Access Control Reader Selection Guide

Access control card reader, generally referred to as "access control reader" or "reader". As a very important part of the access control system, its importance is no less than that of the access controller.

So, how to choose the most suitable access control card reader for the project? Here is a summary of years of experience in product selection in the access control industry to enhance the competitiveness of the domestic access control industry.

First of all, I would like to introduce the classification of card readers to you. Because there is no national standard for access control card readers, the classification methods have not been unified. To sum up, there are mainly the following classification methods:

1. According to the type of card reading: the traditional cards used in access control mainly include EM (ID) cards and MF1 (IC) cards, corresponding to what we usually call ID card readers and IC card readers. However, in recent years, with the crackdown on MF1 (IC) cards and the continuous progress of RFID technology in social applications. Below, we analyze the essential differences between such cards in access control applications.

a. Choose from security requirements: At present, the application of access control card readers EM cards, MF1 cards, second-generation ID cards, RF-SIM cards, bus cards, citizen cards, residence permits, etc. are generally read in sequence Numbers. In theory, the security level is the same. However, ID cards, etc. will generally not be lent. Copying ID cards is a very serious matter in nature, so it is relatively safe to swipe a card with an ID card. To really prevent the card from being copied technically, the most secure one should be the CPU card. Because the CPU card comes with a CPU chip in the card, the content of each card can be privately encrypted, which is very difficult to crack. At present, the cards and card readers that require "national secret algorithm certification" in many government confidential projects are CPU cards and CPU readers. However, the cost of a CPU card is N times that of an ordinary ID or IC card, so you must pay attention when calculating the cost.

b. Choose from the convenience of using cards: At present, due to the rapid development of RFID technology, many users have been surrounded by various cards. For users, if one card can be used to handle all system applications, the convenience is very attractive. Generally speaking, in the application of the one-card, if there is an application of the consumption part, it is more convenient to select the IC on the reading head of the access control. Because many cards in the consumption part still use IC cards. This facilitates the application of the card. In addition, for social applications, and some projects that are inconvenient to reissue cards on a large scale, when selecting a card reader, it is necessary to choose an access control card reader that can read the second-generation ID card and residence permit, so as to ensure Most people can use their existing documents as access control card readers.

2. According to the communication mode: the communication mode of the card reader mainly refers to the communication between the card reader and the controller. Generally divided into two kinds of WIEGAND and RS485.

Let's talk about WIEGAND communication first. At present, most of the access control communication types are WIEGANGD (hereinafter referred to as WG). WG communication is divided into WG26, WG34, WG66, etc. The difference between them lies in the number of digits in the reading card number (WG66 is longer than WG34, and WG34 is longer than WG26). The longer the card number is read, the heavier the card number transmitted. The less likely it is.

In the industry, there are generally more card readers of WG26 and WG34. At the same time, the communication of the card reader also needs the corresponding controller to correspond. That is to say, if it is a WG34 reader, the card reader interface of the controller must also be To be able to support WG34 access. My suggestion is that the access control card reader and the access control controller should be produced by the same manufacturer as much as possible, and there is no need to worry about the appearance of duplicate numbers for items with ordinary WG34 readers. The WG66 reading head is mainly used for super-large projects, such as the card reading application of the second-generation ID card for national applications, and the card reading application of bank cards nationwide (requiring to read the 18-digit card number of the bank card). At present, there are not many domestic manufacturers that can read WG66, and Max has released WG66 Access controllers.

Compared with WG communication, RS485 communication has a long transmission distance (1200 meters), and the other is that it can use fewer lines to transmit a variety of different signals. Four lines (power +, power -, 485+, 485- ) can transmit the card number, transmit anti-tampering, tamper-proof signals, and can feedback information from the controller to control LED (light) and BEEP (buzzer), etc. Generally speaking, when the 485 reading head is deployed on the occasion of online patrol (in this case, it only needs to read the card and does not need accessories such as control locks), its communication distance is very advantageous.

3. According to appearance and material: size (large, medium, small), material (metal, plastic).

The reason for such classification is that in our actual projects, in addition to functional requirements, many users have requirements for the appearance of access control card readers, because most users themselves do not know much about access control technology. Deep, in the case of meeting basic needs, users pay more attention to the card reader that they see every day. To put it bluntly, it is its appearance and texture. From the working principle of the card reader, the general access control card reader is very sensitive to the metal shield, so most of the card readers are made of plastic shells.

In addition, the size of the card reader is mainly determined according to the installation conditions on-site, especially when it comes to the installation of the glass wall. Usually, the position for installing the card reader will be very narrow in this case, so special attention should be paid when selecting the type.

4. Classification for product reliability: At present, the card readers on the market can be divided into high-reliability access control card readers and general access control card readers. The main reason for this classification is that the reliability of the access control card readers on the market varies greatly. The cheapest access control card readers can be bought for 30 to 50 yuan and the high-end access control card readers cost thousands of yuan each. Also, they all open the door by swiping the card. Why is there such a big difference? The reason why there is such a situation in the access control card reader market is that apart from the difference in brand positioning, reliability is the watershed of their grades. 

The reliability of the access control card reader is mainly reflected in the following aspects:

a. Port protection: Because the installation of the card reader will involve wiring (power lines, signal lines, etc. at least 4~6, as many as ten), during the construction process, it is inevitable to connect the wrong wires Yes if the port is not protected, the card reader will be damaged, which will bring a lot of trouble to the engineering company, so when choosing a product, you must choose an access control card reader with port protection function. The specific identification method is in the case of 12V Next, carry out tests such as reverse connection, wrong connection of power line, short circuit of power supply and signal line, etc. If the reverse connection and wrong connection can last for more than 30 minutes, and the card reader of the device is not damaged, then the quality is acceptable.

b. Wide voltage design (drive capability): Mainly consider the problem of voltage drop of the power supply when the card reader is wired for a relatively long distance. If the card reader is 100 meters away from the controller), the card reader cannot work normally. Generally speaking, the card reader can work normally at a voltage of 7~30V, and its voltage adaptation range is relatively complete. The test method is also very simple, just use the adjustable power supply to connect the power cord of the card reader to test. Or use a 100-meter network cable to connect the reading head and the controller directly to see if it works normally.

c. Anti-interference: mainly refers to some occasions, the card reader must inevitably be installed on the surface of the metal object (iron door, stainless steel door), and there is another situation where the card is swiped in and out. The headers need to be installed "back to back". If it is a product with weak anti-interference, when it is installed on the surface of a metal object, the card reading distance will be significantly reduced, or even no card will be read. However, if the products installed "back to back" are not strong in anti-interference, it is very likely that the card reader will be sensed when the card is swiped when entering the door. This is very inconvenient to use. The judgment method for anti-interference is very simple, that is, when choosing a card reader, find an iron plate, stick the card reader on the iron plate, and see if the reading distance changes. It is recommended to choose the IC reader for testing. (IC card reading distance is generally 3~5CM). The other is to connect two card readers, place the two card readers side by side with a distance of no more than 5cm, and then swipe the cards on the card readers to see if there is a "serial number".

5. Regarding whether the access control card reader is filled with glue and its high and low-temperature performance.

Glue filling is very good for the moisture-proof and damage-proof of the card reader. Generally, it is recommended to choose glue filling for the access control card reader. However, glue filling means higher requirements for circuit design and product reliability. One is that the power consumption of the card reader design should not be too high. If the power consumption is high, glue filling is not conducive to heat dissipation. The other is that there are also requirements for the glue-filling process. In actual projects, the card reader must inevitably be installed outside the city. In addition to being waterproof, it has a wide range of adaptability to height and stability. Due to the possibility of being exposed to sunlight during the day, coupled with the environmental differences between the northern and southern regions of the country, the temperature difference between day and night in many places will also be large. The principle of specific card reader selection is to give priority to the glue-filled access control card reader, and in the process of selecting the glue-filled reading head, it is necessary to add a test for high and low temperatures. Generally speaking, the access control card reader with a temperature adaptability range of -40 degrees Celsius to 85 degrees Celsius can meet the application of most occasions. The specific test method can be tested with the help of some low-temperature boxes and high-temperature boxes.

6. Regarding anti-dismantlement and tamper-proof.

Generally, the reading head output by WG does not have the anti-tampering and anti-tampering function, but this function is required in some applications. One way is to directly add a "detection switch" on the reading head and then lead the signal line out. This method is relatively simple, but it needs to consider whether there is a signal interface on the controller that is tamper-proof and tamper-proof. Another solution is to judge directly through the WG signal, which adds a heartbeat signal to the WG output of the access control card reader to judge whether the connection between the card reader and the controller is normal. More convenient, I recommend it.

Author: Written by Anna Zhang from S4A INDUSTRIAL CO., LIMITED