Several of Australia's largest internet service providers are using the new naked DSL style of broadband to extend the reach of their services and eliminate customer black spots.
ADSL, by far Australia's most popular form of broadband, has historically been sold with a bundled analog telephone service. However, Internode product manager Jim Kellett said this bundling limited the distance from telephone exchanges at which customers could access broadband, to around four kilometres.
But with the advent of so-called naked DSL, where ADSL is sold without an attached voice line, ISPs like Internode and iiNet are starting to push the limits out to up to seven kilometres away from exchanges.
Internode has so far only been offering naked DSL using Optus' network, which maintains an inactive voice line connection, but will in the next couple of months commence using its own exchange hardware in some areas, which can facilitate naked DSL without any voice service at all.
"There's a lot of people who will be getting broadband who couldn't before," Kellett told ZDNet.com.au.
The company started a trial in November with 120 people in South Australia where it ran services for distances up to seven and a half kilometres from the exchange. "The trial exposed various wrinkles in the activation and separation processes," Kellett said.
One such problem was that the normal way to test a line fault was to check for a dial tone on the line. However, the Internode DSLAMs (network hardware in exchanges) didn't have a dial tone at all, precluding this fairly simple test. Instead, the checking was carried out from the DSLAM itself to see if a line was dead.
Currently the company is getting its internal services in order, and ordering the unbundled local loop service from Telstra which allows naked DSL, Kellett said, adding that it had not yet been decided if all the exchanges across the country would be turned on at the same time: "We may restrict it to Adelaide and Melbourne in the first two months. The sheer volume of calls will be hard to handle."
Kellett believes customer take-up will be good. The company has carried out a study to find out the number of people living four kilometres from an exchange, getting an almost six-figure answer. "We were quite staggered by the potential number of customers," Kellett said.
iiNet chief technology officer Greg Bader said his company was already offering naked DSL on its own equipment, allowing the same distances to be achieved as Internode. "We've had some customers working at six to seven kilometres. Some of them get a fantastic service," he said.
However, these people are not a focus of iiNet's, he said, adding that although there are some who can't be served under the line sharing service (a predecessor to ULL), they could instead be served by unbundled local loop, but he didn't think the numbers were large.
There are other causes for black spots than distance, he said. "It's not going to solve every one." There have been cases, he continued, where up to 5Mbps has been achieved at seven kilometres on one line, but only 512Kbps at 500 metres on another line.
This isn't anything new. ADSL was always designed to work 7KM and more from the exchange - however the further you go though by cable length, the further the speeds decrease as the frequency roll off of the cable causes the bandwidth to be limited. It's much the same as "one" of the theories behind a 56K modem only training at a slower speed... (I'm not going to mention pair gain equipment)
It's only because customers expect that paying for a up to 24MBit/s service get a 24MBit/s service, when it's not possible in all cases that caused the problem in the first place. Telstra would have had to limit the KM from the exchange in order to "Guarantee" certain speeds for dumb arse customers who can't accept that 3KM is a long distance and has technical limitations. (Sure, there are other technical problems also like joints, different types of cable etc).. and all other carriers offering ADSL have just opted to follow like sheep around the world in order to provide a "reliable" service.
If you are prepared to accept errors in the ADSL link, then the distance can be stretched quite a bit further than the theoretical maximum.
Theory and practice always differ - at least internode is trying to offer people a service of some sort - even if they only get 1Mbit downstream - all carriers should have done this from the start - but complaints from customers probably wouldn't have let them..
Look out if Internode have to pay $$$ to get the ULL service repaired before they can put DSL on it... now that will be interesting.