Firefly Fiber Broadband Battery Backup for VoIP Service

Backup Power for Residential Fiber Optic Voice Telephone Services During Power Outages:

For many years, your landline telephone would allow you to stay connected to emergency voice services during a power outage. However, if your residential voice telephone service is provided using fiber optics, fixed wireless, or by coaxial cable, rather than the traditional twisted pair copper-based line, the residential voice telephone service requires backup battery power to continue functioning during a power outage. To avoid a disruption of home voice service during a power outage—and to maintain the ability to connect to 911 emergency services—Firefly offers customers a battery for backup power for your residential fiber optic voice telephone service at the time of the initial installation for $4.99 per month. 

What Your Backup Battery Can and Cannot Do for You:

The backup battery for fiber optic voice service allows you to continue to use your voice services during a power outage. Without a backup battery or alternate backup power source such as a generator, customers with fiber, fixed wireless or coaxial cable delivered services will not be able to make calls, including emergency calls to 911.  The only way to maintain the ability to use your voice service is by using some form of backup power.  The backup battery is designed to only keep the voice service up for a certain duration; it will not power other ports or your Wi-Fi router. 

Inability to Use Cordless Phones and Other Devices During a Power Outage:

If you have a cordless phone, it will not work during a power outage as your cordless phone requires power from an external power source like an electric outlet in your home. To use your cordless phone, you would need to power the cordless phone with a backup generator or UPS (Uninterruptible Power Supply). To use your Firefly’s Voice service during power outages, we suggest that you keep a corded phone on hand. Corded phones, unlike cordless phones, do not need a separate power source to operate.

Firefly’s backup battery only provides backup power to Firefly’s fiber optic voice services. Devices that rely on voice service, such as home security systems, medical monitoring devices, TTY devices, and other equipment may be disrupted if there is an electrical power outage unless those devices are powered by an alternate power source such as a generator or UPS (Uninterruptible Power Supply). These type of alternate power sources are available from third party retail vendors.

Expected Backup Battery Power Duration:

The backup battery included with your Firefly’s fiber optic voice service is expected to last up to 24 hours on standby power. The backup battery should give you approximately 8 to 10 hours of talk time. 

Instructions for Proper Care and Use of Your Backup Battery:

Your backup battery is installed at or near the Firefly Fiber Optic Network Terminal “ONT” inside your home. The battery for your Firefly’s fiber optic voice services is designed to be operated in temperatures above 14°F and below 120°F. Firefly’s backup batteries are rechargeable and have an estimated useful life span of 6-10 years. Firefly advanced electronics monitors the battery voltage and will alert us when it is low. You will not need to access the battery, however if you experience any problems with your Firefly fiber optic voice service during a power outage of less than 24 hours, please promptly notify us. Firefly will provide and install at no cost to you, a replacement backup battery. If you have any questions, please call (833) 473-3591, or email

For a printable version of this policy, click here.

Reviewed: 6/27/2022