The card reader emits electromagnetic waves at a fixed frequency, and the frequency is generally 13.56 MHz. When the proximity card enters the wireless access control system map in the electromagnetic radiation range of the card reader, the coil on the induction card is triggered, thereby generating current and triggering the induction. The antenna on the card transmits a signal to the card reader. This signal carries the card information. The card reader converts the level signal into a digital serial number and transmits it to the local controller. The local controller uploads the information to the upper layer. The controller is finally uploaded to the access control server, and the access control server compares the card number with the information in the database to obtain all the card information.
When choosing the access control card reader, pay attention to the following:
1. Selection of reader materials:
We recommend that you use a non-sealed card reader, because even if the seal is installed, the buzzer is exposed to the outside, and if it enters the water, it will damage the card reader. The material used for sealing is resin. Most of the domestic use of manual sealing and curing agent is uneven. The domestic resin material is cheap but the quality is not good. It will be conductive after long time use, causing the card reader to run chaotic or crash. Imported resins are expensive and domestic manufacturers generally do not use them. In addition, the sealant is not suitable for heat dissipation of the device, which will have a certain impact on the performance of the card reader.
2. Don't judge the quality from the appearance alone:
It should be judged from the use time and repair rate of the manufacturer's card reader for more than half a year, the manufacturer's quality standards and word of mouth. In addition, the card reader is a device that is used for a long time. In the circuit design, it must be protected by a circuit that is anti-crash.