Telstra is offering its first voice product on the National Broadband Network operating via the UNI-V port on the network termination device.

A spokesperson for the telco confirmed the nature of the product to iTnews, after it was noticed by users of the Whirlpool forum on July 30.
A critical information summary (pdf) accompanying the product, which is known as T-Voice Standard, indicated it would "be delivered via the NBN and will be battery backed-up by the NBN Co supplied power supply unit and battery".
Battery back-up is used for phone services that connect through the UNI-V port on the network termination device (NTD), according to an NBN Co FAQ.
A Telstra spokesperson said T-Voice Standard would be "offered to voice-only customers moving onto the NBN".
"The product operates on the UNI-V port of the NBN Co Connection Box, and offers battery back-up in the event of a local power outage," the spokesperson said.
"By plugging directly into the NBN Co Connection Box [NTD], it simplifies the installation experience, negating the need for an additional gateway device.
"Customers on a NBN voice and internet bundle will continue to receive a T-Voice Advanced voice which is delivered over the UNI-D port using a Telstra Home Network Gateway."
The NBN Connection Box or NTD contains two UNI-V (voice) ports and four UNI-D (data) ports. Phone services can be delivered via either port.