ADSL (Asymmetric Digital Subscriber Line) is a technology that allows high speed broadband internet access using a standard conventional copper telephone line.
If you're wondering how, ADSL uses a simple microfilter to separate the lower frequencies of your telephone line for voice telephony and much higher frequencies for data. Additionally (and hence the "asymmetric" bit), it allows more data to download than upload.
What does this mean to you? In practical terms, this means that you get to browse the internet and make phone calls at the same time with only one line. No more arguing over who gets to use the line. The other major improvement it offers is the fact that and ADSL connection is always on. Unlike dialup, you won't have to dial up slowly and noisily, and you'll receive e-mail and other messages as soon as they're sent to you.
If you are currently using a traditional dialup connection and want to improve the speed of your downloads, ADSL is usually the most reasonable option. ADSL speeds range from 256kbps (about 4 times faster than dial-up) to 8000kbps. At 1500kbps or faster connection is generally recommended for users looking to download music or watch videos online.
ADSL2+ is the term used to describe the fastest broadband speeds currently available in Australia. An ADSL2+ connection can reach speeds up to 24,000kbps but actual experienced speeds will depend on the location of the connection and the compatibility of the infrastructure on your service line.
A 2006 Internode sample survey revealed that 63% of subscribers to Internode ADSL2+ broadband plans experienced speeds in excess of 10,000kbps. 13.4% of subscribers achieved download speeds higher than 20,000kbps, while only 13.8% achieved speeds less than 5,000 kbps.
All ADSL2+ broadband plans require an ADSL2+ compatible modem that you can either purchase from you internet service provider or bring to the broadband plan. Some providers will offer a discounted modem when signing up to a contract.
The availability of an ADSL2+ connection depends on the installation of a DSLAM (Digital Subscriber Line Access Multiplexer) by an internet service provider at the local exchange. This basically means that an internet service provider needs to enable your area before you will be eligible for an ADSL2+ connection. The progress of your internet service provider in installing DSLAM’s at your local exchange depends on a number of factors including costs and a demand for ADSL2+ in your area. Serviceable areas vary from provider to provider with the larger Australian providers offering widespread coverage. For example, TPG has already enabled 170 exchanges, providing ADSL2+ access to millions of Australians.
Because internet service providers install their own infrastructure when supplying an ADSL2+ connection, they don’t have to pay rental to the major telecommunications providers. This means ADSL2+ connections are generally cheaper than an ADSL plan. With most providers, if ADSL2+ is available you will no longer be offered an ADSL connection. On the other hand, if there is "pair gain" or RIM on the line, you will have to settle for ADSL.
