But still no word on a national rollout.

Telstra has completed an upgrade of its hybrid fibre coaxial (HFC) cable network to the DOCSIS 3.0 specification, to allow download speeds of 100 Mbps and uploads of 2 Mbps.

But the carrier refuses to speculate when it might roll out the same technology to the rest of the nation.

Holly Kramer of Product Management said the network upgrade, which will be switched on as of December 1, makes Telstra's Melbourne cable network Australia's "fastest HFC network".

Telstra had announced the upgrade - which uses DOCSIS 3.0 (Data Over Cable System Interface Specification) - in March, and had promised it would be completed before Christmas. The company said the upgrade cost less than the $300 million originally forecast.

Almost one million homes in Melbourne are within the range of the HFC network should they wish to take up the service. No pricing details were released.

Kramer said the network was so fast "it exceeds the capabilities of most PCs and servers" today, but said "people will still want to experience" the speeds. Kramer said it was online video consumption was becoming a "daily ritual" in the home, with home users interested in consuming web pages, video and internet gaming at the same time.

Kramer and several colleagues from Telstra took a few questions from the press after the announcement, but cut the Q&A session short after journalists repeatedly asked how the cable network upgrade impacted negotiations with the Federal Government over the National Broadband Network or when Telstra would take the high speed cable network to other capitals.

"We haven't made the call yet on when or where and how [the cable network might be rolled out nationally]," Kramer said. "We'll see how it goes."

Kramer insisted that the threat of competition from an NBN fibre rollout was "not the reason we have done [the upgrade]."

Another Telstra executive on-hand at the announcement said Melbourne was chosen for the trial for good reasons.

"Melbourne is very competitive in broadband, and most [Telstra's] design and engineering capability here in Melbourne," he said. "It allows us to test and evaluate how this will really go in terms of technology and the market."

Announces set-top box

Telstra used the completion of the cable network upgrade to spruik a new product under development, a dual-tuner set-top box that streams BigPond's online content to the television.

Dubbed the T-Box, as distinct from the T-Hub announced at the Telstra Investor Day, is essentially a standard set top box that gives users access to an electronic program guide, allowing users to pre-record, pause and rewind/fast-forward free to air TV.

Where the T-Box differs to other Set Top Box options is the integration of BigPond's online content - some seven channels of television content and a movie download service - all a subset of the far richer content offered through Pay TV company Foxtel, which is partly owned by Telstra.

Kramer said the service was "complementary to Foxtel", in that content on the T-Box will be "primarily free to air and web-based content."

The T-Box will be offered for trial to customers on Telstra's high speed cable network in Melbourne next month.

But in a slip-up that suggests Telstra has no plans to take its HFC cable upgrade national, a Telstra executive said the T-Box might also be offered to the carrier's ADSL2+ customers in other capitals later next year.

Correction - this article originally stated Telstra would introduce speeds of 200 Mbps on its Melbourne HFC cable network. This figure was misheard during a conference call with very poor audio! Our apologies for the confusion.