Sean Wicks
Past editions of this column have included a number of technical discussions concerning system components, peripheral devices and application software inherent in an access control system. Generally these topics apply to the design process after several key issues have been discussed with the client. Understanding the specific application requirements of an access control system’s electronics can prove vital in designing a system that is both serviceable and cost-effective.

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.

Server-based systems provide greater flexibility in the types of credential readers that can be integrated and managed by an access control application. Smart card technology has allowed the security industry to store a variety of information on a miniscule computer chip. Placed in a card or other personal item, the chip can be used for a number of applications, potentially reducing operating costs. For example, by storing monetary balance information on an access card microchip, the end user could conceivably use the same card to gain entrance to security portals through the access control system and to purchase lunch in the company cafeteria.

Integrating biometrics

Another component to consider in the early system design phase is biometric reader technology, which is already widely available and should only increase in popularity in the next few years. Access control system manufacturers recognize the benefits of this technology and are integrating formerly stand-alone biometric reader application software into the application database of their access control systems. This level of integration provides a single credential management database and easy enrolling.

Alarm point management sophistication is also a factor when choosing a design basis system. Most medium- to high-end systems offer an alarm management tool to annunciate and control alarm points. How, when, and who views and responds to the alarm are issues to consider when designing a system. On large-scale systems – those that are spread out over a campus or multiple cities with multiple monitoring locations – alarm management can become quite a task. The end user may want to monitor alarms locally at separate facilities during normal business hours, but during non-business hours, transfer the alarm monitoring from each local facility to a centralized location without user intervention.

Scalability becomes a real issue when this level of sophistication is applied to an access control system design. Careful consideration and planning are required to develop a system solution that produces a cost-effective, user-friendly design that can be managed, upgraded and expanded without difficulty.