The long-distance range reads the card

　　At present in the market said the long-distance range reads the card usually is aims at the non- contact type IC card to say, the usual situation knowledge reads the distance is about 10CM is called the long-distance range to read the card. But in the massive applications, in particular the automatic diagnosis and in the data acquisition domain all requests the long-distance range to read the card range coverage to be possible to adjust in 0 ~ several dozens meters scopes. The most typical application is the vehicles automatic diagnosis like ETC highway does not stop the charge, its request long-distance range reads the card to be able to know reads in at least ten meters distances. Says by the present technical method, only then two ways can realize: One kind is uses half active electronic label the long-distance range to read the card, the knowledge reads the distance to be able to amount to ten meters; Another kind is uses the active electronic label (active radio frequency card) the long-distance range reads the card, the knowledge reads is away from far may amount to 100 meters. These two kind of long-distance ranges read the card important difference to lie in the knowledge to read the reliability: Half active radio frequency card long-distance range reads the card capacity and experience to read the reliability not to be able to achieve 100%, but the active radio frequency card long-distance range reads the card reliable performance to obtain the complete guarantee. Certainly, latter support electronic label cost also correspondingly is higher than former. Therefore, reads the card regarding the long-distance range choice to be decided by the application demand.

　　The typical long-distance range reads the card to contain has the high frequency module (transmitter and receiver), the control unit as well as the long-distance range reads the card antenna. In addition, many long-distance ranges will read the card also to have the attachment the connection (RS232, RS485, the ethernet connection and so on), in order to will obtain the data will pass on to the application system or from the application system receive order.

　　The electronic label and the long-distance range read the card constitution the radio frequency recognition system is in the final analysis serves for the application, the application demand possibly is many and varied, various. The long-distance range reads the card and between application system connection API (Application Programm In-terface) passes the commonly used group to be possible by the application system development kit (for example VC++, VB, the standard connection function which PB and so on) transfers to express. The standard connection function function includes following four aspects approximately.
　　1)the application system according to needs possibly to read the card to the long-distance range to send out the long-distance range to read the card disposition order.
　　2)the long-distance range reads the card all possible long-distance ranges which possibly returns to the application system to read the card current disposition condition.
　　3)the application system reads each kind of order to the long-distance range which the card possibly transmits.
　　4)the long-distance range reads the card possibly to return to the application system all possibly orders to carry out the result.
　　 The consummation radio frequency recognition technical standard also includes the long-distance range to read the card and between the application procedure standard connection stipulation. For example: ANSI NCITS256—2001, the IS018000 series radio frequency recognition international standard and so on read the card to the long-distance range and application program interface API makes had explicitly stipulated.