An access control system is a device that controls the entry, exit and flow of patrons at a premises. The access control system allows people to visit your business, notify people when your business is closed, control the flow of customers entering your business and provide other useful insights. Access control systems are common features at supermarkets, retail stores, offices and other businesses. While most access control system provide access to anyone, other intelligent access control system can limit access to those with secure access credentials (i.e. a code, fob or key card).