All voice service installations include a battery backup free of charge. This backup makes it possible for your corded, landline phones to work in the event of a power outage. In emergency situations, this will allow you to call 911 from your corded, landline phone. The battery backup is expected to last up to eight hours in the event of an outage depending on the battery age, usage and the environment. The batteries are rechargeable, but should be replaced every five to ten years. Extended backup batteries, which last up to 24 hours, are available for purchase. If you are interested in purchasing an extended battery, please contact our office.