You may be required to replace the batteries for your device if your nbn connection box is installed with a Power Supply Unit with Battery Backup.
Your nbn connection box may be powered using a Power Supply Unit that includes a Battery Backup if your home is connected using Fibre to the Premises (FTTP) technology.
In these instances, the Power Supply Unit provides power to your connection box, with the Battery Backup designed to provide your connection box with backup power.
Make sure your Power Supply Unit is always plugged into an electrical outlet and avoid using extension cords or other secondary plug types.
In case of a power outage, the nbn also recommends keeping the power supply plugged in at all times to ensure the battery remains fully charged.