What must all readers provide in case the unit fails?

All electronic access control systems are designed to ensure security and functionality, even in the event of a failure. The correct answer highlights the importance of having a means of bypass in place if a reader fails. This is crucial because it allows for the continued operation of a secured area without compromising safety.

In practice, if a card reader or biometric scanner goes offline, a bypass mechanism can enable authorized personnel to gain entry without relying on the malfunctioning electronic system. This could include physical keys, master control systems, or other manual entry methods. Ensuring a bypass capability maintains security protocols while providing a fail-safe option during emergencies or technical difficulties.

While backup power sources, manual reset options, and alternative signal connections could contribute to the overall reliability of the system, they do not directly address the immediate need for access in case of a reader failure. The primary concern during a failure is to ensure that authorized individuals can still enter the premises, which is achieved effectively through a bypass mechanism.