What does a battery backup do in an alarm system?

A battery backup in an alarm system is designed to ensure that the system remains operational during a power failure. This is critically important for maintaining the security of the premises, as many alarm systems rely on continuous power to function effectively. If there is a power outage, the battery backup activates automatically, providing the necessary energy to keep the alarm system running. This feature is essential for ensuring that the alarm can still detect unauthorized entry and send alerts even when the main power supply is compromised.

The other options do not accurately represent the primary function of a battery backup. While additional security features, broadcasting signals, and sound quality enhancements may be beneficial for an alarm system, they do not relate to the fundamental role of a battery backup, which specifically addresses the need for power continuity.