NBN Co has said that Telstra will provide "refreshed information" on the state of the legacy copper network as the company begins using that network for fibre-to-the-node services.
As part of the revised AU$11 billion agreement between the two companies, NBN Co will take ownership of the copper and hybrid fibre-coaxial (HFC) networks as the rollout progresses to the so-called multi-technology mix version of the National Broadband Network (NBN).
Under the previous agreement, NBN Co paid Telstra for access to the ducts and pipes, and for transferring customers onto the fibre-based NBN, but not the legacy technology itself.
Since the Coalition first announced its intention to build out fibre to the node and use existing HFC networks in April 2013, questions have been raised over whether the two networks would be up to the task of delivering at least 25Mbps to all Australians, and what costs NBN Co would face in maintaining the copper and HFC components of the multi-technology mix NBN.
In a response published this week to a question from the Senate Select Committee on the NBN, NBN Co explained that the company had evaluated the Telstra copper and HFC networks in a "desktop-based due diligence" process prior to signing the agreements late last year.
NBN Co said that this process identified the assets and looked at detailed planning information, ownership of the assets, operational information, the number of HFC lead-ins, spectrum management, historical maintenance costs, and disputes.
For the copper network, NBN Co was provided with cable plant records, technical specifications on sheath types, gauges, attenuations, and crosstalk characteristics, and information on pair gain systems in the network.
"Information on Telstra's complete network will be included in the long-term planning for NBN," the company told the committee.
"Additionally, NBN Co will receive refreshed information periodically during the planning and design phases."
ZDNet has sought additional comment from NBN Co on whether the company engaged any external due diligence process outside of the "desktop-based" process.
As NBN Co CEO Bill Morrow has previously indicated, the company is not obligated to use the legacy technology in its network if it is more cost effective to use fibre.
"In addition to the due diligence, NBN Co can -- at its discretion -- adjust the mix of technology within a region to ensure the lowest cost of implementation by taking into account the specific circumstances within a region," the company stated.
The company's new rollout model will get under way over the next few months, with HFC due to come online in 2016. NBN Co also revealed that those customers on the fibre-to-the-node trial would continue to have free access to the service until a commercial product is released in the third quarter of this year.
Customers on fibre-to-the-basement (FttB) also appear to be the happiest on the network, with NBN Co stating that end-user satisfaction surveys came back at 8.4 for FttB, versus 7.1 for fibre to the premises and 8.1 for fixed wireless.
In response to another question regarding how a Coalition MP gained access to time frames around when construction on the network will start in her electorate before the information was made public, NBN Co said it would provide information to the public on construction start dates on a quarterly basis.