These are mounted near elevators and read the smart cards' credentials. When a user swipes his or her smart card, the reader captures the identification number of that particular card, and checks if the same user is allowed or not. Traditionally, smart card readers are most frequently used for the mentioned purpose.

It acts as a fundamental interface; the access control system is connected to the floor control mechanism of the elevator. It allows authorized people to select particular floors into the elevator, which enhances the security aspect of the building.

This is the central module that controls all such actions. The access control controllers authenticate all the user credentials and have some sort of policies that a specific user needs to undergo for gaining access to the elevator or denial of access. Such modules interact with other modules to allow or deny access to elevators.

In the case of an emergency, such as fire, this module acts like a key switch that over-rides all other access control operations and permits uncontrolled access to the elevator for evacuating people from the building.

This is the core of the system whereby user credentials are managed and access rules defined; it implements the policy to allow only specific users to access specific floors, while keeping a record of all activities for security audits.