Radio frequency card and working principle of a basic introduction

First, briefly
RF Card also known as non-contact IC card, was born in the early 90s, is the world in recent years developed a new technology, it succeeded in radio frequency technology and IC card technology knowledge together to solve the passive (card in the non-power), and free access to this dilemma is the field of electronic devices a major breakthrough. Because the existence of magnetic card and contactless IC card incomparable advantages, so that by the advent of one, it immediately aroused widespread concern, and at an alarming rate to be popularized.
Non-contact IC card by the IC chip, sensing antenna, and fully sealed in a standard PVC card, no exposed parts. Non-contact type IC card reading and writing process, typically by a non-contact type IC card and reader via radio waves between the read and write operation to complete.
Non-contact type IC card itself is a passive body, when the reader to the card read and write operations, read and write the signal emitted from the stack composed of two parts: one is the power signal, the signal received by the card after his own L / C generated resonance, producing an instant energy to supply chips work. The other part is a combination of data signals, directing the completion of the data chips, modification, storage, etc., and returned to the reader. By a non-contact IC card reading and writing formed by the system, whether hardware structure, or operation have been greatly simplified, while the help of advanced management software, offline mode of operation, all the data read and write process easier.
And contact-type IC card compared to non-contact-type card has the following advantages:
1. High reliability: non-contact IC card and no mechanical contact between the reader and avoid contact with reading and writing due to a variety of faults arising. For example: As brutal card, non-card insert foreign objects, dust, or oil and other reasons leading to poor contact caused by the fault. In addition, non-contact non-exposed surface of the chip card, without fear of falling chip, electrostatic breakdown, bending damage and other issues, both for card printing, but also improves the reliability of the use of the card.
2. Easy to operate, fast: Due to non-contact communication, reader in the 10cm can be within the scope of the card operations, they do not have pluggable card, very convenient to use. Non-contact type card without direction, the card can be swept in any direction to read and write? Martingale grind?, To complete the operation, which greatly improves the speed of each use.
3. Anti-collision: Non-contact card in a fast anti-collision mechanism, to prevent interference of data between cards, so readers can "simultaneously" Dealing with more than one non-contact IC card. This has increased the application of parallelism, virtually to improve the system work faster.
4. Could be suitable for a variety of applications: non-contact-type card storage structural features make it a multi-purpose card can be used in different systems, users can set different depending on the application of the password and access conditions.
5. Encryption performance is good: non-contact card's serial number is unique, manufacturers of products manufactured prior to curing this serial number can not be changed. Non-contact between the card and reader using two-way authentication mechanism, namely, IC card reader verify the legitimacy of, when IC card reader also verified the legitimacy of. Non-contact type card reader before it is processed three times with mutual authentication, but also in the process of communication in all of the data are encrypted. In addition, the card operation in various sectors have their own password and access conditions? S take along the wall yo ナ inquire constraints C card has unparalleled advantages over, so it is very suitable for electronic wallets, automatic highway toll system and a bus automatic ticketing system.
2, Ml system parameters
Ml non-contact MIFAREI international standards in line with a capacity of 8K bits, data retention period of 10 years, can be rewritten 100,000 times, reading indefinitely. Ml card without power, comes with antenna, includes encryption control logic circuitry and communication logic, card and reader communication between the DES and the adoption of internationally accepted RES confidential cross-algorithm, has a very high security performance.
Operating Frequency: 13.56HMZ * Communication speed: 106HB Baud Rate
Anti-collision: at the same time can handle slightly more than one card read and write distance: In the 100MM in (with the shape of the antenna) can easily and quickly transfer the data * * half-duplex communication in the wireless communication process through the following mechanisms to ensure data integrity
Anti-collision mechanism • Each has a 16-bit CRC error correction • there is parity bit per byte • Check digits
Encoding method used to distinguish between "l", "0" or no information • channel monitoring (through the protocol sequence and bit stream analysis)
Multi-card operation
Anti-collision mechanism: the same time, can handle multiple cards, and cards when dealing with anti-burst read or write or read-write interruptions of a dynamic read and write when processing cards, other cards may enter or leave the radio frequency Regional Fast anti-collision protocols for each additional card to the whole process is increased by only 1ms
Material: PVC * Dimensions: compliance with ISO10536 standards * Working Temperature: 20 ℃ to 50 ℃ (humidity 90%) * No Batteries: Wireless way to pass data and energy * chip processing technology: use of high-speed craft * CMOSEEPROM components: a chip and a simple coil of security: • three mutual authentication (ISO / EC DIS97982)
3, the working principle
The electrical part of the card by only one antenna and ASIC component, there is no other external devices. Antenna: The antenna is only a few cards winding coil group, it is suitable for packaging into the ISO card. ASIC: Card of the ASIC by a high-speed (106KB baud rate) interface, a control unit and an 8K-bit EEPBOM composition. Ml RF card works are: Ml card reader issued to a group of fixed-frequency electromagnetic waves, the card has a LC series resonant circuit, its frequency and the frequency of launching the same reader, inspired by the electromagnetic waves, LC resonant resonance circuit, so that capacitor with the charge in this capacitor the other end then there is a single wizard-pass the electronic pump, the capacitor charge storage capacitor to another, when the accumulated charge to 2V, This capacitor can be used as power for other circuits to provide operating voltage, data transmission will be the card reader out of, or access data.
4, privacy
MI RF card security performance of good: to read and write before the three confirmed that the unique card serial number, transmission data encryption, transmission of the password and access password-protected. Card password is protected, unreadable, only users who know the password to modify. Card 16-bit EEPROM sub-sectors, each sector has its own reading of the password, users can set different passwords for different sectors, sector, and KEY A password is divided into two different passwords KEYB the two groups were restricted password reducing operating and processing operations.
5, the structure
MI RF card 8K-bit EEPROM is divided into 16 sectors, each sector from the four, each block of 16 bytes. Each of the four sectors in the block 3 (fourth block) contains the sector of KEYA (6 bytes), access control (4 bytes), and KEYB (6 bytes), the remaining three bits data block. In the 0-63, the 0 for curing blocks, including manufacturers codes and other special content.