20 key knowledge answers about access control systems

1. How can the effective implementation of anti-tailing in the access control system?
A: Anti-tailing has always been a difficult problem for access control systems. The following are recommended:
Change the door: add a speed gate (or three roller gate). This method also has its shortcomings. Like the speed-pass door, it is basically used indoors. The width is only 55cm. Only one person is allowed to pass, and there is a counting alarm function. If two people pass at the same time, an alarm will be generated. The three-roller can be used outdoors, but for those who cross from above, the preventive effect is not ideal, and the three-roller is suitable for places such as security guards.
2) Install the card reader in and out. If a person follows the cardholder's entry, if you want to come out, you must also swipe the card to open the access door, in order to achieve the purpose of anti-tailing. However, when going out, if the trailing person also goes out with the cardholder at the same time, it can not achieve the purpose of true anti-tailing.
3) Two-way card reading plus two-door interlocking. The double-door interlocking method can basically solve the trailing problem, because to open the second door, the first door must be locked, or the second door cannot be opened at all. There is also a more cumbersome method to install the camera, which is to use image processing technology to detect the portrait (after acquiring the image through the camera), but this method is more troublesome and requires a lot of knowledge extension.
4) If the security level is particularly high, you can use a full-height or higher-level interlocking door (two doors, the person enters a weight and then the second door opens) to achieve true anti-tailing; the disadvantage is that the price of such doors is not Philippines.
2, the intercom extension can not open the door, how to troubleshoot?
A: The fault description is not detailed. If you provide a more detailed fault description and electrical schematic, you can give an clearer answer. Therefore, the following can only provide several kinds of faults that may exist: it may be that the electronic control lock is broken, the signal is hesitant or the line contact of the electric control lock is not good. In addition, you can also check if there is a problem on the household line;
Another possibility is that the extension is broken. If other extensions on the system can't open the lock, it means that the main line of the system has a problem or the electric lock is broken. If the instantaneous voltage supplied to the electric lock by the unit door machine is not reached, the extension may not be opened; the button of the extension unlocking may also be checked to detect whether it is broken; the last one may be an error in the encoding.
3. When the management machine and the door machine talk, the microphone of the door machine screams. How to deal with this problem?
A: This phenomenon may be improper wiring. The normal situation is that the power supply and the G line are each one, and the G line is connected one more; the other may be that the sound adjustment is not appropriate.
4. Can the host and extension of different brands be compatible with each other during community maintenance?
A: It is impossible to be compatible. For the bus, because the wiring method and protocol may be different, the compatibility may be almost zero unless the bottom-end protocol of two manufacturers is found.
At present, there are basically no standards for visual intercom products. Products from different manufacturers cannot be interconnected, and video intercom subsystems cannot basically be interconnected with other weak electronic systems. The reason is that there is no standard. Without standards and lack of openness, the system cannot be interconnected, and the warranty and service of the products cannot be guaranteed for a long time, and the industry cannot develop healthily. Therefore, the market is very much looking forward to the emergence of standardized and open products.
5, an old community renovation project has a deaf grandfather, want to get from the extension and a lighted bell, when the call downstairs lights to remind the door to open, I do not know how feasible and how to wire?
Answer: The signal can be achieved by using the ringing signal. The circuit is modified and the trigger signal is led to the circuit in which the bell and the lamp are connected in series through the relay switch. Turn the contact switch into a two-contact switch. When the button is pressed, an idle dry node signal is sent to drive a visual signal such as a flash or ring tone.
6, the community unit access control is not connected to the Internet, the access control is Shenzhen Chuangtong products, the intercom is Taiwan products. Now it is necessary to control the unit door lock together with the unit door machine and the unit access control, but the intercom engineering party thinks that it is not good to control the door lock, is this the case?
A: Just a simple switch signal, if both systems are done, it should be no problem, plus a relay can be solved. If it is based on the access control, you can connect the open door signal line of the intercom to the door open button of the access control, and no relay is needed. Add a simple triode switch circuit to control the unlock relay of the original intercom system, so as to avoid mutual interference.
7, the old-fashioned direct press video intercom host, can not have any objects close to the back of the host, otherwise there will be beeping, what is the reason?
Answer: The typical speaker and microphone are self-excited. Generally, the sound waves transmitted by the speakers are close to the object, and the sound waves are transmitted back to generate self-excitation. The cause of the fault is that the sensitivity of the speaker is too high. Try to adjust the sensitivity of the speaker and adjust the sensitivity of the speaker. Adjust the sensitivity of the microphone, debug the direction of the microphone, and solve the problem by adjusting the device.
8. A set of access control is installed in a certain ground building. If a different brand of access control is installed in the second building, the two sets of access control will operate independently. Can I use the IC card (or ID card) for access control in the B building, and the access control function of the building will remain unchanged?
A: In theory, it is just a problem with the access controller. But first of all, to figure out what card was used, such as some companies' smart cards or identification cards, some are dedicated cards, and some are encryption cards.
9, the building intercom host has a noise, the extension noise is too big to hear the voice of the coming. Is it a problem with the power supply? If so, what should I do? Not what? How can this problem be avoided?
A: This should consider what brand of intercom system, as well as the model of the wiring selection line. What is more important is to find out where the interference comes from. It may be that the harmonics caused by the aging of the power supply device can be changed first. Try to filter the power supply with good phase filtering. The best solution is to update the power supply. The other is to see if the ground wire is in good contact.
10. What is the difference between an IC card and an ID card?
Answer: 1) Definition of IC card and ID card:
The IC card is called the Integrated Circuit Card, also known as the Smart Card. It can be read and written, has large capacity, has encryption function, reliable data recording, and is more convenient to use, such as card system, consumer system, etc. Currently, there are mainly Miifare series cards of PHILPS.
ID card full name identification card (Identification Card), is a non-writable proximity card, with a fixed number, mainly Taiwan SYRIS EM format, the United States HID, TI, MOTOROLA and other ID cards.
2) The IC card needs to be initialized (ie, encrypted), and the ID card does not need to use the IC card when it is used. It must first pass the unique two-way key authentication between the IC card and the reading and writing device before the related work can be performed. The system is extremely secure.
Therefore, it is necessary to initialize (ie, encrypt) the factory IC, in order to generate an unbreakable card system key in the IC card after leaving the factory to ensure the security release mechanism of the card system. After the IC card is initialized and encrypted, when it is delivered to the user, the customer issues a system through the IC card issuing system, and each user card generates a private key of its own system. In this way, it is ensured that the user cards issued in other user systems cannot be used in the system, thereby ensuring the specificity of the system, thereby ensuring the safe use mechanism of the system.
Like the magnetic card, the ID card only uses the "card number". The card has no security function except the card number. The "card number" is open and bare. Therefore, the ID card is an "inductive magnetic card", and the main problem is that the main need does not need initialization.
Why is the initialization process not left to the user? This is because:
1) If it is initialized by the user himself, it cannot prevent the internal staff from cheating. Because when the user is using the card system, if an employee uses the card bought by the society to initialize it at will, he can freely issue the resident card that the resident can use, and even recharge the card at will, which will not only cause serious cheating consequences, but also This will lead to serious security holes in the use of the card system.
2) In addition, if the user buys a poor quality factory card to initialize itself and cannot be used on the system, the system performance may be poor or flawed, which will result in unclear responsibility for the accident.
3) The initialization process is performed at the manufacturer, mainly the basic needs of the IC card security key authentication mechanism, and also the profile of the IC card system integrator. Just like the city public transport IC card, before the card is used in the bus system, the key of each card must be factory-encrypted.
4) If the user lacks professional management and loses the key card for initial authorization, the user and the manufacturer will not be able to replenish the card. Therefore, the initialization work is done by the manufacturer, and there is security.
11. Comparison of IC card system and ID card system 1) Security: The security of the IC card is much larger than that of the ID card. The card number in the ID card is read without any permission and is easy to copy. The reading and writing of the data recorded in the IC card require corresponding password authentication, and even each area in the card has different password protection, which fully protects the data security. The password of the IC card to write data and the password for reading data can be Set to different, provide a good hierarchical management to ensure system security.
2) Recordability: ID card can't write data, its record content (card number) can only be written by the chip manufacturer once, the developer can only read the card number and use it, can't formulate new number management according to the actual needs of the system. system. The IC card can not only read a large amount of data by an authorized user, but also can write a large amount of data (such as a new card number, user's authority, user data, etc.) by an authorized user, and the content recorded by the IC card can be repeatedly erased.
3) Storage capacity: The ID card only records the card number; and the IC card (such as the Philips mifare card) can record about 1000 characters.
4) Offline and networked operation: Since there is no content in the ID card, the card holder's authority and system function operation can completely depend on the support of the computer network platform database. The IC card itself has recorded a large amount of user-related content (card number, user data, permissions, consumption balance, etc.), which can be run away from the computer platform, and realizes the operation mode of networking and offline automatic conversion, which can achieve a wide range of uses. Less wiring requirements.
5) One-card expansion application: ID card has no record, no partition, and can only rely on network software to process the information of each subsystem, which greatly increases the dependence on the network; if the Id card system is completed, the user wants to add function points. , additional wiring is required, which not only increases the difficulty of construction, but also increases unnecessary investment. Therefore, using an ID card as a system makes it difficult to expand the system and it is difficult to implement a real card.
The IC card storage area itself is divided into 16 partitions, each partition has a different password, and has multiple sub-systems * management functions, such as the first partition to achieve access control, the second partition to achieve consumption, the third partition to achieve employee attendance, and the like. . Fully realize the purpose of the card, and can achieve a completely modular design. Even if the user wants to add function points, there is no need to re-route, just add hardware and software modules, which facilitates the IC card system to upgrade and expand at any time to achieve a smooth upgrade. , reducing duplication of investment.
6) Maintenance and operation of intelligent systems:
For example, if a computer releases a new user ID card, it must be able to pass the ID card system network and manually download all ID card numbers one by one to each ID card reading controller. Otherwise, the ID card is used as a countless card. Cannot be used; to change user permissions, enter the ID card number with permission on each ID card controller.
Another example is to add an ID card after the system is put into use. If you add a card every year or modify the permissions of a card, you must enter the card number on the controller that is available for the card. It greatly increases the workload and time of manual operation and maintenance; in addition, if there are more than one card subsystem, or the subsystem is slightly larger, the complexity of system maintenance management will increase geometrically, which will directly lead to the system not working properly. run.
The card system using the IC card, after the IC card is issued, the card itself is a data information carrier. Even if the communication network is unreachable, the read/write controller can realize the offline read/write card operation as usual; if the user authority is changed, the user authority can be directly Written in the IC card, new users can change the permissions only need to modify the card, no need to modify each controller, from the technical mechanism to avoid the manager to change the authority of the controller card everywhere, to improve management efficiency To achieve the purpose of intelligent management.
7) Value for money:
Although the ID card and its card reader are cheaper than the IC card and its card reader, the price of the two systems is comparable to that of the entire card system (wiring cost, structural composition), and the IC card system is more than the ID card system. The operation is stable and reliable, so the cost performance of the IC card system is much higher than that of the ID card system.
In addition, considering that the hardware environment of today's community is not very mature, and the system personnel are not familiar with the computer knowledge, it is impossible to establish or maintain a complete network system to support the 24-hour continuous operation of the ID card card. Therefore, the smart IC card card system that meets the needs of networking and offline operation is a better choice for today's users.
12. What is the farthest reading distance of the passive M1 card used for parking?
A: The distance of the M card mainly depends on the power of its reader, the speed of data exchange and its frequency modulation. The passive card has a sensing distance of about 3-5 meters without an antenna, and can be up to 8 meters when the antenna is added. At present, in the case of passive, the M1 card can not read the card at a very long distance.
13. What are the output formats of the card reader?
A: The commonly used card reader output formats: RS232, RS485, WG26, WG34, ABA. There are two common types of ID ABA code (also known as Manchester code):
1) If the card reader adopts the hexadecimal notation in 8H format, the ABA code is "192D9D" and the decimal code is "0026226077".
2) If the card reader adopts the hexadecimal notation in 6H format, the ABA code is "92D9D", and the ABA code is converted to "0009448861". In decimal notation "0026226077", the hexadecimal converted to 8H format is "1902D9D", and the hexadecimal converted to 6H format is "902D9D". This is also why the ABA code read by the card reader is different from the ABA physical code on the card.
14. Move the card close to the card reader, the buzzer does not ring, the indicator light does not respond, and the communication is normal. What's the problem?
A: Possible reasons: (1) The connection between the card reader and the controller is incorrect; (2) The card reader to controller line exceeds the effective length (120M)
15. When the valid card is close to the card reader, the buzzer will sound once, the LED indicator light will not change, and the door cannot be opened. What is the reason?
A: Possible reasons: (1) The card reader and the controller are not connected correctly; (2) The line is seriously disturbed, and the card reader data cannot be transmitted to the controller.
16. The use of the access control device has been normal. On a certain day, all valid cards cannot open the door (become invalid).
A: Possible reasons: (1) The operator has set a rest day for the access control device (all cards cannot be opened on the rest day);
(2) The operator has initialized the access control or other reasons cause the controller to execute an initialization command.
17. Move the valid card close to the card reader, the buzzer sounds, the LED indicator turns green, but the door lock is not open?
A: Possible reasons: (1) The connection between the controller and the electronically controlled lock is incorrect;
(2) Whether the power supply to the electric lock is normal (the electric lock requires a separate power supply);
(3) The electronic control lock is faulty;
(4) The lock tongue and the lock are mechanically stuck.
18. When the valid card is close to the card reader, the buzzer will sound once, the door lock will open, but the card reader light will be off?
Answer: (1) The controller and the electric control lock share a power supply, which is the reverse potential interference during the lock operation, resulting in control reset; (2) The power supply is not enough, causing the controller and the card reader to fail to work normally.
19. What are the main wiring structures of networked building intelligent systems?
Answer: Nowadays, the multi-core cable is mainly used as the mainstream mode. The video is transmitted by coaxial cable. The audio, data and power are usually transmitted by RVV cable, and the network cable can also be used. Such as Shenzhen Matsumoto Smart (4+1 way), Xi'an Kaiyuan, Shenzhen Shidean, Xiamen Lilin, Guangzhou Anjubao, etc., and other manufacturers use two-wire signal modulation transmission, there are also wireless products.
In the wiring of the building intercom system, three problems need to be solved: audio quality, video quality, and data transmission quality. The audio transmission has a 3-wire system and a 2-wire system. The 3-wire transmission can better solve the problem of signal amplification and adjustment.
Data transmission generally uses a dedicated codec chip, CAN transceiver and RS-485. The differential data transmission method has advantages in signal anti-interference such as RS-485. The baseband electronic flat mode transmits the guest data and is highly susceptible to the bus mode. It is divided into dry bus (networking) and branch bus (unit), which are connected by router (separator).
20. What kind of wire should be used for the 8th floor building intercom? Three-line and N+1?
A: It depends on the specific configuration requirements. It is mainly related to the demand function of the intercom. The intercom is visual or non-visual. It is straight-through or coded or the intercom of the household. The functions are different and the shape will have Subtle differences.
If no brand is selected, the wiring proposal: visible: 6 core +1 video; non-visible: 4 core.