I'm aware that battery backups are optional when you first connect to the NBN (I opted out), but my question is can you opt out when changing over to a UNI-V service when you are already signed up and have an existing voice service through the Gateway Max.
I did contact Telstra, but they implied that you HAVE to have the battery back-up installed if you want to switch to UNI-V - but they lady I spoke to seemed unsure when pushed on the point.