Access control system manufacturers offer various scalable systems from as few as two credential readers to several thousand readers on a single system. Selecting the correct design largely depends on the number of credential readers required, application software complexity and system scalability. Generally, if the system requires just a few credential readers, it should not necessitate a complex software application. Small to medium systems, which handle from two readers up to around 64 readers, can operate on a simple desktop PC running a local application database.
Systems of 64 or more readers should use a more sophisticated and centralized server-style database application. The more readers on the access control system, the faster the application database software will be required to respond to the field hardware query requests and updates. Even though most systems are designed to provide autonomous control at the access control panel level, the access control server database still has to update each panel periodically with new or modified information from the application database. Data transfer speeds can slow considerably when attempting to update dozens of access control panels, especially during periods of heavy reader usage. A popular feature in newer systems is for the access control server to perform alarm monitoring. Because of this, each access panel progressively added to the system inevitably will reduce the system’s response time.