What is ADSL?

ADSL stands for 'Asymmetric Digital Subscriber Line'. It provides high speed, always-on access to the Internet from your home or business telephone line,.

By sending digital signals over the telephone line, it provides broadband Internet access without interrupting your normal (and concurrent) use of the telephone line for placing and receiving phone calls.

It provides an effective way to provide Internet access in a variety of situations, without the complications of configuring and operating a modem. It has a number of technical advantages compared to accessing the Internet via a dialup modem or other means.

How fast is DSL?

You have a choice of access speeds with ADSL:

256k/64k, which means that your peak download speed is 256 kilobits per second, and your peak upload speed (back to the Internet) is 64 kilobits per second,

512k/128k, which means that your peak download speed is 512 kilobits per second, and your peak upload speed (back to the Internet) is 128 kilobits per second,

1500k/256k , which means that your peak download speed is 1500 kilobits per second (or 1.5 Megabits per second), and your peak upload speed is 256 kilobits per second.

Compare these speeds to a conventional modem, which typically can download at around 45 kilobits per second and upload at around 31 kilobits per second, and you can see the dramatic speed difference available with ADSL - up to 30 times faster than a modem, with no dropouts, and no blocking of your normal telephone service.

What advantages does ADSL offer?

• It is always-on - the connection is always available without needing to wait for ages to 'dial up'. It also doesn't 'drop out'. It is 'just there' - when you need it, instantly.
• It is dramatically faster than a dial modem or ISDN connection - up to 30-50 times faster, in fact! This makes an enormous difference to the effectiveness of your Internet experience
• ADSL seamlessly 'shares' a phone line along with normal 'voice' services. Your phone is not engaged when you are using the Internet - in fact you can freely use the phone at the same time as you access the Internet! No more busy signals for people trying to contact you while you surf.
• No second phone line needed. You can easily offset the costs of ADSL by $30 per month or more - this is the amount you might have otherwise spent on a second phone line and on local calls to access the Internet with a modem, without interrupting the use of your primary telephone service.
• You can save time and frustration by never having to wait for a modem to connect, or suffering connection dropouts, in addition to the hugely increased download speeds available
• It is far more cost effective than any previous alternatives for providing broadband connections to most home or office locations. Most other technologies providing access at more than 256 kilobits per second to residential and small business environments are more expensive than ADSL

What are the limitations of ADSL?

Nothing is perfect, and ADSL is no exception.

There are a few technical limitations and issues to be aware of when contemplating an ADSL connection to the Internet:

ADSL is not available on all phone services

           You may not be able to get ADSL for many reasons but the most common are:

• You are too far from the local telephone exchange.
• The local telephone exchange is not enabled.

ADSL is not a guaranteed bandwidth service

• Telstra's copper line network architecture, and the manner in which ADSL data is moved around the city, mean that network congestion is possible in your line at some times. The speeds quoted for ADSL services are theoretical maximum rates.
• Performance of the network may vary by time of day or may decrease over time due to increased network interference in the Telstra copper line network.

ADSL is only fast in one direction

• The asymmetric transfer rates provided by ADSL are designed to optimise the speed of Internet downloads.
• As a consequence, the upload speed on ADSL is far slower.
• This means that ADSL is often unsuitable for situations where you intend to upload (or serve) large quantities of data from your location back out into the Internet.