If the power to an alarm panel goes off, the panel will not be able to function and the alarm system will not be able to send signals to the monitoring station. Additionally, any wired sensors or devices connected to the panel will also not function. If the panel has a backup battery, it will continue to operate for a limited time until the battery is drained. Some alarm systems also have cellular backup, which allows them to communicate with the monitoring station even if the landline or internet connection is down.