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Troubleshooting Your Battery Backup Unit

The Battery Backup Unit (BBU) and the Power Supply Unit (PSU) are required for FiOS® and Vantage™ Voice by Frontier® services to the Optical Network Terminal (or ONT).

  • Each Battery Backup Unit must have a Power Supply Unit that plugs into an outlet, supplying power to it.
  • Each Power Supply Unit has a small green light on it. If it's illuminated, it has power. If not, it's not receiving power.
  • To determine if the PSU is receiving power, try testing the outlet with a lamp or hair dryer. This can easily determine if the outlet is supplying power.

Did you notice an intermittent beep coming from the Battery Backup Unit? This means it needs attention. Please note—even though there are different BBU models, the lights on BBUs are basically the same.

To test the battery for possible replacement:

  • First remove the leads connecting to the BBU.
  • Then unplug the Battery Backup Unit from the AC power outlet.
  • Wait 30 seconds and then plug it back in to AC power.
  • Wait for the BBU to start beeping, indicating it's not getting battery power.
  • Then replace the battery by firmly re-attaching the leads and placing it back in the housing unit.

The FiOS® marks are owned by Verizon Trademark Services LLC and used under license.

Still need help? Call 1.800.921.8101 or Live Chat

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