Digital Subscriber Line (DSL)
terms
Many customers are often confused
by some of the terms related to DSL. Here are a few
definitions to help you out:
DSL
Digital Subscriber Line is best
described as a telephone line on steroids. It uses
copper-based, ordinary telephone wire that is connected
to your service box in much the same manner as regular
telephone lines are. The difference: DSL technologies
use sophisticated modulation schemes to pack data onto
the copper wires -- this "ramps up" the speed. These
modulation schemes are used only for connections from a
telephone company's Central Office to a user's home or
office.
With this extra speed comes a
price: DSL is only available within an 18,000-foot
(3.4-mile) radius of the CO.
CO (Central Office)
A Central Office is the location
of the local telephone provider's switching equipment.
In the first half of the 20th Century, the CO was where
banks of switchboards were staffed by human operators.
There may be more than one CO in a
city; in fact, in Miller & Miller IMS, Inc.'s city,
there are two CO's -- one on the north side (downtown)
and one on the south side.
Loop
The wiring that exists between
your home or business and the CO. If your loop is long
than 18,000 feet, DSL is most likely not available for
you. If it contains fiber-optic cable, you may need IDSL.
SDSL (Synchronous Digital
Subscriber Line)
SDSL is a business-class,
high-speed Internet access meant to provide the best
upload and download speeds that will meet the unique
requirements of businesses.
With SDSL, the upload and download
speeds are the same, usually expressed in megabits per
second (Mbps) and kilobits per second (Kbps).
IDSL (ISDN Digital Subscriber
Line)
ISDN stands for Integrated
Services Digital Network. Because DSL is a copper-based
technology, if fiber-optic lines exist between the CO
and the location where the DSL customer will use it, the
service provided must be IDSL.
The presence of fiber in your loop
may require you to use IDSL. The maximum speed for IDSL
is 144 Kbps.
ADSL (Asynchronous Digital
Subscriber Line)
With SDSL, the upload and download
speeds are the same. The difference with ADSL is that
the upload speed is different -- slower -- than the
download speed.
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