Method and system for identifying and communicating with a plurality of contactless IC cards
First Claim
1. A contactless IC card communication system including:
- contactless IC cards; and
a read/write device communicating with the IC cards by means of electromagnetic waves, the read/write device comprising;
ID code acquisition means for requesting a response block from each of the contactless IC cards and for determining a time at which each of the contactless IC cards returns a response block containing an ID code, based on timing conditions directed to the contactless IC cards from the read/write device and an ID code of each of the contactless IC cards;
data communication means for identifying contactless IC cards for communication based on the ID codes and causing respective commands to be executed in the contactless IC cards identified;
means for receiving a response block containing an ID code from each of the contactless IC cards and detecting a data collision between response blocks;
means for changing the timing conditions in response to a data collision; and
means for re-requesting a response block from each of the contactless IC cards using the changed timing conditions.
1 Assignment
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Accused Products
Abstract
Even when a plurality of cards have entered an communication area, the cards within the communication area may be accessible, and, if a data collision occurs, the order of accessing to the cards is expeditiously determined to perform an efficient communication. Each card determines a timing for returning a response block containing an ID code based on conditions directed by a read/write device and the ID code of its own. The read/write device is caused to receive the response block returned by the contactless IC card and to detect a data collision. Based on this result, the conditions are changed so that a respective response block containing an ID code is returned again, thereby concurrently processing the plurality of contactless IC cards.
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Citations
6 Claims
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1. A contactless IC card communication system including:
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contactless IC cards; and a read/write device communicating with the IC cards by means of electromagnetic waves, the read/write device comprising; ID code acquisition means for requesting a response block from each of the contactless IC cards and for determining a time at which each of the contactless IC cards returns a response block containing an ID code, based on timing conditions directed to the contactless IC cards from the read/write device and an ID code of each of the contactless IC cards; data communication means for identifying contactless IC cards for communication based on the ID codes and causing respective commands to be executed in the contactless IC cards identified; means for receiving a response block containing an ID code from each of the contactless IC cards and detecting a data collision between response blocks; means for changing the timing conditions in response to a data collision; and means for re-requesting a response block from each of the contactless IC cards using the changed timing conditions. - View Dependent Claims (2, 3)
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4. A communication method for a contactless IC card system, the system including contactless IC cards and a read/write device, for communicating by means of electromagnetic waves, the communication method comprising:
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acquiring an ID code from each of the contactless IC cards by requesting a response block from each of the contactless IC cards utilizing a read/write device and determining a time for each of the contactless IC cards to send a response block based on timing conditions directed to the contactless IC cards from the read/write device and the ID code of each of the contactless IC cards; receiving a response block from each of the contactless IC cards and detecting whether a data collision of response blocks has occurred; changing the timing conditions in response to a data collision; re-requesting a response block from each of the contactless IC cards using the changed timing conditions; and communicating data to identified contactless IC cards based on the ID codes thereby causing the identified contactless IC cards to execute commands. - View Dependent Claims (5, 6)
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Specification