ADSL(Asynchronous
Digital Subscriber Line)
Jump to Information Links (below)
Summary
ADSL is a service that can use normal telephone lines for digital
communications concurrently with normal telephone use. It does this
by using a bandwidth spectrum outside the bounds used by normal voice,
fax and traditional modem communications.
ADSL connections can reach as high as 8Mb/s (or 8,000Kb/s) which is
significantly faster than a traditional modem at 56Kb/s. In reality,
providers allow ADSL at fixed and conservative levels. Currently in
Australias, ADSL is available at speeds of 64Kb/s, 128Kb/s, 256Kb/s,
512Kb/s and 1.5Mb/s.
Because ADSL is asynchronous, it means the provider can configure
it to have different speeds for data travelling in different directions.
Typically, ADSL is supplied at a higher speed download compared to
their upload. This is appropriate and useful for most Internet connections.
The fact that it uses a bandwidth spectrum outside normal telehone
use means that you don't need an extra line installed just for Internet
Access - you can use any existing lines that do not interfere with
the spectrum that ADSL uses. Some services that may interfere is certain
brands of PABX (internal telephone system), Monitored alarm systems
and services such as call-waiting. For business use, this can normally
be easily avoided by using your business fax line to also run ADSL
because fax lines are often dedicated to faxing only.
ADSL is an exchange-based technology. This means that activation,
configuration and function occurs at the telephone exchange. This
is why it is implemented by a telecommunications company and often
made available for re-sale by ISP's
This leads to another potential problem with ADSL is that you do not
have guaranteed bandwidth because the bandwidth to/from the exchange
(which may have many ADSL connections) is shared among all connections.
This is not much different from congestion issues that normal ISP's
face with modem dial-in's, but is technically avoided by using alternative
technologies such as ISDN. In our experience, this problem is relatively
rare.
It is the economics of ADSL that make it so useful. It is significantly
cheaper than all other forms of broadband Internet access (ie. faster
than 56Kb/s) and even compared to a high-availability modem connection
it is only marginally more expensive for up to 5 times the speed and
permanent connectivity.
Typical Monthly Modem Dialup Costs - 56Kb/s
ISP Subscription: $40
Telephone Line Rental: $25
Telephone Calls: $10
$75 per month
Typical Monthly ADSL Costs - 256/64Kb/s
ISP Subscription: $85
$85 per month
ParadigmIT can direct you to a number of local ADSL providers if you
wish to explore these options as well as provide valuable additional
services for making the most out of your broadband connection
More information on ADSL can be found at the
following places:
Definition and WhatIs.com
Whitepaper
on ADSL implementation
Search
Results from Hotbot.com
Some West Australian providers are Telstra,
IiNet
and RequestDSL
 |
|
|
