The most widely used Mifare technology is currently TYPEA compliant. The difference between it and TYPEB lies mainly in the communication modulation mode between the card and the reader. Simply put, when the information "1" is indicated, the signal will have a gap of 0.2-0.3 microseconds. When the information is "0", the signal may have There may also be no gaps, depending on the information before and after. The advantage of this method is that the information is obviously different, the chance of being interfered is small, the reaction speed is fast, and it is not easy to operate by mistake; the disadvantage is that the energy may fluctuate when it is necessary to continuously increase the energy to the non-contact card.