The listing, Voice Service / Phone Modem Battery Backup PEGATRON PB018A2 for DPC3939 DPQ Comcast DPC3941T has ended.
PEGATRON PB013 Upgrade to PB018A2 8 Hour Cable Modem Battery for DPC3939 DPQ Comcast DPC3941T
Buy a Phone Modem Battery for Your Voice Service!
Power outage? You'll need a backup battery to make emergency calls from your home phone. A backup battery will ensure your phone service remains available to you for up to 24 hours.
If you have any of the following, it is particularly important that you install the battery as soon as possible.
A home alarm system
A personal emergency alert device
A phone that is not cordless and will continue to work during a power outage
Another device that relies on your phone line for continuous operation
Voice service will not operate during a power failure without a backup power source.