DSL stands for Digital Subscriber Line,
a broadband technology that uses telephone lines and digital coding to create a connection to the Internet from
That link can carry vast amounts of voice, video and data information at very high speeds.
How does DSL work?
DSL service providers use the same copper-based
lines that let you make and receive telephone calls. To send data at high speeds carriers use the lines at higher
frequencies that telephone service doesn't need. DSL modems are connected at both ends of the line.
The modems digitally divide your telephone line into three channels: one for telephone traffic, one for upstream
data from your computer to the Internet and the third for downstream data traffic from the Internet to your computer.
I understand that there are several forms of
DSL service. What are they?
ADSL, HDSL, IDSL, SDSL, Universal DSL and VDSL.
ADSL (Asymmetrical Digital Subscriber Line) is designed primarily for the residential consumer market.
The asymmetricmeans that the connection transmits data at faster speeds downstream from the Internet to your computer
than upstream from your computer to the Internet. This is because DSL users rarely upload the same amounts of data
as they download.
ADSL can support speeds up to 8 megabits per second (mbps) downstream and up to 1 mbps upstream, although the connection
rarely approaches those marks.
HDSL (High-Speed Digital Subscriber Line) offers equally fast upstream and downstream data-transmission speeds
ranging from 784 kbps to 2 mbps.
IDSL (ISDN Digital Subscriber Line) also offers equally fast downstream and upstream speeds, but it's pegged at
SDSL (Symmetrical Digital Subscriber Line) offers similar upstream and downstream speeds ranging from 385 kbps
to 2 mbps.
Universal ADSL, which also is called "G.lite" service, is an easy-to-install DSL service primarily marketed
for residential use.
It supports downstream speeds of up to 1.5 mbps and upstream speeds of up to 512 kbps.
VDSL (Very High Bit-Rate Digital Subscriber Line) offers downstream speeds as high as 53 mbps and average upstream
speeds of 2 mbps.
I sometimes see the term xDSL. What's that?
It's a generic term for all forms
of DSL service spanning transmission speeds from 128 kbps to 52 mbps.
How fast is a DSL connection?
The technology can deliver data ranging from 128
kbps to 7.1 mbps.
That IS six to 125 times faster than the standard dial-up connection speed of 28.8 or 56 kbps.
A DSL broadband connection enables you to download huge files from the Internet in a fraction of the time it takes
a dial-up service, move from web site to web site as if you
were changing the channels on a TV set, access a growing range of news, entertainment and information resources,
including specialized services being developed expressly to take advantage of broadband's blazing speeds. You can
do more in less time.
What does "always on" mean?
Once you've turned on your computer and
clicked on your DSL connection to the Internet, you remain connected as long as your computer remains on.
There is no longer the need to dial a telephone number and then wait for your modem to connect you to the Internet
every time you go online.
An always-on connection lets you hop on and off the world wide web whenever you want with no delay.
You can send an e-mail at a moments notice or access vast databases at the flip of a switch.
What is DSL's biggest drawback?
A disadvantage of DSL is:
The speed that your DSL service provider boasts of for your connection can vary within a range and the access speeds
that are quoted at maximum rates. The same thing happens
with modems and dial up accounts. Variations in speeds are tied to the physical condition of the copper telephone
line used for your DSL connection or the number of computers hooked
up to your DSL link in your home or office.
Who offers DSL service?
Almost every telephone carrier in North
America and Europe is at some stage of DSL deployment. That ranges from Bells such as Qwest and SBC Communications
to independent companies such as GTE.
How much will a DSL connection cost me per
Again, it varies. Your monthly bill will
depend on your connection's speed and whether you've ordered extras like additional e-mail boxes.
A typical home user can expect to pay $27 to $50 a month for service.
Businesses can expect to pay from $100 to $200 a month.
What kind of equipment do I need?
First, a DSL modem, commonly called a "router"
It is usually leased from your service provider and included in your monthly bill. Also, your computer also must
connect to the router, which is done through an Ethernet cable that your DSL service vendor usually provides.
Finally, to transform a telephone line into a high-speed data line, DSL equipment must be installed on both ends
of the line. (at the customer premises and the local telephone central office).
Will a router run on my computer?
Most DSL companies require at least a Pentium
processor and 40 megabytes of free space on your hard drive.
If you purchased your computer within the last five years, you will probably meet those requirements.
How many DSL lines do I need?
You need one DSL connection for
every Internet connection you want.
With home networking more than one computer can share an Internet connection.
Can I use more than one computer on my DSL
Yes, but you will need unique High Speed
Internet User IDs and passwords for each computer if they're used at the same time. Also, be aware that using more
than one computer at a time can slow download speeds.