The access control system can be divided into the following three categories according to the way of access identification:
1. Password identification: identify the access authority by verifying whether the password is entered correctly.
This kind of products can be divided into two types: ordinary type and disordered keyboard type (the number on the keyboard is not fixed and changes automatically from time to time).
Normal type:
Advantages: easy operation, no need to carry cards; Low cost.
Disadvantages: Only three groups of passwords can be accommodated at the same time, which is easy to leak and has poor security; No entry and exit records; Only one-way control.
Disordered keyboard type (the number on the keyboard is not fixed and automatically changes irregularly):
Advantages: easy operation, no need to carry cards, slightly higher safety factor
Disadvantages: The password is easy to leak, and the security is still not high; No entry and exit records; Only one-way control. High cost.
2. Card identification: identify the access authority through card reading or card reading plus password, which can be divided into:
·Magnetic card
Advantages: low cost; One card for one person (+password), general security, computer connection, door opening record
Disadvantages: card and equipment are worn and have short service life; The card is easy to copy; It is not easy to control in both directions. Card information is easily lost due to external magnetic field, which makes the card invalid.
RF card
Advantages: cards and equipment are contactless, and the door opening is convenient and safe; Long life, theoretical data at least ten years; High safety, computer connection, door opening record; It can realize two-way control. The card is difficult to copy
Disadvantages: high cost
3. Portrait recognition: identify the entrance and exit by means of biometrics of inspectors. There are fingerprint type, iris type and face recognition type.
Advantages: excellent security from the perspective of identification; No card required
Disadvantages: high cost. The recognition rate is not high, the requirements for the environment are high, and the requirements for users are high (for example, the fingerprint cannot be scratched, the eyes cannot be red, swollen, bleeding, the face cannot be injured, or the number of mustaches). It is not convenient to use (for example, the iris type and the face recognition type, the installation height and position are fixed, but the height of the users are different)
It is worth noting that most people think that the biometric access control system is very safe. In fact, this is a misunderstanding. The security of the access control system is not only the security of the identification method, but also the security of the control system, software system, communication system, and power system. For example, some fingerprint access control systems controller It is integrated with the fingerprint identification device, and should be installed outdoors when installing, so that the wire controlling the lock switch is exposed outdoors, which is easy to be opened.
The access control system can be divided into the following two categories according to the design principle:
1. The controller has its own card reader (identifier)
The defect of this design is that the controller must be installed outside the door, so some control lines must be exposed outside the door, and professionals can easily open the door without cards or passwords.
2. The controller is separated from the card reader (identifier)
This type of system controller is installed indoors. Only the input line of the card reader is exposed outdoors, and all other control lines are indoors. The card reader transmits digital signals. Therefore, no one can enter the door without a valid card or password.
Such systems should be the user's first choice.
The access control system can be divided into the following two categories according to the communication mode with microcomputer:
1. Single machine control type
This type of product is the most common, applicable to small systems or units with centralized installation locations. RS485 communication mode is usually adopted. Its advantages are small investment and dedicated communication lines. The disadvantage is that once installed, it is not easy to change the location of the management center, and it is not easy to achieve network control and remote control.
2. Network type
This kind of product has high technical content, which is rare at present. Only a few companies have formed their products. Its communication mode adopts the TCP/IP protocol commonly used in the network. The advantage of this kind of system is that the controller and management center transfer data through the LAN, and the management center location can be changed at any time without rewiring, so it is easy to realize network control or remote control.
It is suitable for large systems or units with scattered installation locations. The disadvantage of this kind of system is that the stability of the communication part of the system depends on the stability of the LAN.
