Battery Backup Options

Your Fios voice service is powered by an Optical Network Terminal (ONT). There are different types of ONTs. Depending on which ONT you have, your option for backup power is different. Your ONT is likely installed either on the outside of your home or in a utility closet inside your home. Please take a look at your ONT and follow along below to determine the backup power option for you.


Do you have a power adapter like this installed with your ONT?

If your ONT is installed with a power adapter that looks like this image, then your back up power option is a PowerReserve device. To order a PowerReserve device please visit the Fios Accessories store. It will be easy to install when you receive it. Directions will be included with your device.

For further information about the PowerReserve device, click here.

Battery Backup Unit

Does your ONT have a separate box installed with it that looks similar to this image?

If your ONT does not have a power adapter, then your ONT was installed with a Battery Backup Unit (BBU), which will look similar to the above image. Please note, however, that there are many models of BBUs, so yours may not look identical to this image.

If you would like to enable back up power, you simply need to install a 12-volt 7.2Ah SLA (Sealed Lead Acid) battery into your BBU. You can purchase this battery through Verizon at or you may purchase one from a third party vendor. If you choose to purchase your battery from a third-party vendor, please make sure that you are purchasing a 12-volt 7.2Ah SLA battery.

For more information about the BBU and 12-volt battery, click here.

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