What happens to access control doors if the network goes down?

Most access control readers store the list of users in the door controller, so doors keep working on the saved list when the network drops. New cards and changes will not reach them until the link returns, and event logs are held and uploaded later.

The door behaviour on a power or network failure should be decided at design time. Doors on escape routes must always release, while a store room may stay locked. A battery backup keeps readers and locks alive for a limited time.

Mount Everest Automatic Doors sets the fail-safe or fail-secure mode for each door. See access control systems for how a site is planned.