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What
is DSL? by Frederic Martin, workingarts
Marketing
Background
information
The telephone infrastructure is mostly built with switches and copper
wire. The performance of your computer's modulator/demodulator (modem)
is limited by the physical wire to 33,000 bits per second (33 kbps). Today's
modems feature 56kbps technology which enhances the wire's speed limitation
by combining compression technologies that allow your connectivity to
reach speeds between 45 and 56 kbps.
How does
DSL work?
Digital Subscriber Line (DSL) provides high-speed Internet access
over the telephone lines that are already linking your home or office
to the existing telephone switches at the telephone company's Central
Office (CO). DSL uses a bridge or router, installed at your location,
that is connected to a Digital Subscriber Line Access Multiplexer (DSLAM)
located at the CO. The DSLAM is owned by the telephone company or by your
broadband Internet Service Provider (ISP), who leases space to collocate
the DSLAM at the CO. The copper phone lines that connect to the bridge/router
at your location travel through the DSLAM in the CO to enable high-speeds
on the line. The DSLAM is connected to your ISP, who, in turn is connected
to the Internet. DSL allows you to send and receive data at speeds up
to 1.1 Mbps (35 times faster than a 28.8 Kbps modem). Theoretically, DSL
can reach 32 Mbps (over 100 times 28.8 connections), however, the real
world brings it down to an average of 300 kbps, which is about 10 times
your typical modem connection's performance.
Why do
I need faster connectivity to the Internet?
If you receive an E-mail with a 2 MB attachment (a presentation, large
graphic, sound file, or a large text document), it would take you over
9 minutes to download with a 28.8 Kbps modem connection. With DSL, you
could open the attachment within 15 seconds. For example, downloading
Netscape Communicator 4.7 with a 28.8 Kbps modem would take you over an
hour, but doing the same thing with DSL it would take you approximately
2 minutes.
"Always
on" connectivity
With DSL, you no longer have to dial up, deal with busy signals, wait
until your computer is connected. The Internet instantly delivers your
requested content.
Fast
Connections.. yes, but at what price?
Until now, "always on", high-speed Internet connectivity has
been affordable only to large corporations, who pay thousands of dollars
for T1 and T3 lines -- T3 lines have the combined power of about 1300
28.8 modems!!
DSL provides high-speed access for a fraction of that cost. Now any business
or individual can afford a full-time connection to the Internet, allowing
you to increase your productivity at work or shop on the Internet from
home without those long and frustrating downloads you experience with
modem dial up connectivity.
Broadband
Policy|TechTeam|Madera
Chamber of Commerce
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