Introduction to several classification methods and advantages and disadvantages of access control systems

The access control system can be divided into the following three categories according to the access identification method:
1. Password identification: Identify the access rights by verifying that the password is correct.
These products are divided into two categories: one is a common type, and the other is an out-of-order keyboard type (the numbers on the keyboard are not fixed, and they are automatically changed from time to time).
normal type:
· Advantages: easy to operate, no need to carry cards; low cost.
· Disadvantages: At the same time, it can only accommodate three sets of passwords, which are easy to leak, and the security is very poor; there is no entry and exit record; only one-way control.
Out of order keyboard type (the number on the keyboard is not fixed, it changes automatically from time to time):
·Advantages: easy to operate, no need to carry cards, slightly higher safety factor. · Disadvantages: passwords are easy to leak, security is not high; no entry and exit records; only one-way control. high cost.
2, card recognition: by reading the card or reading the card plus password to identify the access rights, according to the card type is divided into:
Magnetic card · Advantages: low cost; one person and one card (+ password), safe in general, can be connected to the microcomputer, has a door opening record. Disadvantages: cards, equipment wear and tear, short life; cards are easy to copy; Card information is easily lost due to external magnetic fields, making the card invalid.
RF card ·Advantages: Card, equipment without contact, easy to open the door; long life, theoretical data for at least ten years; high security, can be connected to the microcomputer, there is a door opening record; can achieve two-way control. Cards are difficult to copy. Disadvantages: high cost. 3. Portrait recognition: Identification of entry and exit by means of inspecting biometrics. There are fingerprint type, iris type, and face recognition type.
·Advantages: Excellent security from the point of view of the identification; no need to carry cards. Disadvantages: high cost. The recognition rate is not high, the environment requirements are high, and the user requirements are high (such as fingerprints can not be scratched, the eyes can not be red and swollen, the face can not be injured, or the amount of beard), inconvenient to use (such as iris type and facial recognition) Type, the installation height position is certain, but the user's height is 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, the security of the software system, and the security of the communication system. The security of the power system The whole system is a whole, and the whole system is not safe. For example, some fingerprint access control systems, its controller and fingerprint reader are integrated, and should be installed outdoors when installed, so that the line that controls the lock switch is exposed outdoors, and it is easy to be opened.
The access control system can be divided into the following two categories according to the design principle:
1. Controller comes with a card reader (identifier)
The drawback of this design is that the controller must be installed outside the door, so some of the control lines must be exposed outside the door, and the pedestrian can easily open the door without a card or password.
2. The system controller of the controller and the card reader (identifier) ​​is installed indoors, only the card reader input line is exposed outdoors, all other control lines are indoors, and 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 the microcomputer:
1. Stand-alone control This type of product is the most common and is suitable for units with small systems or installation locations. RS485 communication is usually used. Its advantage is that the investment is small and the communication line is dedicated. The disadvantage is that once installed, the location of the management center cannot be easily replaced, and network control and remote control are not easy to implement.
2. Network type The high-tech content of these products is still rare, and only a few companies have formed products. Its communication method uses the TCP/IP protocol commonly used in the network. The advantage of this type of system is that the controller and management center transfer data through the LAN. The location of the management center can be changed at any time without rewiring, and it is easy to implement network control or remote control.
Suitable for use in large systems or units with dispersed installation locations. The disadvantage of this type of system is that the stability of the communication part of the system depends on the stability of the local area network.