
was that 28.8 Kbps was about the fastest speed you could
squeeze out of a regular copper telephone line. Today,
you can buy 33.6 Kbps modems, and modems that are
capable of 56 Kbps.
Speed It Up
There are faster ways to transmit data by using an ISDN
or a Leased Line. ISDN requires a so-called ISDN
adapter instead of a modem, and a phone line with a
special connection that allows it to send and receive
digital signals. You have to arrange with your phone
company to have this equipment installed.
An ISDN line has a data transfer rate of between
57,600 bits per second and 128,000 bits per second,
which is at least double the rate of a 28.8 Kbps modem.
Leased lines come in two configurations: T1 and T3. A T1
line offers a data transfer rate of 1.54 million bits
per second. Unlike ISDN, a T-1 line is a dedicated
connection, meaning that it is permanently connected to
the Internet. This is useful for web servers or other
computers than need to be connected to the Internet all
the time. It is possible to lease only a portion of a
T-1 line using one of two systems: fractional T-1
or Frame Relay. You can lease them in blocks
ranging from 128 Kbps to 1.5 Mbps. A fractional T-1 will
be more expensive at the slower available speeds and
Frame Relay will be slightly more expensive as you
approach the full T-1 speed of 1.5 Mbps. A T-3 line is
significantly faster, at 45 million bits per second. The
backbone of the Internet consists of T-3 lines.
Leased lines are very expensive and are generally
only used by companies whose business is built around
the Internet or need to transfer massive amounts of
data. ISDN, on the other hand, is available at a price
many families can afford.
Wireless DSL is another high-speed technology that Dluxlink
is offering in limited areas. Wireless DSL is always
connected to the Internet, so you don't need to dial-up.
Typically, data can be transferred at rates up to 1 Mbps
downstream and upstream.. Since Wireless DSL is wireless
you don't have to install another phone line. Visit our Wireless
DSL FAQ for more information