Smart Cards -- map format standard credit card has an embedded processor and contact pads for supply and exchange with the reader. There may be a very high degree of security, but in the access control are very limited application.
Proximity (P roximity) card.
Read the package with the identifier occurs at a certain distance from the reader without direct contact. The most widely received identifiers with the established within the integrated circuit, which represents sufficiently sophisticated electronic device containing a total If the receiver, transmitter and a processor with memory, in which stored identification code. Inside the identifier is as antenna, with it comes data exchange between him and the reader in the radio frequency electromagnetic wave. It is this type of remote ID and was named Proximity (Proximity Cards, Rroh card, etc.).
Contactless system Access control works based on radio waves and allows implement contactless identification cards, and programmed in their code numbers. Most these systems operate in the range low frequencies (66-156 kHz). It allows you to read the code through materials such as clothing, bags, and wall. However, there are systems operating at higher frequencies, such as card firms Checkpoint (U.S.) operate at a frequency of 13 MHz.
An example is the technology Readers CARDAX SmartRgoh. It advantage of recent developments in the field of radio frequency identification signal (RFID), all the components Reader combined into one integrated circuit, providing thereby exceptional reliability and technical efficiency. The reader sends a pulse frequency of 134.2 kHz and a duration of approximately 20 ms. The signal receiving antenna reader, tuned to the same frequency.
Scheme receives the card, such , the energy stored by capacitor as a source supply. Card uses energy conservation for the transfer feedback SmartProx-reader. Total transferred 126 bits of data for the period 20 ms. They are the receiving antenna and decoded by the reader module. After sending the information, the capacitor is discharged and the device is ready for the next round of identification.
For the interaction between the card and the reader uses a frequency shift method of encoding (FSK) transmission signal between the frequencies of 134.2 and 124.2 kHz.
CARDAX SmartProx The system uses a protocol error detection, guaranteeing that the reader correctly identifies the user.
High level of security is also guaranteed by encrypted data transmitted from the reader interface, and protection from interference in the device. Date of publication: 21/07/2007
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