The access control system is a kind of security system in the intelligent weak current system. As a new type of modern safety management system, it integrates automatic identification technology and modern safety management measures, involving many new technologies such as electronics, machinery, optics, computer technology, communication technology, and biological technology. The access control system installs door magnets, electric locks or controllers, card readers and other control devices at the main entrances and exits of buildings, elevator halls, equipment control center machine rooms, valuables warehouses and other important departments. The management personnel monitor in the central control room, and can control the position of each passageway, passage object, passage time, direction, etc. in real time or set program control, so as to control people’s entrance and exit.

The access control system is conventionally composed of an access controller, an access card reader, a card, an electric lock, an access control software, a power supply and other related access control equipment.

Access controller: The access controller is the core part of the access control system. Its function is equivalent to the CPU of the computer. It is responsible for the processing, storage and control of the input and output information of the entire system. It verifies the reliability of the input information of the access control card reader, and judges its validity according to the access rules, and if it is valid, it sends an action signal to the execution component. The performance of the access controller directly affects the stability of the system, and the stability of the system directly affects the safety of customers' lives and property.

Access control card reader: Read the data and biometric information in the card, and transmit these information to the access control controller.

Card: The electronic key for opening the door of the access control system. This "key" can be a magnetic card, IC card, ID card and other related function cards (the card can print the cardholder's personal photo, and the door opening card and the badge are combined into one).

Electric control lock: The executive component of the access control system. The electric control lock is usually open when the power is off to meet the fire protection requirements. It is equipped with a variety of installation structure types for customers to choose. According to different technical requirements such as one-way wooden doors, glass doors, metal fire doors and two-way electric doors, different types of electric locks can be selected.

Access control software: it is responsible for the monitoring, management, and query of the access control system. Managers can complete patrol, attendance, and personnel positioning etc. through adjustments.

Power supply and other related access control equipment: The power supply support the energy for the entire access control system, and it is an important component (if the access control system has no power supply, the entire access control system will be in a paralyzed state). Other access control equipment, like the exit button, you can press it once then the door opening device will be open, exit buuton is suitable for situations where there is no restriction on going out; Take the door sensor as another example, it is used to detect the door’s safety/opening status etc.

At present, foreign-produced access control systems are relatively safe, but they are expensive. The price of inductive access control system controllers ranges from 4,000 to 30,000 yuan, including a set of card readers, door locks, controllers, and software. The price is above 10,000 yuan. The price of domestically produced inductive access control system and fingerprint access control system is about 10%-50% lower than that of similar foreign products, but the reliability of the system is slightly lower.

The access control system developed rapidly with the development of automatic identification technology. At present, the research and usage of access control systems in China and other countries are mainly concentrated in sensor access control systems and biometric access control systems. In biometric access control systems, fingerprint access control systems are the most widely used. With the continuous development and maturity of computer image processing and pattern recognition theory and large-scale integrated circuit technology, the volume of the fingerprint automatic identification system is continuously shrinking, and its price had also continuously reduced. In 2002, fingerprint recognition accounted for nearly 50% of market and iris recognition accounted for 8%. In 2005, fingerprint recognition accounted for nearly 40%, and iris recognition accounted for about 10% of market. In the next few years, the trend of rapid growth will still be maintained. When we review the development of access control market, we can expecte that the average growth rate of China's access control market will reach more than 20% in the next 1-3 years.

The advanced intelligent access control system is an important development direction of the access control system in present. The advanced intelligent access control system is a networked access control system with relatively complete functions. However, it is not the most ideal choice for general enterprises and residential communities. This kind of access control system is often used in national defense, military and other units.

With the rapid popularization and development of computers, more and more control devices are gradually replaced by computers, the monitoring and maintenance of maintenance personnel are becoming more and more concentrated, and more and more control systems are gradually becoming intelligent. Due to the development of computer networks, equipment can be monitored and maintained through a center or through an endpoint. Monitoring and maintenance equipment in local region by the local area network can improve the reliability of the system and reduce the incidence of failures and save processing time.