What's the common problems and solutions of the access control system-part 1?

The access control system has always been an important part of the security system. There are a lot of access control issues every day, most of the access control issues are related to the details and frequently appear in the actual project. One may encounter this issues no matter it is a novice or an expert in access control system. Today, let’s know more about the access control issues and troubleshooting to those frequently appeared problems in the actual projects of the access control system.

1),  In the access control system, how to effectively prevent anti-trail?

Answer: Anti-trailing has always been the most difficult access control problems to solve in the access control system. It’s also the most frequently appeared problems in the actual project and must be solved in all the access control system projects as it's one of the primary functions of the access control system. There are several suggested ways to solve this access control problem:

1. Change the door: install the speeding door (or three roller gates). This way also has its shortcomings. For example, speed-pass door basically used in indoors with a width of 55cm. It only allows one person to pass, also it’s with counting alarm function. If two people pass through the door at the same time, then an alarm occurs. The three roller brakes can be used in outdoors, but for those who cross over from above, the prevention effect is not ideal. The three roller brakes are suitable for places such as the exhibition meeting with security guards.
2. Install an access control card reader. If a person follows the cardholder to enter and want to come out, he must also punch the card to open the door, so as to achieve the purpose of anti-tail. However, if the person follows the cardholder to enter and go out at the same time, an access card reader also cannot achieve the purpose of anti-tail.
3. Two-way reading card plus double door interlocking. Double door interlocking can basically solve the problem of trailing. As to open the second door, the first door must be locked, otherwise, you are not able to open the second door. A more troublesome way is to install the cameras. It uses image processing technology to detect portraits after the camera has captured images. However, this way is quite troublesome as it requires a lot of knowledge.
4. If you are with a high-security level, you can use full-height doors or more advanced interlocking door (two doors, the person enters a post weigh, then the second door open). This way can realize anti-tail, but these doors are quite expensive.

2). Is the host an extension of different brands compatible with each other?

Answer: This problem is frequently mentioned in our VIP group of the low voltage industry network.  A lot of people ask if it’s compatible when changing brands in halfway. Actually, it’s not compatible. For the host, as the wiring way and agreement is different, it's quite impossible to compatible unless you have the bottom agreement of the two manufacturers.

Different manufacturers have different intercom products. The market doesn't have a uniform standard, so it's not compatible for different brands. Therefore, we must use a same brand host and extension in the actual project and must pay attention to it when we purchasing equipment. Many novices will have this problem and cause failure to the following projects.
3). When the management machine talks to the door machine, the microphone of the door machine screams, how to deal with this access control problem?
Answer: It is likely that the wires are not connected properly. The normal condition is that there each piece of power supply line and G line, and the G line is connected one piece more. Another possibility is that the sound is not adjusted appropriately.

4). How to troubleshoot if one can’t open the door by intercom extension?

Answer: This is an access control problems frequently mentioned by many users, but they are not able to describe it in detail which categorizes into failure to describe in details. We suggest that the users must try to describe the problems as detailed as he can so that we can give the corresponding answers. If the problem is not specifically described, the possible faults may be: the electric control lock is broken, the signal is unstable or the wires of the electric control lock is not connected well. Also, you can check whether there are problems with the circuits.

Another fault may be the extension is broken. If you can open the door by other extensions of the same system, it means that their access control problems with the host line or the electric control lock is broken. It can also be not able to open the extension if the transient voltage provided by the unit door machine which offers to the electric control lock is not strong enough. You can also check the unlock button of the extension to see whether it’s broken or not. The last possibility is that there’s something wrong with the codes.

5). An old deaf man in an old reconstructed community who wants to install a bell with a lamp from the extension to remind himself to open the door when someone ringing the bell downstairs. Does it work and how to connect the wires?

Answer: The signal of ringing can be used to transform the circuit and lead the trigger signal to the circuit of the electric bell and the lamp through the relay switch. Turn the contacts switch into a double contact switch, and when the button is pressed, there is a free dry junction signal, which drives the visual signals such as flashing lights or ringtones.

6). For the old-fashioned direct view interphone， there must be no objects close to the back of the host, otherwise, there will be a beeping sound, why?

A: This is a typical speaker and microphone self-excitation phenomenon. Generally, the wave transferred by the speaker touch the objects, the sound waves will be sent back thus generate self-excitation phenomena. The fault cause is that the speaker is too sensitive. You can change a potentiometer and try to adjust the speaker’s sensitivity and make the lower the speaker's sound. You can also adjust the microphone's sensitivity and change the direction for testing. You can solve out the problems after adjusting the equipment.

7).  The community cell door is not connected to the internet, and the access control is from China while the interphone is from Taiwan. We want to control the cell door lock with the door machine and access control, but the engineers think that is not good to control the lock, is that true?

A: Just a simple switch signal will work. It should be okay if you own both of the two systems and install a relay. I take the access control as primary, you can connect the open signal wires of the interphone to the open button of the access control without a relay. What you need to do is to install a simple triode switch circuit to control the switch of the original intercom system which can avoid mutual interference.

8).   If installed an access control system in building A and also installed another branded access control system in building B, both of them operate individually. Whether there’s a possibility that the user can use the IC card/ID card of building A to open building B’s door and the functions of building A remain unchanged? 

A: Theoretically it’s okay to do so, it depends on the access controller. But first, you need to figure out what kind of card you are using. For example, intelligent cards, ID cards or encrypted cards.

9).  There are murmurs in the building host, and the noise is too loud to hear the voice of the visitors. Is it a power supply problem? If so, what should we do? If not, how to avoid it?

A: You should take the intercom system brand and the model of wiring into consideration, and more important is to find out where the interference comes from. It is likely that the aging power device interferes with the harmonic. You can try to change a good stable voltage power phase filter to have a test. The best solution is to update the power supply and then check the grounding is in a good connection.

10).  What are the differences between the IC card and ID card?

1. The definition of an IC card and ID card

The full name of IC card is Integrated Circuit Card, also called Smart Card. It’s read-write, with large capacity and encryption function, high data recording reliability and it’s convenient to use., such as E-card system and POS system. The Millfare serial cards of PHILPS is a typical application.
2. IC cards need to be initialized (i.e, encryption) while ID cards no need to do so.

While using the IC card, only when the IC card passes the particular two-way key authentication between the IC card and the read-write equipment it can work. In this way, it can improve the security of the whole system

Therefore, it’s necessary to initialize the IC cards (i.e. encryption) before factory. The purpose is that to make the IC card generates an unbreakable self-transferred system key to ensure the security mechanism of the IC card system. When the IC card is initially encrypted and given to the user for use, the customer will get a private key of his IC card system through the IC card issuing system. Therefore, it can make sure that those user cards issued by other systems will not work at this system, which guarantees the specificity of the system and ensure the system’s safety using mechanism.

11).  Why is the initialization not able to carry out by the users?  This is because:

1. If it’s initialized by the user, it can’t prevent the user from being cheating internally. Because when the user using the IC card system, and the staff use a card buy from irregular shops to initialized, then he can issue a resident card which only for household, moreover he can use the card to recharge and consume. This will not only cause serious cheating consequences but also result in loopholes in the IC card system security mechanism.
2. Security: The IC card is much safer than the ID card. Reading card number in the ID card needs no permissions and it’s easy to copy. It must have a corresponding password authentication when read and write all the recorded data in the IC card. Even each area in the card has a different password protection to protect overall data security. The user can set a different password to read and write the data of the IC card, which provide a good classification management to ensure system security
3. Recordability: Data cannot be written to the ID card. The record content (card number) can only be one-time written by the chip manufacturer. The developer can only read out the card number to use, but not able to formulate a new number management system based on the actual needs. The IC card can not only be able to allow the user to read out a large amount of data, but also authorize the user to write in a large amount of data (such as a new card number, user permissions, user data, etc.), The content of the IC card can be wiped over and over again.
4. Storage capacity: the ID card can only record the card number; while the IC card (such as Mifare card of Philips) can record about 1,000 characters.
5. Offline and networked operation: As there is no content in the ID card, the permissions and system functions of the cardholders must be fully supported by a database of computer network platform. While the IC card itself carries a large amount of user relative information (card number, user data, access information, consumption balance), it can completely get rid of the computer platform and realize the automatic transformation of the online and offline operation mode, which achieves a wide range of use and less wiring.
6. One-card expansion application: As the ID card has no record, no partition and only has to rely on the network software to process information of each subsystem, which greatly increases its dependence on the network. If the user wants to add more functions after the ID card system is completed, additional wiring is required, which not only increases the difficulty of construction but also increases unnecessary investment. So, it’s difficult to carry out the system expansion and realized the real one-card system by using ID card.

The IC card storage area itself is divided into 16 partitions, each partition has a different password and with several sub-management functions, such as the first partition realized the entrance guard, the second partition is for consumption, the third partition is for the employee’s attendance and so on. IC card can completely be realized the purpose of one-card and it’s able to realize the completely modular design. Even if the user wants to add more functions, there are no needs for additional wiring. What he only needs to do is to add hardware and software module, which is more convenient for the extent and upgrade the IC card system, with the stable upgrade but the less duplicate investment.

 12).  For parking lot, what is the distance from the farthest reading card for a passive M1 card?
A: The reading distance of the M card mainly depends on the power of the card reader, the speed of data exchange and it's frequency modulation. Without the antenna, the sensor is about 3-5 meters away from the antenna, which can reach up to 8 meters after the antenna is added. Currently, the M1 card cannot be read of a long distance in the case of no source.

 13).  What is the output format of the card reader?

A: The frequently used output formats of the card reader are: RS232, RS485, WG26, WG34, ABA. The ABA code for ID (also known as Manchester code) has the following two common types:

1. If the card reader adopts a hexadecimal system in 8H format, the ABA code is “192D9D”, and it is converted into a decimal code of “0026226077”.
2. If the card reader adopts a hexadecimal system in 6H format, the ABA code is “92D9D”, and it is converted into a decimal code of “0026226077”, converted into the hexadecimal system in 8H format is “1902D9D”, and converted into a hexadecimal system in 6H format is “902D9D”. This is also the reason why the ABA code read by the card reader is different from the ABA physical code on the card.

 14).  Put the card close to the card reader, the buzzer doesn’t ring and the indicator light doesn’t respond, but the communication works, where is the problem?

A: Possible reasons: (1) Incorrect connection between the card reader and the controller. (2). The length between the card reader and controller exceeds the effective length (120M).

 15).  What is the reason that with an effective card close to the card reader, the buzzer sounds once and no reaction for the LED lights, but not able to open the door?      Possible reasons:

(1). The incorrect connection between the card reader and the controller.

(2) Affected by serious interference, the data from the card reader fails to convey to the controller

 16).  The access controller has been working well, but suddenly all the valid cards are not able to open the door (turning into invalid cards)

Possible reasons:

• . The operator has the rest day setting (all the cards cannot be used to open the door on the rest day)
• .  The operator initialized or incorrectly set the access control system causing the controller to perform initialization commands.

 17).  Put a valid card close to the card reader, the buzzer rings and LED light turns green, but not able to open the door.

Possible reasons:

• The incorrect connection between the controller and the electric lock.
• Whether the power supply to the electric control lock is normal (the electric lock requires an individual power supply)
• Electric control lock faults
• The locking tongue and the latch are mechanically jammed

18).  Put a valid card close to the card reader, the buzzer rings and the lock open, but the indicator light not bright.

A: (1)  The controller and the electric control lock share the same power supply, which reversely interferes with the lock, resulting in the resetting of the controller. (2) The power supply is not enough to support the controller and the card reader to work in normal condition.

A: Currently multi-chip wiring is the mainstream. The video is transmitted by coaxial cable and audio, data and power supply are usually transmitted by RVV line or the network cable.

There are three problems need to be solved in the building intercom system: audio quality, video quality, and data transfer quality. The audio transmission has a triple wire system and double wire system. The triple wire system transmission can better solve the problem of signal amplification and adjustment.
 19).  What kind of wire should be used in an 8-story building? The triple wires or the N+1 wires?

A: It depends on the specific configuration, mainly related to the demand function of an intercom. Whether the intercom is visual or non-visual, it’s straightforward or coding or household intercom. It varies from different functions and models.If have no selected brand, the wring scheme suggestion is: Visual: 6 cores+1 videos; Non-visual: 4 cores. 

The above 20 problems the most frequently appear problems in the access control system. Of course, there are other problems, too. Mastering the solution methods of these kinds of problems will provide ideas and methods when you encounter other problems.

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