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  • Check the Battery Back-up Unit (BBU) for Power

    In addition to your ONT, your service has a Battery Back-up Unit (BBU)* that is located inside your garage or house. In case your ONT is accidentally unplugged – or in the event of a commercial power failure – your back-up battery will provide you with power for voice service for up to 8 hours if an active battery is inserted in the BBU.

    Your BBU was installed in a location in your home where it can be easily monitored. It contains a series of indicator lights that tell you whether your service is being powered by your home's electricity or the battery.

    Please note that in the event of a power outage, your back-up battery will not operate your Internet service, router, VoIP or TV Service. Only your standard telephone service will receive power.

    If you are experiencing trouble with your phone service, first check your BBU. The BBU light indicators are explained below.

    Click to Enlarge
    BBU Light Indicators Your BBU has light indicators to signify certain conditions as described below:

    AC Light
    AC Indicator: Green indicates that your BBU is operating normally. Yellow indicates the BBU is operating on battery power. If it is not lighted, check to see if the power cord is plugged in.

    Output Light
    Output Indicator: Green indicates the BBU is operating on battery power. Otherwise, the indicator will be dark.

    Battery Light
    Battery Indicator: Red indicates that the battery is not connected or the battery needs to be replaced. Otherwise, this indicator will be dark.
      If you are not experiencing a commercial power outage, follow the troubleshooting steps below. The light indicators explained above will help you determine if the BBU is receiving power.

    1. Check that the power cord of the BBU is plugged into an AC outlet.

    2. If your outlet is a Ground Fault Circuit Interrupter (GFCI), check that it has not been tripped. If it has, press the reset button.

    3. Check the fuse or circuit breaker to make sure your outlet is working. Reset the breaker or replace fuses if necessary.

    4. After taking these steps, re-check the AC indicator on the BBU to see if it is lighted. If it is, re-check for service.

    5. If it is not lighted, contact the Verizon Fiber Solutions Center.

    If you are experiencing a power outage and are experiencing trouble with your phone service, check the battery indicator on the BBU. Follow the steps below to check your battery.

    1. If the Battery Indicator is red, check your battery connection inside the BBU.

    2. If the Battery is properly connected but the light is still red, replace the battery in the BBU (see below).

    3. After taking these steps, re-check the battery indicator light. If it is still lighted, call the Verizon Fiber Solutions Center.

    If your light indicators are in normal status, complete the Optical Network Terminal test procedure.
    BBU Battery Replacement You are responsible for purchasing and/or replacing the battery in the BBU. Much like you would need to replace the batteries in a portable radio from time to time, periodically the BBU battery must be be replaced. Please note that a damaged or leaking battery may damage Verizon network equipment and should be removed and/or replaced immediately. The average life of a battery is between 2 and 4 years, depending on the average temperature of the environment.

    *Important Note The Battery Back-Up Unit is designed to use a 12-Volt 7.2 Ah SLA (Sealed Lead Acid) battery. Use of a different battery type is not recommended since other battery types may impact the performance of your FiOS services. Verizon is not responsible for damages which result from use of an improper battery. Batteries may be obtained at or at a third party retail vendor.

    How do I properly dispose of my old battery?

    Battery disposal standards and requirements vary by state. If you need to replace the sealed lead-acid battery in your backup unit, please check with the following Environmental Protection Agency (EPA) resources for proper disposal instructions:

    Visit or call the EPA directly at 1-202-272-0167.

    Verizon Troubleshooter

    You can use the Verizon Troubleshooter to diagnose the problem and request a repair if an issue is detected.

    Watch the online Verizon Troubleshooter tour

    See also: Related FiOS Phone Service topics
    Troubleshooter Tools
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    Many equipment problems can be fixed in less than
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    Make sure your equipment is plugged in and that the power is working in the rest of your house


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