Traditional telephone service uses copper wire to transmit communications signals. Verizon Fios, however, transmits signals using hair-thin strands of glass fiber and laser-generated pulses of light.
Model types of the Optical Network Terminal
When that light reaches your home or office through the Verizon network, it is converted into electric signals in a box, called the ONT, installed onto either the outside or inside of your location. That way, it can be "read" by your telephones and computers. Information that is sent from your location will be converted from electric signals to light inside the ONT.
Unlike traditional self-powered telephone service, your Verizon Fios service depends on your location's power source.
The ONT has a power cord that goes into your location through the ONT Power Supply Unit where it plugs into an existing standard electrical outlet.
Important: To ensure connectivity to the Verizon Fios network, make sure your ONT Power Supply Unit is plugged in at all times.
About your ONT Power Supply Unit (OPSU)
Your ONT requires electricity to operate all Verizon services provided on the Verizon Fios network. The OPSU supplies that power by connecting your ONT directly to an electrical outlet at your location.
Optical Network Terminal (ONT)
The OPSU contains a single indicator light that tells you if electrical power is present. If the indicator light is dark, electricity is not flowing from the outlet to the ONT. During normal operation, the light should be green.
The ONT requires very little power to operate. In fact, the amount of power needed is as little as what it would take to operate a couple of night-lights.
The ONT includes a Battery Back Unit (BBU) feature. You may utilize this feature by maintaining an active battery in the BBU. With an active battery, the BBU will provide backup power for your basic Fios voice services, including Emergency 911 dialing, for up to 8 hours in the event of a commercial power failure. 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 must be replaced. Please note that a damaged or leaking battery may damage Verizon network equipment and should be removed and/or replaced immediately.
Battery Backup Unit
The BBU is installed at your location in an area where it can be easily monitored - most likely near the ONT Power Supply Unit (OPSU). The BBU is connected directly to the ONT to provide backup power if it's needed. In addition, the BBU contains a series of indicator lights that tell you whether your service is being powered by your location's electricity or the battery (if one is installed in the BBU).
The BBU also indicates when the backup battery needs to be replaced.
How do I get a replacement battery?
Verizon supplied batteries are under warranty for one year. How long you've had your battery generally determines when a replacement is needed. Follow the guidelines here.
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 verizon.com/fiosaccessories 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:
Your BBU is equipped with an audible alarm to inform you of problems with your BBU. The alarm sounds for two seconds and then is silent for 58 seconds. The conditions listed below are the potential reasons for the audible alarm. You can use the alarm in combination with the indicator lights to troubleshoot your BBU issue.
Low Battery - Alarm is silenced if the battery voltage goes above 12V (electrical power has returned), the battery is fully discharged, or the battery is removed from the BBU.
Foreign Voltage - Alarm is silenced once the foreign voltage has been properly removed.
Replace Battery - Alarm is silenced when the battery is removed.
Overcurrent - Alarm is silenced once the overcurrent has been properly removed.
Since you are responsible for ensuring that a battery is installed and maintained in the BBU, it is very important that you familiarize yourself with the indicator lights and audible alarm to ensure that you have backup power if it's needed.
Please note: During a power outage, only your standard telephone service will receive power if an active battery is installed in the BBU. The BBU will not operate your Internet or video services, or your router. The BBU will shut down approximately one hour before that battery has completely drained. If you need to make an emergency phone call after the BBU has shut down, press the Battery Emergency Use button on the ONT. This should enable the ONT to reboot and provide up to one hour of talk time. After you press the Battery Emergency Use button, the BBU will operate until the battery has completely drained.