Zih Corporation

Supersensor (Proprietary) Limited

Btg International Limited

John McMurray

Christopher Gordon Gervase Turner

The invention describes a selection and arbitration method for reading a population of RFID transponders (tags). The transponders are selected or de-selected individually, or in one or more groups, using one or more command signals from a reader. The command signals from the reader include selection or de-selection criteria for selecting or de-selecting transponders by moving them between different states by setting or resetting a command flag, such as a flip-flop, in the transponders. The different transitional states include a Ready state, an Active state, a Standby state, a Singulated state and a Quiet state.

RFID group selection method

The invention describes an arbitration management method and system for use in identifying RFID transponders or tags which each transmit a response signal to a reader within a respective waiting period the maximum duration of which can be adjusted. The maximum duration is determined by a random number transmitted to a counter along a number of data lines, at least one of the data lines being provided with logic gates which block or permit data line signals reaching the binary inputs of the counter to control the maximum length of the waiting period.

Method and system for controlling RFID transponder response waiting periods

A method is described of calculating and verifying the integrity of data in a data communication system. The system comprises a base station and one or more remote stations, such as in an RFID system. The method includes transmitting a select instruction from the base station to the one or more remote stations, the select instruction containing a data field which matches a portion of an identity or other data field in one or more of the remote stations; transmitting from a selected remote station or stations a truncated reply containing identity data or other data of the remote station but omitting the portion transmitted by the base station; calculating in the base station a check sum or CRC from the data field originally sent and the truncated reply data received and comparing the calculated check sum or CRC with the check sum or CRC sent by the remote station.

Method and system for calculating and verifying the integrity of data in a data transmission system

A method of reading a plurality of transponderston forming part of an electronic radio frequency identification systemcomprises the steps of prompting the transponders atto transmit preamblesonly of respective response digital sequences to a reader. The reader then locks onto the preambletransmitted by one of the transponders and immediately causes a mute signalto be broadcast to mute all of the transponders not yet transmitting. The reader then transmits during a first time windowa first commandto cause the one transponder to transmit a remainder of the sequence. Having received and read the remainder, the reader transmits a second commandduring a second time windowto cause the one transponder to switch to a sleep mode wherein the one transponder no longer transmits any part of the sequence, and to unmute the muted transponders.

Reading protocol for transponders of electronic identification system

A method of reading a plurality of transpondersto.n forming part of an electronic radio frequency identification systemcomprises the steps of prompting the transponders atto transmit preamblesonly of respective response digital sequences to a reader. The reader then locks onto the preambletransmitted by one of the transponders and immediately causes a mute signalto be broadcast to mute all of the transponders not yet transmitting. The reader then transmits during a first time windowa first commandto cause the one transponder to transmit a remainder of the sequence. Having received and read the remainder, the reader transmits a second commandduring a second time windowto cause the one transponder to switch to a sleep mode wherein the one transponder no longer transmits any part of the sequence, and to unmute the muted transponders.

A transponderfor a radio frequency (RF) identification system comprises an antennahaving an antenna impedance (Z) having a real part (R) connected to transponder circuitry presenting a load impedance (Z) having a real part (R), a ratioof the real part (R) of the load impedance and the real part (R) of the antenna impedance having a first value that is bigger than one when the transponder is not transmitting data. During transmission of data the ratio is switched between the first value and a second smaller value.

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Gauteng, South Africa

John McMurray