When a credential is presented to an access control system, its reader sends the credential’s information, to a control panel, a highly reliable central processor. The master type readers have such a control panel built into it, so does not rely on a external control panel. The control panel compares the credential’s number to an access control list, grants or denies the presented request, and sends a transaction log for storage into a software database. When access is denied based on the access control list, the door remains locked. Such access control denial events can be programmed to trigger various alerts and logs, including sirens, SMS alerts, photo, or video capture.