ADSL2+ broadband delivers Internet services over your phone line. Here’s what you need to know to pick the right plan.
How does ADSL work?
ADSL (Asymmetric Digital Subscriber Line) internet services work by sending data signals along the existing copper infrastructure that has been used for telephony services for decades now. Those copper lines have more bandwidth than is needed just for telephone calls, and it’s those additional frequencies that are used for both ADSL and ADSL2+ connections.
The "A" in ADSL/2+ stands for Asymmetrical, because the ratio between download speeds and upload speeds on ADSL connections is always tilted towards downloads. That does largely follow the patterns of most Internet users, because you tend to consume more than you create. Read more>>
ADSL/ADSL2+ has some significant limitations, including the quality of the copper lines between your home and the exchange that handles your Internet traffic; this is quite variable however depending on the life of the copper and its maintenance cycle. A more fixed and pressing problem for ADSL/2+ connections is the question of distance from that exchange. It can vary depending on line quality, but as a rough rule of thumb, ADSL services won’t work at all beyond around 5km from an exchange, and the further out you go within the limit, the lower the available connection speeds will drop. That distance can be tricky to calculate exactly from the consumer end, because it’s not a straight line, but instead also hinges on the lengths and quality of copper between your home and the exchange.
ADSL broadband relies on having a connection point at a telephone exchange within that 5km distance from the exchange as well. In some cases you may find that ADSL provisioning cannot take place due to a lack of connection points at a given exchange.
Because ADSL uses different parts of the available copper bandwidth, you do not have to run a regular landline service and pay line rental fees for that service if you don’t use a landline phone regularly. These kinds of services disable access to voice frequencies to deliver a product most frequently referred to as "Naked" DSL.
How fast is ADSL?
ADSL connections in Australia are divided between connections that use the older ADSL standard, although these are becoming increasingly rare, and the faster ADSL2+ standard.
For the distance and quality related reasons above, ADSL/2+ speeds are always marketed as being "up to" approximations, because the distance between you and the exchange and then the ongoing issues of network congestion and end points on the Internet can radically affect your speeds. In typical terms, ADSL maxes out at around 8Mbps download and 384Kbps upload, while ADSL2+ connections can deliver download speeds of up to 24Mbps and upload speeds of up to 3Mbps. As noted, in effective real world use you’re unlikely to see anywhere near those speeds unless you’re very close to your exchange point.
Finally, it’s worth noting that if you access your ADSL/ADSL2+ connection via Wi-Fi, you’re likely to suffer a small speed penalty relative to the same connection used via a fixed Ethernet cable.
Where is ADSL available?
ADSL services are available across Australia wherever you’re within radius of an exchange; most ISPs will request your address as a primary step to ascertain ADSL availability in your region. Most notably if you are in an area where fixed line (FTTP, FTTN or FTTB) NBN is installed you will find the copper decommissioned over time, meaning that ADSL services will no longer be available.
How can I compare ADSL plans?
The speed of an ADSL/ADSL2+ plan is somewhat outside the control of your ISP or your own hardware due to the distance and line quality limitations of ADSL itself, as described above. One area however where you can compare speeds is for plans with a quota that drop down to "shaping" once your quota is exhausted. The precise speed offered as a top is usually a fraction of your normal ADSL speed, and that you can compare between ISPs
ADSL plans are the most widespread in use in Australia while much of the country awaits the rollout of the NBN. As such, price competition is strong, with many ADSL providers offering bundles that include line rental or unlimited data provisions.
Will I need a new modem for ADSL?
With DSL connections, whether they’re ADSL or ADSL2+ making up the majority of fixed line broadband connections in Australia, the odds are pretty good that your existing modem will work with ADSL services. That being said, if you jump up from ADSL to ADSL2+, you’ll need an ADSL2+ compliant modem or modem router to take advantage of the additional speed on offer. That’s only likely to be an issue if you’ve owned your existing modem for a very long period of time; any new ADSL modem router sold in Australia now will be fully ADSL2+ compliant.
If you’re transitioning from a fixed line HFC cable service to ADSL you will however need a new modem to connect to ADSL services, as the modems supplied by Optus and Telstra for their HFC products are not ADSL compliant. Check with your ISP if they bundle a modem in with a service, as many do if you want to save a little money, although be aware that the modems and routers provided by ISPs are generally simple units, so if you want the fastest Wi-Fi performance you may find it a little lacking if you go down the bundled freebie route.
What other extras should I look for?
The range of bundling with DSL services can be quite wide, especially if you’re prepared to sign up for a two year contract. On the hardware side over time this has encompassed everything from games consoles to included smartphones, but deals vary widely.
The other extra if you’re looking at a plan with a strict data quota is whether or not your ISP has quota-free provisions for certain sites or types of content. Again this varies by ISP and affiliation, but as an example Telstra makes most of its own services (streaming NRL/AFL, BigPond Movies) quota free for its customers, while iiNet and Optus offer Netflix content quota-free. Some ISPs offer access to specific gaming servers as part of a package, while others will include additional online services such as web space or additional email inboxes with some plans.