The nbn is being rolled out across Australia with a requirement for a power supply to operate. Hence the nbn in your premises will not work in a blackout unless a battery backup supply is installed. This is the responsibility of the premises owners to ensure your equipment will work during a power outage. Especially if you rely on autodiallers, medical alarms and emergency call buttons. For example our Mode-3 IDC security connectors are utilised for alarm autodialler applications. Therefore before nbn installation you can register sensitive medical Alarm equipment with the NBN and check with your device provider.
The nbn website states "If you choose to have the nbn™ Power Supply Unit with Optional Battery Backup Service (pictured below) as part of your installation, it comes with the battery when it is first installed into a home or business. In the event of a power outage, your landline phone and internet services over the nbn™ network won’t work if the battery is faulty or missing".
Image courtesy nbn
Battery type: 12V 7.0-7.2Ah 6 Cell VRLA Sealed Lead Acid Battery Dimensions: 150mm (W) x 94mm (H) x 64mm (D) Terminals: Quick Disconnect F2 6.35mm (W) x 0.81mm (T) Faston®Tab terminals.
Battery World Australia sells replacement nbn batteries instore Ph 13 17 60
Source available: nbn battery backup information