What is ADSL?
Asymmetric digital subscriber line (ADSL) is a very popular form of high speed broadband and is offered by many Australian internet service providers (ISPs). The asymmetry in an ADSL service is the feature that allows you to download data more quickly than you are able to upload data, which meets the data needs for most internet users.
What are the advantages of ADSL?
ADSL uses the copper pair telephone line, which also carries voice traffic, to deliver high speed internet access to your premises.
ADSL is considered to be an ‘always on’ service which means you can be connected to the internet whenever your computer and ADSL modem router are powered on.
Unlike dial-up internet access, ADSL operates above the voice band so you can make a telephone call and browse the internet simultaneously with no interruption to either service. This process is known as spectrum sharing.
It means that:
- there is no need for an additional telephone line service and
- there is no need to make a dialled call to the ISP
It is possible also to have different service providers for the standard telephone line service and the ADSL internet service.
Can I get ADSL?
The availability of ADSL is dependent on a number of factors, including the nature of the copper pair connection to your premises, the quality of your existing telephone line and the distance to your nearest telephone exchange.
ADSL services require an 'unconditioned' telephone line. Unconditioned means the telephone line that provides your current telephone line service is continuous all the way back to your local exchange. In addition, the telephone line must not have any network conditioning devices or attachments that might modify its inherent electrical characteristics. If other network devices or components are attached, you may not be able to access ADSL services unless they can be and are removed from the line.
To acquire an ADSL service, your local exchange must be 'ADSL enabled'. This term is used to describe exchanges where ADSL equipment has been installed by an ISP. To confirm that your local exchange is ADSL enabled, contact your ISP.
What equipment do I need to connect via ADSL?
You may need some or all of the following:
- a standard telephone line service
- an ADSL modem router that connects you to your ISP
- installation software to install and configure the modem router
- a telephone cable (also known as RJ-11 cable)
- an in-line or micro filter for each installed telephony device (up to 3 devices) to avoid interference between your ADSL and fixed line telephone connection, or
- a central filter (master splitter) if you have more than three telephony devices installed. If you need a central filter it may need to be installed by a registered cabler. See the phone, data or alarm cabling fact sheet for further information.
Who installs and supplies ADSL?
If you are an experienced computer user and the installation does not require a registered cabler, you may find that you are able to install the required devices yourself. Alternatively, your ISP may be able to arrange the installation for you. Be sure to ask your service provider which installation options are available.
Enhanced versions of ADSL
Australian ISPs may offer different versions of ADSL broadband some of which may provide you with higher data rates. ADSL2 and ADSL2+ are two such enhanced versions of ADSL.
ADSL, ADSL2 and ADSL2+ services require you to have a fixed telephone line service as the ADSL service shares the copper pair to your local exchange with the telephone line service. Another variant of ADSL, known as Naked DSL, can provide you with a high speed internet service without the need of a standard telephone line service.
ADSL, ADSL2, ADSL2+ and Naked DSL are not available in all exchanges in Australia, so check with your ISP for service availability.
More information on internet technology is available on the ACMA’s website, at ;www.acma.gov.au (go to For the public > Consumer and community advice).
The ACMA has fact sheets on various topics.
Please note: this document is intended as a guide only and should not be relied on as legal advice or regarded as a substitute for legal advice in individual cases.