Telecom New Zealand is set to roll out ADSL2+ broadband services later this year, offering speeds of up to 15Mbit/s for download, dwarfing today's maximum of 2Mbit/s over Telecom's copper lines.

ADSL2+ is the new standard for Digital Subscriber Lines about to be ratified by the International Telecommunications Union. Telecom's technology partner, Alcatel, is already assessing the product for the New Zealand market and Telecom hopes to start trials of the technology in the middle of the year, says Telecom chief technology officer Murray Milner.

"We would look to rolling out the new DSLAMs to the cabinets later this year with a view to offering faster services by the start of 2006 or even as early as the end of this year."

One of the big issues facing Telecom is the existing installed DSL modem base. Milner wants to make sure most if not all existing models are capable of functioning fully on the new DSLAM network.

"There are bound to be the odd one or two that don't function and we'll have to work through that issue if and when we come to it."

Initially Telecom will use the ADSL2+ equipment to continue offering the services available at the moment, but Milner says new services will come on stream quickly, although no firm service levels or price points have been established yet.

"There are benefits to be had simply from rolling out the DSLAMs themselves. Better traffic handling, further reach and so on, as well as faster speeds." While ADSL2+ can offer speeds of up to 20Mbit/s, Milner says in New Zealand for the Telecom network that speed is likely to be up to 15Mbit/s download and 1Mbit/s up.

"We run a cabinetised network so distance from the cabinet is all important, but typically most homes are within 800m to 1,000m of a cabinet so they should see up to 15Mbit/s."

In Australia iiNet is also planning to launch ADSL2+ services via its unbundled access to Telstra's copper network. IiNet will roll out around 100 ADSL2+ DSLAMs as soon as the standard is ratified and founder Michael Malone says his goal is to provide 20Mbit/s service to residential customers.

Telecom's approach will mirror that of its T3G cellphone network rollout, says Milner.

"We'll start off with a geographical approach, upgrading some exchanges and offering service there before expanding to other areas, rather than trying to build out the entire country first before offering any new services."

Milner is also keeping an eye on another DSL variation - very high bitrate DSL (VDSL), which is expected to offer speeds of up to 52Mbit/s Â- to see whether it will be a viable replacement for ADSL2+ when the time comes to upgrade again. "VDSL may become the preferred standard by 2007," Milner says.

Telecom is currently evaluating a number of other technology options, including fibre to the home, to see what choices it has for the years ahead.

All of this work dovetails with Telecom's next generation network project which will see the incumbent spend $1 billion over more than a decade upgrading the fibre backhaul capacity of the network.

"The intention is to build out fibre to the cabinets and then make use of the copper network from cabinets to the premises."

Milner says the end certainly isn't in sight for the existing copper network - far from it. "There's a lot of copper out there in use today and so long as there's plenty of it about there will be people doing R&D into how to make better use of it," he says.