ZK KR500E Wiegand reader

RFID (Radio Frequency IDentification) is a remote data storage and retrieval system that uses devices called tags, cards, transponders, or RFID tags. The fundamental purpose of RFID technology is to transmit the identity of an object (similar to a unique serial number) using radio waves. RFID technologies are grouped into the so-called Auto ID (automatic identification). RFID tags are small sticker-like devices that can be attached or incorporated into a product, an animal, or a person. They contain antennas to enable them to receive and respond to radiofrequency requests from an RFID transceiver. Passive tags do not need internal power, while active tags do. One of the advantages of using radiofrequency (instead of, for example, infrared) is that direct vision is not required between transmitter and receiver.