The description of 125KHz & 13.56MHz Contactless Smart Card Reader.
Low frequency RFID system readers generally operate at a frequency range from 120 kHz to 134 kHz. The wavelength of this band is about 2500m, except for metal materials, the low frequency can generally pass through any material objects without reducing its reading distance. Low-frequency RFID systems use ID cards, known as Identification Cards, as their electronic tags. ID card is a kind of induction card that can not be written, its internal only stored data is a fixed ID card number, its record content (card number) is written by chip manufacturers before sealing card factory, sealing card can not be changed, developers can only read card number to be used. ID card and we use magnetic card normally same, used only “the number of card” just, besides card number inside card, without any confidential function, its “card number” is open, bare.
High frequency card reader is a card reader that works in the high frequency HF band. It generally works in the 13.56M frequency band. Sensors at this frequency no longer need coils to be wound, and antennas can be made by etching them alive and printing them. Inductor usually works by load modulation, that is, the voltage on the antenna of reader is changed by the switch on and off of the load resistor on the inductor, so as to realize the amplitude modulation of the antenna voltage by the remote inductor. If a person controls the load voltage on and off with the data, the data can be transmitted from the sensor to the reader.
