CA2033868C - System for reading and writing data from and into remote tags - Google Patents

System for reading and writing data from and into remote tags Download PDF

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Publication number
CA2033868C
CA2033868C CA002033868A CA2033868A CA2033868C CA 2033868 C CA2033868 C CA 2033868C CA 002033868 A CA002033868 A CA 002033868A CA 2033868 A CA2033868 A CA 2033868A CA 2033868 C CA2033868 C CA 2033868C
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Prior art keywords
data
tag
signal
interrogator
remote object
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CA002033868A
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French (fr)
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CA2033868A1 (en
Inventor
Jeremy A. Landt
Alfred R. Koelle
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Amtech Systems Inc
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Amtech Corp
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Classifications

    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07BTICKET-ISSUING APPARATUS; FARE-REGISTERING APPARATUS; FRANKING APPARATUS
    • G07B15/00Arrangements or apparatus for collecting fares, tolls or entrance fees at one or more control points
    • G07B15/06Arrangements for road pricing or congestion charging of vehicles or vehicle users, e.g. automatic toll systems
    • G07B15/063Arrangements for road pricing or congestion charging of vehicles or vehicle users, e.g. automatic toll systems using wireless information transmission between the vehicle and a fixed station
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B61RAILWAYS
    • B61LGUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L25/00Recording or indicating positions or identities of vehicles or vehicle trains or setting of track apparatus
    • B61L25/02Indicating or recording positions or identities of vehicles or vehicle trains
    • B61L25/04Indicating or recording train identities
    • B61L25/048Indicating or recording train identities using programmable tags
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06KGRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/0008General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
    • GPHYSICS
    • G08SIGNALLING
    • G08GTRAFFIC CONTROL SYSTEMS
    • G08G1/00Traffic control systems for road vehicles
    • G08G1/01Detecting movement of traffic to be counted or controlled
    • G08G1/017Detecting movement of traffic to be counted or controlled identifying vehicles

Abstract

The subject invention relates to a system for identifying, for writing data into and reading data out of electronic tags which may be attached to moving and moveable objects. An interrogator sends an RF signal to a remote tag, the signal including data intended to be received and stored in the tag.
The tag backscatter-modulates the received signal with data temporarily and permanently stored in the tag, including data indicating the identity of the object to which the tag is attached. The interrogator has the capability of (1) recognizing the identity of the tagged abject from the returned backscatter-modulated signal and (2) transmitting data to the tag only if it has data to be transmitted to that particular tagged object.
This permits data to be selectively transmitted to a tag and received and stored by that tag only after the tag has been identified as a correct one to receive that data. The tag, in addition, may have the capability of increasing its sensitivity to the receipt of transmitted data after receiving a signal from the interrogator of sufficient strength to be capable of transmitting data to that tag.

Description

. ~ ~~33~6~
03823.920 SYSTEM FOR READING AND WRITING
DATA FROM AND INTO REMOTE TAGS
BACKGROUND OF THE INVENTION AND PRIOR ART
The subject invention relates to a system for reading data from remote tags and for writing data into those tags.
There are a number of prior art object and vehicle identification systems which use electronic tags containing fixed data about the particular obiect. These electronic tags were originally devel-oped by the United States National Laboratory at Los Alamos, New Mexico, for the Department of Agriculture to identify livestock animals. A tag containing the animal's identification data in coded, electronically readable form, is attached to or implanted in the animal. Electronic readers are placed at feeding stations to read the tags as the animals passed nearby. These readers, also called interrogators, transmit an RF signal which, in turn, is "backscatter-modulated" with the identification data from the tag. These tags have an antenna which transmits the backscatter-modulated signal, containing the information from the tag, to the interrogator. These early systems are described in U.S. Patent Nos. 4,075,632 and 4,360,810.
As the technology progressed, it was found that these systems for identifying remote moving objects had utility far beyond animal identification. For example, the tags may be placed in any moving or moveable objects, such as automobiles, shipping containers or railroad cars. The information in these ,. , ~~~38~~
tags can be used to keep track of the location, identity and con-tents of these objects. One important use of these systems is for automated toll collection on a tollway. Automobiles passing through a toll lane need not stop to deposit cash. The elec-tronic interrogator alongside of the toll lane electronically identifies the moving car as it passes by, and triggers a com-puterized debiting system so that the car owner's credit card may automatically be debited for the amount of the toll. Similarly, shipping containers or railroad rolling stock can be continually monitored at ports, loading docks or along the tracks so that their location, identity and contents can be continually moni-tored on a central computer. U.S. Patent Nos. 4,739,328;
4,782,345; 4,786,907; 4,816,839; 4,835,377 and 4,853,705 all describe aspects of these systems, including antennas and pro-grammers used in these systems to identify remote objects.
In certain applications, it has became important not only to read the data contained in these electronic tags attached to the moving objects, but also to modify that data, or to "write" data into the tags while they are in motion. For ex-ample, it may be important not only to know the contents of a railroad car but also the route and time it took to reach a par-ticular destination. Such route data, or data from which infor-mation may be calculated by a computer, may be written into the tag as it passes interrogators along its route. U.S. Patent No.
4,390,880 describes one technique for both writing data into and reading data out of such a tag. In this patent, the interrogator
-2-at the remote receiving station first transmits to the tag, prior to being able to identify the tagged object and prior to trans-mitting any information-bearing signals to the tag, an "inter-rogation command signal". This signal tells the tag to transmit the identification data stored in the tag's memory to the trans-mitter. After the interrogator recognizes this identification data, it sends a "key signal" to the tag to enable a WRITE oper-ation. The tag first must receive and recognize this key signal transmitted from the interrogator before the WRITE may take place.
This sequence requires that, prior to the remote re-ceiving station (the interrogator) receiving any identification information back from the tag, that the tag first be "enabled" by the receipt and recognition of the transmitted interrogation sig-nal. The tag and the interrogator must therefore be in suffi-ciently close proximity so that the tag first can receive and understand this interrogation signal from the transmitter, recog-nize .it, and finally retransmit the data stored in its memory back to the interrogator. This need for the tag to be in close enough proximity to the interrogator to receive the enabling interrogation signal reduces the time window available for read-ing the contents of the tag and for writing data into the tag.
In some applications, such as reading and writing data from and into a fast-moving train, this "handshake" delay can be suffi-cient to miss the tag completely.
-3-...
i The system of this invention considerably lessen ~~
handshake delay by employing a tag which continually indicates its own identity, even in the absence of any interrogating command signal from the interrogator. No interrogation command signal is transmitted by the intzrrogator to enable reading of the tag. The tags of the subject invention use a continuously scrolling fixed code to transmit their identity. This same transmitted code also tells the interrogator whether or not the tag is in sufficiently close proximity so that the interrogator can confidently transmit arid write data to the tag. Since the maximum range at which the interrogator can read the backscatter-modulated, transmitted signal from the tag is considerably greater than the maximum write range allowable for the interroga-tor to write data into the tag, the ability of the interrogator to read all the necessary information from the tag in advance of the tag coming into write range saves critical time.
Accordingly, the technique used in this invention substantially speeds up reading and writing, greatly increasing the maximum operational range.
For example, a tag of this invention can be read as far as 80 feet away from an interrogator, but can only be written to at a maximum distance of about 20 feet. To the contrary, the tags described in U.S. Patent No. 4,390,880 aan only be read at about 6 feet and written into at about 4 feet. In the system of the subject invention, a tag may first be read and identified as it approaches a distance of about 80 feet from the interrogator.
_4-~~~~~68 It may be written to at about 20 feet, saving the critical time that the tag is within the 20 feet write range of the interroga-tor exclusively for the more range-limited write operation.
BRIEF DESCRIPTION OF THE INVENTION
Briefly, the system of this invention for identifying and for writing data into remote objects, which may be in motion relative to the interrogator, employs an interrogator for sending an RF signal to the remote object. This signal includes data intended to be received and stored by the remote object. The remote objects are capable, upon receipt of the transmitted RF
signal, of backscatter-modulating that RF signal and returning a signal which is backscatter-modulated with data indicating the identity of the remote object. The interrogator has the capa-bility of (1) recognizing the identity of the remote object from the returned, backscatter-modulated signal and (2) transmitting data to the remote object only if the interrogator has data to be transmitted to that particular, identified remote object. In this manner, data may be selectively transmitted to and received and stored by a remote object only after the remote object has been identified as the correct remote object for the receipt of such data.
The remote object is continuously powered for back-scatter-modulating received RF signals even when no actual RF
signal is being received. This is different from the tags of the prior art which transmit the identification information only when r.
triggered by an interrogation signal from the transmitter. In a preferred embodiment of the invention, the write sensitivity of the tag is automatically increased when the tag senses that an RF
field from an interrogator is sufficiently strong to write data into ttie tag .
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood by reference to the following drawings in which:
Fig. 1 illustrates the interrogator-tag signalling se-quence of the invention;
Fig. 2 shows the RF WRITE code used for the pulses of the invention;
Fig. 3 is a block diagram, partially in schematic, of the circuitry of the read/write tag of the invention; and, Fig. 4 is a state diagram of a tag of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Unlike the tags of the prior art, the tag of the inven-tion continuously scrolls through the data in its memory. In a preferred embodiment, this data is contained in two 128-bit code frames. The first code frame holds permanent data; the second holds temporary, or overwriteable data. This type of tag is called a "read/write" tag. Both permanent and temporary data are continuously scrolled by the tag and thus always available to be read by an interrogator of the invention. The details of these tags and interrogators are not described herein except the aspects providing the novel features of this invEntion because they have been previously described in one or more of U.S. Patent Nos. 4,739,328; 4,782,345; 4,786,907; 4,816,839; 4,835,377 and
4,853,705. The data encoding used to read these tags is the same as described in U.S. Patent 4,739,328.
As soon as the tag comes within range of the transmit-ted RF signal from an interrogator, the tag will backscatter-modulate the signal from the interrogator, in sequence, with the two 128-bit code frames. These will then be received and inter-preted by the interrogator, as shown in step 10 of Fig. 1. As-suming the tag is a proper one, the interrogator caill recognize the tag's ID signal as valid. It will also capture all the data from the tag, which may include its identity as well as other information about the container or the vehicle to which it is attached, such as its weight, contents, size and the like. More-over, from certain encoding of one or both of the 128-bit code frames, the interrogator will recognize that the tag is a read/write tag (as opposed to a read-only tag). Any single bit or pair of bits of either of the two 128-bit code frames, for example, may be used to identify that the tag is read/write.
This identification step is shown as step 11 in Fig. 1.
As the tag approaches closer to the interrogator (or the interrogator approaches closer to the tag in some applica-tions where the interrogator is moving and the tag is fixed), the tag continually monitors the stxength of the RF field from the interrogator. As soon as the tag senses that the transmitted RF
field is sufficiently strong to enable data to be securely writ-ten into the tag, the tag will change the code in one or more code frames which it is backscatter-modulating onto the transmit-ted RF signal, to so indicate.
For example, if two bits of. one of the tag's code frames are used to identify that the tag is a read/write tag, the order of these two bits may be reversed when the tag senses that the RF signal is sufficiently strong. The so modified back-scatter-modulated signal then is returned to the interrogator, indicating that there is sufficient transmission strength for a write operation. This is shown in step 12 of Fig. 1. At the same time, the tag increases its own reception sensitivity, also as indicated in step 12, in a manner which will be described later. All three of these steps go on at once, as shown in step 12 of Fig. 1.
The re-coded backscatter-modulated recognition signal from the tag alerts the interrogator that there is a candidate read/write tag in its RF range, that the sensitivity of the tag has been increased and that it may write data into this tag if it so desires. In step 13 of Fig. 1, the interrogator recognizes that: (1) there is a read/write tag in its range; and (2) the sensitivity of that tag has been increased so that it is ready to receive a WRITE of any data from the interrogator which is to be written into the tag's memory. As indicated in step 14, the interrogator then checks to see if it has a message for that tag, _g_ .r ~~~~
having already received and read the tag's identification. The interrogator compares the received tag identification with its message list to see whether it has a message for that tag. If it does, it then sends the message to the tag on the RF carrier, as shown in step 15 of Fig. 1.
After receipt and storage of the message from the interrogator, the tag echoes its newly received data on a backscatter-modulated signal sent back to the interrogator, as illustrated in step 16. The interrogator, in turn, checks the new data which it gets back from the tag against the message it sent out on the transmitted RF signal, as shown in step 17 in Fig. 1. If there is agreement, the WRITE operation is succes-sfully completed, and thus terminated, as shown in step 18. If there is an error, the interrogator will retransmit the message, as shown in step 19, as long as the tag is still in range to receive the message. This process is repeated until a successful transmission occurs, or the tag indicates by its scrolling mes-sage (or absence of any message) that it is out of range for any more WRITE operations.
The signalling sequence shown in Fig. 1 has significant advantages. Typically, a tag enters the range at which it may be read by the interrogator a significant period of time before it gets close enough for the interrogator reliably to write data into the tag. This difference arises because of the difference between the natures of read and write procedures. The system of this invention takes advantage of this range requirement differ-_g_ ential by completing the initial tag read and recognition process prior to the tag entering into the write zone where it may be written into. This allows significantly more write transaction time because none of the time while the tag is in the write zone need be taken up by the recognition sequence, which already has been completed. The fact that the tag of the invention is con-tinuously scrolling its identification data makes possible virtu-ally instant recognition by the interrogator.
Furthermore, the sequence of operation shown in Fig. 1 ensures that the interrogator does not waste time trying to write data into a tag that is not within its range. The interrogator will not attempt to write into a tag until it receives the back-scatter-modulated range and sensitivity verification shown in step 13 of Fig. 1. However, as soon as that verification is re-ceived by the interrogator, indicating the tag remains within range, the entire time that the tag is within the write range can be used for the writing sequence.
The signalling sequence of the invention has consider-able advantages over the prior art sequence which requires the interrogator first to "wake up'' the tag before the interrogator can identify it. With the prior art systems the tag had to be in the "write zone" before it can be identified. The "wake up"
command is similar to a write command and thus requires that the tag be in the much shorter "write range" in order to be woken up.
Since the tag of the subject invention is always scrolling, it can be identified by the interrogator while it is in the longer read range, thereby substantially speeding up tag-interrogator communications.
In a preferred embodiment, the tags and readers of the read/write system of this invention are compatible with the tags and readers of the read-only system described in the above-identified earlier patents. For example, if a read-only tag enters the RF field of a read/write interrogator, the data on the read-only tag will be read and the tag identified as a read-only tag. The reader and host computer can then use uhis data as desired. Conversely, if a read/write tag of this invention enters the RF field of a read-only interrogator of the earlier patents, the data in the tag will be read, and the reader and host computer can use this data as desired.
In order to accomplish the signalling sequence shown in Fig. 1, the interrogator and tag need use only three different signals for writing data into the tag. The first signal, shown in Fig. 2, represents a binary "ZERO" by turning the RF off for a period of 25 microseconds. The second signal, which turns the RF
off for a period of 75 microseconds, represents a binary one.
The third signal, Which turns the RF off for 125 microseconds, indicates a '°COMMAND 1" signal, the use of which will be described below. Using the signalling technique shown in Fig. 1 and the state diagram shown in Fig. 4, the entire WRITE operation between the interrogator and the tag may be carried out using only these three signals shown in Fig. 2.

The circuitry of a preferred embodiment of the tag of this invention is shown in Fig. 3. The tag has an antenna 30, which was described in U.S. Patent Nos. 4,782,345 and 4,816,839.
Antenna 30 is connected to an RF .rectifier 31 connected to con-trollable load resistance 32, as shown. Load resistance 32 modu-lates the load on the RF rectifier which, in turn, modulates the backscatter to send the coded signals back from the tag to the interrogator. This system is described in more detail in U.S.
Patent No. 4,075,632.
Unlike the systems described in the above patent, as soon as level detector 35 detects that the RF signal reaching antenna 30 is above a predetermined thi:eshold level, it sends a signal through write signal decoder 36 to control logic 34.
Control logic 34 at the same time changes thE~ data in the tag message memory, for example, by reversing two bits of informa-tion. This changed data comes out on line 37 as the "read back message" of the signal which passes to controllable load resis-tance 32. Controllable load resistance 32 modulates the back-~scatter by changing the load on RF rectifier 31, which in turn changes the RF load on antenna 30. The tag thus sends a back-scatter-modulated signal having a two-bit code change back to the interrogator, indicating to the interrogator (1) that the tag is within the write range, and (2) that the tag's threshold sensi-tivity has been increased, as will be explained below.
When the tag comes within close enough proximity to the interrogator so the RF field is of sufficient strength for infor-~~~~'r(~~G
mation to be written into the tag, the tag's sensitivity is in-creased. When level detector 35 senses the presence of suffi-cient Rb'' strength for a WRITE operation, a SENSITIVITY CONTROL
SIGNAL is emitted from control logic 34 onto line 38 and across resistor 39 which decreases the threshold voltage across recti-fier 31 from 0.6 volts to 0.3 volts. The resultant sensitivity level of the tag is governed by the ratio of the resistances of resistor 39 to resistor 33, along with the voltage of the sensi-tivity control signal on line 38.
Once the sensitivity of the tag is thus increased and the readback message signal (with the two reversed bits) is backscatter-modulated and returned to the interrogator, the interrogator may, if it desires to write information into that particular tag, then send an RF WRITE signal. The WRITE signal appears on antenna 30, passes through rectifier 31, resistor 40, from the base to the collector of bipolar transistor 41 and on through level detector 35 to the WRITE signal decoder 36. WRITE
signal decoder 36 separates the signal voltage-time pattern into the codes for a COI~~tAND 1, a binary 1 or a binary 0. These are the three possible signals shown in Fig. 2.
If the RF signal is a WRITE signal, the WRITE signal decoder 36 recognizes the WRITE signal by the presence of a COI~ND 1 signal. Once recognized as a WRITE signal, the WRITE
signal is allowed to pass through control logic 34 to the tag message memory 42 where the frames of data to be written into the tag will be stored. This message memory may be any non-volatile ~61~'~Sr'~'~) :l t f.'~' l:' ~ V
memory, such as EEPROM, EAROM or battery-backed RAM. During an actual WRITE operation, level detector 35 makes sure the signal remains of sufficient RF strength and the WRITE signal decoder 36 recognizes the signal as a WRI~PE signal and the control logic 34 allows the tag memory 42 to store the data. Then the control logic 34 pulls the newly written data from the tag memory 42 and puts it out onto readback message line 37 for transmission to and verification by the interrogator.
Resistors 33 and 40 and capacitor 43 adjust the thresh-old level of the tag for detecting received RF pulses. This level is preferably maintained at about the raid-point of the normal received pulse height. Resistors 33 and 40 set this level, and capacitor 43 holds it in place during the intervals between pulses. Resistor 39, together. with the output voltage on line 38 from control logic 34, determine hocv much the tag sensi-tivity will be increased after the tag has received an RF signal from the interrogator of sufficient strength for the interrogator to write information into it. Resistor 44 .is a normal load resistor. In a preferred embodiment of the invention, resistor 40 is 10 Kohms, resistor 33 is 30 Kohms, resistor 39 is 270 Kohms, resistor 44 is also 270 Kohms and capacitor 43 is .022 microfarads.
The tag state diagram of Fig. 4 illustrates the signal-ling sequence used for reading information from the tag and writ-ing information to the tag. When the tag is not in the RF range of the interrogator, it remains in the READ 1 mode 20. While in _14-a ~~~~~~~6~
this mode, the tag is continually scrolling so that it is always ready to backscatter-modulate any received RF signal with the data in its message memory. As soon as the tag enters into an RF
field from an interrogator, when the field is above a predeter-mined strength, the tag senses that strength and switches into the READ 2 mode 21 in Fig. 4. This is done as described above.
In the READ 2 mode, the tag has increased sensitivity and the tag still backscatter-modulates the received RF signal with the data in its tag memory. Assuming the tag is a read/write tag, it will reverse the two bits to indicate its readiness to be written to.
The interrogator, receiving all this identity informa-tion as well as the two reversed bits, knows the ID of the tag, that it is a read/write tag and that it is in range and ready to be written into. Where the interrogator has data to be written into that tag, the interrogator will then send the data frame to be written. The interrogator first sends a COMMAND 1 pulse which tells the tag it intends to write data. The tag then, recogniz-ing the COMMAND 1 pulse, causes the scrolling to stop. This is accomplished by the write signal decoder 36 sending a signal to the control logic 34 (shown in Fig. 3), which in turn disconnects its output line 37. The tag is now in the WRITE mode 22 shown in Fig. 4. Next the interrogator sends the first 120 bits of fixed data to the tag. The control logic 34 compares this fixed data, bit by bit, with the data in the tag memory 42. If they agree, the tag memory 42 is unlocked by control logic 34 so it may be ~~~s written into through line 46. This verification procedure pre-vents a tag being overwritten with the wrong data.
After the tag has received and compared the 120-bit identification message, the interrogator sends an additional eight bit command word to the tag. CO~IAND words are sent to the tag by the interrogator while the tag is in the WRITE mode 22.
These frames set up the tag in the mode to do various operations, including scrolling through the contents of its memory, or re-ceiving a WRITE command from the interrogator.
In operation, a command word tells the tag what to do with the next 128 bits it will receive. In the present embodiment, there are four possibilities: (1) to write the data into a volatile data field; (2) to write the data into a fixed data field; (3) to unlock a fixed data field to allow data to be written into it; or (4) to lock a fixed data field so that no data may be written into it. When the tag then receives the next one hundred twenty-eight bits of data, it will act i.n accordance with the command word. The tag recognizes the code which indicates the end of data to be written and switches itself back to the READ 2 mode shown in Fig. 4. This completes the WRITE
operation. The described embodiment is limited to 256 bits of data, and a limited command set. The invention, however, permits the use of additional data frames and control of the reading and writing of specific frames, limited only by memory capacity and the time the tag is within the RF field of the reader.

~' (.e After returning to the READ 1 mode, line 37 will be reconnected and the tag will continue scro113.ng, sending back all its fixed and its newly written data to the interrogator. This, of course, can occur either before or after the tag has left the increased sensitivity WRITE range. As was discussed earlier, tags may still be read even after they no longer can be written into. Accordingly, by reading the newly scrolling data, the interrogator can verify that its WRITE message was properly received, decoded and stored in the tag's memory. Furthermore, if the tag has not yet left the WRITE range, and the interrogator happens to detect an error in the new message, the interrogator can retransmit the same message and re-attempt to place the cor-rect data into the tag's memory.
Where the tag is in the WRITE mode 22, and the RF field stops for some reason so that the tag is no longer receiving an RF signal from the interrogator, level detector 35 (Fig. 3) sends a signal to control logic 34 to cause the tag to revert to the READ 1 mode 20 shown in Fig. 4.
The advantage of the variable threshold sensitivity feature provided by the circuit of the preferred embodiment shown in Fig. 3 is that in the READ 1 mode, where there is no traps- , mitted RF signal, the circuit draws almost no background current.
During those periods, the detection level sensitivity is about 0.6 volts, which ie the normal emitter-base threshold voltage of silicon bipolar transistor 41. Accordingly, during these quies-cent periods, that transistor 41 is OFF and draws almost no cur-~~u~C~
rent. However, in the presence of an RF signal which exceeds the predetermined threshold level, as discussed above, the tag is switched into its more sensitive, active mode, the voltage across resistor 33 goes up from 0 volts to 0.3 volts and the signal threshold voltage drops by the same amount to 0.3 volts. In this active "WRITE" mode, operating current is drawn, but only during the period when a WRITE signal is being transmitted from the interrogator. As soon as the WRITE procedure has been completed and the new data stored, the tag automatically reverts to the lower sensitivity READ 1 mode because level detector 35 will detect the reduced RF signal for a period of time longer than is normal for any transmitted pulse chain. Since the increased operating current is on only for short periods of time during a WRITE operation, there is very little penalty in tag battery life.
This increase in tag sensitivity during a WRITE opera-tion is important because it ensures, as a tag approaches the interrogator, that the signals will be properly received. RF
levels do not always increase smoothly as a vehicle or train bearing a tag approaches an interrogator. There are often local dips in RF signal levels due to standing waves, shadowing or other reasons. By increasing tag sensitivity during the WRITE
cycle, the probability of continuing to have sufficient RF to provide a secure, uninterrupted write operation is increased.
The system of the invention preferably uses a single common RF carrier and RF signal poJ.arization for both the READ

and the WRITE signals. The system uses a common antenna 30, shown in Fig. 4, as well as a common rectifier circuit 31 for both the reception of WRITE data from the interrogator and for modulating a load onto the same rectifier circuit 31 for sending backscatter-modulated signals back to the interrogator. during the READ operation. It would be possible, if desired, and may in some cases be preferable to use two antennas on the tag, one for receiving data and one for sending. However, a single antenna allows for a smaller tag.
Time division multiplexing is used to separate the reader-to-tag communications from the tag-to-interrogator com-munications. Often, several or many interrogators must operate simultaneously in close proximity with one another. An example of such an installation is at a toll plaza on a toll road, tun-nel, or bridge, where every lane may have an interrogator. In such installations, interrogators axe synchronized so that the modulated signals produced by interrogators do not interfere with other interrogators reading data from other tags. Interference between interrogators while tags are being read is eliminated by using different frequencies so that each interrogator operates on a unique frequency. Data received by the tag is determined to be valid in accordance with a threshold voltage value, which may be adjusted using resistors 33 and 40 and capacitor 43, together with sensitivity control signal 38. This threshold is preferably maintained at about the mid-point of the normal received pulse height. This self-compensation feature reduces corruption of y k~ ,Y ~ C: :.~
data due to other extraneous sources of RF energy, such as un-related sources at frequencies close to the interrogatory fre-quency, such as cellular phones, and signals produced by other nearby interrogators.
Reader synchronization may be done by wire or prefer-ably using a self-synchronizing feature of the invention. If one interrogator is attempting to write to a tag, the modulation of the signal sent by that interrogator may cause interference with an adjacent interrogator. An integral part of the write cycle is to first read all data from the tag. During this reading time period, an adjacent interrogator can also read a tag if one is present, and consequently becomes synchronized automatically to the first interrogator. After both interrogators have acquired two frames of data from their respective tags, then both are ready to write and thus are in synchronization with each other.
As will be apparent to those skilled in the art, many modifications can be made to the preferred embodiment of the invention shown in Figs. 1-4 and described above. Accordingly, the invention is only limited as set forth in the claims which follow.

Claims (11)

1. A system for identifying, for writing data into, and reading data out of remote objects which may be in motion relative to the interrogator, comprising:
an interrogator for sending an RF signal to said remote object, said signal including data intended to be received and stored by said remote object;
at least one remote object capable, upon receipt of said RF signal, of backscatter-modulating said RF signal and returning a backscatter-modulated signal to said interrogator, said backscatter-modulated signal being modulated with data indicating the identity and other data stored in said remote object;
said interrogator having the capability (1) to recognize the said identity and other data stored in said remote object from said returned backscatter-modulated signal and (2) to transmit data to said remote object only if said interrogator has data to be transmitted t.o that identified remote object, whereby data may be selectively transmitted to and received and stored by a remote object only after such remote object has been identified as the correct remote object to receive such data.
2. The system for identifying, for writing data into, and reading data out of remote objects of claim 1 further characterized by said remote object being continuously capable of backscatter-modulating received RF signals with its stored data at all times.
3. The system for identifying, for writing data into and reading data out of remote objects of claim 1 further characterized by said remote object having the further capability of increasing its sensitivity to received RF signals containing data to be written into said remote object after receipt and recognition of an RF signal of adequate strength for data to accurately be written into said remote object.
4. A system for identifying, for writing data into and for reading data out of remote objects which may be in motion relative to the interrogator, comprising:
an interrogator for sending an RF signal to said remote object, said signal including data intended to be received and stored by said remote object;
at least one remote object capable, upon receipt of said RF signal, of backscatter-modulating said RF signal and returning a backscatter-modulated signal to said interrogator, said backscatter-modulated signal being modulated with data indicating (1) the identity and other data stored in said remote object and (2) its ability or inability to receive and store transmitted data from said interrogator; and said interrogator having the capability (1) to recognize the said identity and other data stored in said remote object from said returned backscatter-modulated signal and (2) to transmit data to said remote object only if (i) said interrogator has data to be transmitted to that identified remote object, and (ii) said backscatter-modulated returned signal indicates the ability of said remote object to receive and store transmitted data, whereby data may be selectively transmitted to and received and stored by a remote object having data storage capability only after such remote object has been identified as the correct remote object to receive such data.
5. The system for identifying, for writing data into and reading data out of remote objects of claim 4 further characterized by said remote object indicating to said interrogator its ability to receive and store transmitted data by the existence of writable semiconductor memory within said object.
6. The system for identifying, for writing data into and reading data out remote objects of claim 4 further characterized by said remote object determining its ability to receive and store transmitted data by sensing the strength of the received RF
signal and determining whether or not it is adequate for data accurately to be written into said remote object, and indicating this ability to said interrogator.
?. A tag adapted to be attached to a remote object, said tag containing data identifying said remote object arid other stored data and being capable of having at least a portion of its data contents varied by the receipt of an RF signal from a transmitter which may be in motion relative to said tag, comprising:
a writable memory;
a backscatter-modulating means which, upon receipt of said RF signal, backscatter-modulates said RF signal and returns a backscatter-modulated signal to said transmitter, said back-scatter-modulated returned signal being modulated with data including the identity of said remote object, said remote object being continuously capable of backscatter-modulating received RF
signals at all times.
8. The tag of claim 7 further characterized by being capable of indicating to said interrogator its ability to receive and store data by a modification within the tag of a portion of data contained in the writable semiconductor memory.
9. The tag of claim 7 further characterized by being capable of determining its ability to receive and store transmitted data by sensing the strength of the received RF signal and determining whether or not it is adequate for data accurately to be written into said tag.
10. The tag of claim 9 further characterized by having the capability, upon receipt of said RF signal, of backscatter-modulating said RF signal and returning a signal modulated with data indicating (1) the identity and other data stored in said remote object and (2) whether or not the received RF signal is of sufficient strength so that the tag is able to receive and store transmitted data from said interrogator.
11. The tag of claim 7 further characterized by having the capability of increasing its sensitivity to received RF
signals containing data to be written into said tag after receipt and recognition of an RF signal of adequate strength for data accurately to be written into said tag.
CA002033868A 1990-01-16 1991-01-09 System for reading and writing data from and into remote tags Expired - Lifetime CA2033868C (en)

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Families Citing this family (188)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE500030C2 (en) * 1990-05-14 1994-03-21 Bengt Henoch Procedure for storing complicated product life data
DE4107311C2 (en) * 1991-03-07 1996-02-08 Telefunken Microelectron Method for the wireless transmission of data on a data carrier
US5340968A (en) * 1991-05-07 1994-08-23 Nippondenso Company, Ltd. Information storage medium with electronic and visual areas
JP2993186B2 (en) * 1991-06-28 1999-12-20 株式会社デンソー Aircraft baggage management system
SE9201864D0 (en) * 1992-06-17 1992-06-17 Saab Scania Combitech Ab SYSTEM FOR INFORMATION TRANSFER WITH MULTIPLE TRANSPONDERS
US6144916A (en) * 1992-05-15 2000-11-07 Micron Communications, Inc. Itinerary monitoring system for storing a plurality of itinerary data points
US5787174A (en) * 1992-06-17 1998-07-28 Micron Technology, Inc. Remote identification of integrated circuit
WO1994000921A1 (en) * 1992-06-25 1994-01-06 Nippondenso Co., Ltd. Mobile object identification device
US5613228A (en) * 1992-07-06 1997-03-18 Micron Technology, Inc. Gain adjustment method in two-way communication systems
US7158031B2 (en) 1992-08-12 2007-01-02 Micron Technology, Inc. Thin, flexible, RFID label and system for use
DE4227551A1 (en) * 1992-08-20 1994-02-24 Eurosil Electronic Gmbh Chip card with field strength detector
DE69323460T2 (en) * 1992-09-07 1999-07-08 Denso Corp Communication system
US5434396A (en) * 1992-11-10 1995-07-18 Xicor Inc. Wireless powering and communication system for communicating data between a host system and a stand-alone device
US5450088A (en) * 1992-11-25 1995-09-12 Texas Instruments Deutschland Gmbh Transponder arrangement
US20050040961A1 (en) * 1995-04-11 2005-02-24 Tuttle John R. RF identification system with restricted range
US6097301A (en) * 1996-04-04 2000-08-01 Micron Communications, Inc. RF identification system with restricted range
US5491482A (en) * 1992-12-29 1996-02-13 David Sarnoff Research Center, Inc. Electronic system and method for remote identification of coded articles and the like
EP0625714A1 (en) * 1993-05-19 1994-11-23 Texas Instruments Deutschland Gmbh Method of transmitting a data message stored in a transponder device to an interrogating device
US5485520A (en) * 1993-10-07 1996-01-16 Amtech Corporation Automatic real-time highway toll collection from moving vehicles
US5430441A (en) * 1993-10-12 1995-07-04 Motorola, Inc. Transponding tag and method
US5414624A (en) * 1993-11-08 1995-05-09 Avid Systems Corporation Automated vehicle parking system
DE69516568T2 (en) * 1994-03-04 2001-01-04 Ncr Int Inc Extended wireless transmission system with modulated reflection
JPH07271939A (en) * 1994-03-30 1995-10-20 Mitsubishi Denki Semiconductor Software Kk Non-contact ic card, card reader/writer and card device
US6019394A (en) * 1994-04-28 2000-02-01 Ncr Corporation Multiple function interactive product label
US5731754A (en) * 1994-06-03 1998-03-24 Computer Methods Corporation Transponder and sensor apparatus for sensing and transmitting vehicle tire parameter data
DE4420462A1 (en) * 1994-06-13 1995-12-14 Sel Alcatel Ag Method for selecting one of at least two telecommunication terminals and telecommunication terminal therefor
US5469978A (en) * 1994-07-12 1995-11-28 Keystone Railway Equipment Company, Inc. Condition indicating system for railway car cushioning unit
DE4425271A1 (en) 1994-07-18 1996-01-25 Sel Alcatel Ag Method and device arrangement for secure, anonymous payment transactions
US5712630A (en) * 1994-07-26 1998-01-27 Matsushita Electric Works. Ltd. High power moving object identification system
GB9416349D0 (en) * 1994-08-12 1994-10-05 Neopost Ltd Mailing system
US7616094B2 (en) * 1994-09-09 2009-11-10 Intermec Ip Corp. Radio frequency identification system with write broadcast capability
US5606322A (en) * 1994-10-24 1997-02-25 Motorola, Inc. Divergent code generator and method
US5583507A (en) * 1995-04-19 1996-12-10 Martin Marietta Corporation Passive identification of friend vs. foe apparatus and method
US6329139B1 (en) 1995-04-25 2001-12-11 Discovery Partners International Automated sorting system for matrices with memory
US5874214A (en) * 1995-04-25 1999-02-23 Irori Remotely programmable matrices with memories
US6331273B1 (en) 1995-04-25 2001-12-18 Discovery Partners International Remotely programmable matrices with memories
US6416714B1 (en) 1995-04-25 2002-07-09 Discovery Partners International, Inc. Remotely programmable matrices with memories
US6017496A (en) 1995-06-07 2000-01-25 Irori Matrices with memories and uses thereof
US5751629A (en) * 1995-04-25 1998-05-12 Irori Remotely programmable matrices with memories
US5741462A (en) * 1995-04-25 1998-04-21 Irori Remotely programmable matrices with memories
US7002475B2 (en) * 1997-12-31 2006-02-21 Intermec Ip Corp. Combination radio frequency identification transponder (RFID tag) and magnetic electronic article surveillance (EAS) tag
US5936542A (en) * 1995-09-11 1999-08-10 Nomadix, Llc Convention ID badge system
US5591951A (en) * 1995-10-12 1997-01-07 The Regents Of The University Of California System and method for simultaneously collecting serial number information from numerous identity tags
US6032299A (en) * 1995-10-30 2000-03-07 Welsh; Nicole Jacket for reducing spinal and compression injuries associated with a fall from a moving vehicle
US5737710A (en) 1995-11-07 1998-04-07 Amtech Corporation Automated vehicle parking system for a plurality of remote parking facilities
US7640185B1 (en) 1995-12-29 2009-12-29 Dresser, Inc. Dispensing system and method with radio frequency customer identification
FR2743194B1 (en) * 1995-12-29 1998-03-20 Sgs Thomson Microelectronics POINTED CARD IDENTIFICATION FOR COMPUTER-AIDED MANUFACTURING
US6078251A (en) * 1996-03-27 2000-06-20 Intermec Ip Corporation Integrated multi-meter and wireless communication link
US7358857B1 (en) 1996-03-27 2008-04-15 Symbol Technologies, Inc. Global positioning systems applications
US5850187A (en) * 1996-03-27 1998-12-15 Amtech Corporation Integrated electronic tag reader and wireless communication link
US6097292A (en) * 1997-04-01 2000-08-01 Cubic Corporation Contactless proximity automated data collection system and method
US6194992B1 (en) 1997-04-24 2001-02-27 Nomadix, Llc Mobile web
US6696879B1 (en) 1996-05-13 2004-02-24 Micron Technology, Inc. Radio frequency data communications device
US6774685B2 (en) 1996-05-13 2004-08-10 Micron Technology, Inc. Radio frequency data communications device
US6836468B1 (en) 1996-05-13 2004-12-28 Micron Technology, Inc. Radio frequency data communications device
US6130602A (en) * 1996-05-13 2000-10-10 Micron Technology, Inc. Radio frequency data communications device
US6941124B1 (en) 1996-05-13 2005-09-06 Micron Technology, Inc. Method of speeding power-up of an amplifier, and amplifier
US5774876A (en) * 1996-06-26 1998-06-30 Par Government Systems Corporation Managing assets with active electronic tags
US6067297A (en) * 1996-06-28 2000-05-23 Symbol Technologies, Inc. Embedded access point supporting communication with mobile unit operating in power-saving mode
US5874902A (en) * 1996-07-29 1999-02-23 International Business Machines Corporation Radio frequency identification transponder with electronic circuit enabling/disabling capability
US6466131B1 (en) * 1996-07-30 2002-10-15 Micron Technology, Inc. Radio frequency data communications device with adjustable receiver sensitivity and method
US6107910A (en) * 1996-11-29 2000-08-22 X-Cyte, Inc. Dual mode transmitter/receiver and decoder for RF transponder tags
US5952922A (en) * 1996-12-31 1999-09-14 Lucent Technologies Inc. In-building modulated backscatter system
US6243012B1 (en) 1996-12-31 2001-06-05 Lucent Technologies Inc. Inexpensive modulated backscatter reflector
US6184841B1 (en) 1996-12-31 2001-02-06 Lucent Technologies Inc. Antenna array in an RFID system
US6456668B1 (en) 1996-12-31 2002-09-24 Lucent Technologies Inc. QPSK modulated backscatter system
US5784686A (en) * 1996-12-31 1998-07-21 Lucent Technologies Inc. IQ combiner technology in modulated backscatter system
US6046683A (en) * 1996-12-31 2000-04-04 Lucent Technologies Inc. Modulated backscatter location system
US6130623A (en) * 1996-12-31 2000-10-10 Lucent Technologies Inc. Encryption for modulated backscatter systems
US6208062B1 (en) 1997-08-18 2001-03-27 X-Cyte, Inc. Surface acoustic wave transponder configuration
US6060815A (en) 1997-08-18 2000-05-09 X-Cyte, Inc. Frequency mixing passive transponder
US6114971A (en) 1997-08-18 2000-09-05 X-Cyte, Inc. Frequency hopping spread spectrum passive acoustic wave identification device
US5986382A (en) 1997-08-18 1999-11-16 X-Cyte, Inc. Surface acoustic wave transponder configuration
US6339385B1 (en) 1997-08-20 2002-01-15 Micron Technology, Inc. Electronic communication devices, methods of forming electrical communication devices, and communication methods
US5974368A (en) * 1997-08-29 1999-10-26 Sarnoff Corporation Remote vehicle data interface tag system
US6064705A (en) * 1997-08-20 2000-05-16 Sarnoff Corporation Manchester encoding and decoding system
WO1999009719A1 (en) * 1997-08-20 1999-02-25 Sarnoff Corporation Remote vehicle data interface tag system
JP4008546B2 (en) * 1997-09-19 2007-11-14 株式会社東芝 Wireless information storage medium
US6061614A (en) * 1997-10-17 2000-05-09 Amtech Systems Corporation Electronic tag including RF modem for monitoring motor vehicle performance
US7844505B1 (en) 1997-11-21 2010-11-30 Symbol Technologies, Inc. Automated real-time distributed tag reader network
US7035818B1 (en) 1997-11-21 2006-04-25 Symbol Technologies, Inc. System and method for electronic inventory
US6329915B1 (en) * 1997-12-31 2001-12-11 Intermec Ip Corp RF Tag having high dielectric constant material
US6177872B1 (en) 1998-03-13 2001-01-23 Intermec Ip Corp. Distributed impedance matching circuit for high reflection coefficient load
US6281794B1 (en) 1998-01-02 2001-08-28 Intermec Ip Corp. Radio frequency transponder with improved read distance
US6249227B1 (en) 1998-01-05 2001-06-19 Intermec Ip Corp. RFID integrated in electronic assets
US6104291A (en) * 1998-01-09 2000-08-15 Intermec Ip Corp. Method and apparatus for testing RFID tags
US6441740B1 (en) 1998-02-27 2002-08-27 Intermec Ip Corp. Radio frequency identification transponder having a reflector
US6639509B1 (en) 1998-03-16 2003-10-28 Intermec Ip Corp. System and method for communicating with an RFID transponder with reduced noise and interference
US6459726B1 (en) * 1998-04-24 2002-10-01 Micron Technology, Inc. Backscatter interrogators, communication systems and backscatter communication methods
US6121878A (en) * 1998-05-01 2000-09-19 Intermec Ip Corp. System for controlling assets
DE19822443A1 (en) 1998-05-19 1999-11-25 Alcatel Sa Procedure for recording road tolls and registration point therefor
EP1950686B1 (en) 1998-08-14 2013-01-16 3M Innovative Properties Company Radio frequency identification method
EP1862982B1 (en) * 1998-08-14 2014-11-19 3M Innovative Properties Company Method of interrogating a package bearing an RFID tag
US6894601B1 (en) 1998-10-16 2005-05-17 Cummins Inc. System for conducting wireless communications between a vehicle computer and a remote system
US6107917A (en) * 1998-10-16 2000-08-22 Carrender; Curtis L. Electronic tag including RF modem for monitoring motor vehicle performance with filtering
US6201474B1 (en) 1998-10-21 2001-03-13 Intermec Ip Corp. Magnetic tape storage media having RFID transponders
US6100804A (en) * 1998-10-29 2000-08-08 Intecmec Ip Corp. Radio frequency identification system
US6236223B1 (en) 1998-11-09 2001-05-22 Intermec Ip Corp. Method and apparatus for wireless radio frequency testing of RFID integrated circuits
US6650230B1 (en) 1998-11-19 2003-11-18 Ncr Corporation Modulated backscatter wireless communication system having an extended range
US7194554B1 (en) 1998-12-08 2007-03-20 Nomadix, Inc. Systems and methods for providing dynamic network authorization authentication and accounting
US8266266B2 (en) 1998-12-08 2012-09-11 Nomadix, Inc. Systems and methods for providing dynamic network authorization, authentication and accounting
US8713641B1 (en) 1998-12-08 2014-04-29 Nomadix, Inc. Systems and methods for authorizing, authenticating and accounting users having transparent computer access to a network using a gateway device
US7571139B1 (en) 1999-02-19 2009-08-04 Giordano Joseph A System and method for processing financial transactions
US6456191B1 (en) 1999-03-23 2002-09-24 Exi Wireless Systems Inc. Tag system with anti-collision features
US7005985B1 (en) * 1999-07-20 2006-02-28 Axcess, Inc. Radio frequency identification system and method
US6714121B1 (en) * 1999-08-09 2004-03-30 Micron Technology, Inc. RFID material tracking method and apparatus
US6677852B1 (en) * 1999-09-22 2004-01-13 Intermec Ip Corp. System and method for automatically controlling or configuring a device, such as an RFID reader
SE515391C2 (en) * 1999-11-08 2001-07-23 Tagmaster Ab Identification tag and reader with interference protection
US6838989B1 (en) 1999-12-22 2005-01-04 Intermec Ip Corp. RFID transponder having active backscatter amplifier for re-transmitting a received signal
US7117374B2 (en) * 2000-03-24 2006-10-03 Intermec Ip Corp Apparatus and method for gathering and utilizing data
US6369710B1 (en) 2000-03-27 2002-04-09 Lucent Technologies Inc. Wireless security system
US6975228B2 (en) * 2000-04-17 2005-12-13 Tc (Bermuda) License, Ltd. Dual mode RFID device
US6806812B1 (en) * 2000-04-26 2004-10-19 Micron Technology, Inc. Automated antenna trim for transmitting and receiving semiconductor devices
US8266465B2 (en) 2000-07-26 2012-09-11 Bridgestone Americas Tire Operation, LLC System for conserving battery life in a battery operated device
US7161476B2 (en) 2000-07-26 2007-01-09 Bridgestone Firestone North American Tire, Llc Electronic tire management system
USRE47599E1 (en) 2000-10-20 2019-09-10 Promega Corporation RF point of sale and delivery method and system using communication with remote computer and having features to read a large number of RF tags
US20020183882A1 (en) * 2000-10-20 2002-12-05 Michael Dearing RF point of sale and delivery method and system using communication with remote computer and having features to read a large number of RF tags
JP4074518B2 (en) * 2000-10-20 2008-04-09 プロメガ・コーポレーション Method for managing multiple products in a cabinet with doors
US7253717B2 (en) * 2000-11-29 2007-08-07 Mobile Technics Llc Method and system for communicating with and tracking RFID transponders
US20020076819A1 (en) * 2000-12-14 2002-06-20 Bowman Danny Charles Paperless chain of custody evidence for lab samples
EP1362320B1 (en) * 2001-02-12 2011-02-09 Symbol Technologies, Inc. Radio frequency identification architecture
US7588185B2 (en) 2001-06-07 2009-09-15 3M Innovative Properties Company RFID data collection and use
US20030030542A1 (en) * 2001-08-10 2003-02-13 Von Hoffmann Gerard PDA security system
US6894615B2 (en) * 2001-10-09 2005-05-17 3M Innovative Properties Company Article with retroreflective and radio frequency-responsive features
US6758405B2 (en) 2001-12-19 2004-07-06 3M Innovative Properties Company Article with retroreflective and radio frequency-responsive features
US6825766B2 (en) 2001-12-21 2004-11-30 Genei Industries, Inc. Industrial data capture system including a choke point portal and tracking software for radio frequency identification of cargo
US6972682B2 (en) 2002-01-18 2005-12-06 Georgia Tech Research Corporation Monitoring and tracking of assets by utilizing wireless communications
US7009496B2 (en) * 2002-04-01 2006-03-07 Symbol Technologies, Inc. Method and system for optimizing an interrogation of a tag population
US6910911B2 (en) 2002-06-27 2005-06-28 Vocollect, Inc. Break-away electrical connector
TW200507579A (en) * 2003-06-10 2005-02-16 Matsushita Electric Ind Co Ltd License distribution method, information content providing method and relevant system
US7042359B2 (en) * 2003-08-23 2006-05-09 Sensormatic Electronics Corporation Method and apparatus to detect a plurality of security tags
US7321315B2 (en) * 2003-12-29 2008-01-22 Kimberly-Clark Worldwide, Inc. System and method for identifying disposable absorbent products
US20050224313A1 (en) * 2004-01-26 2005-10-13 Cubic Corporation Robust noncontact media processor
US7274910B2 (en) * 2004-02-09 2007-09-25 Battelle Memorial Institute K1-53 Advanced capability RFID system
US7841120B2 (en) 2004-03-22 2010-11-30 Wilcox Industries Corp. Hand grip apparatus for firearm
US20050261970A1 (en) * 2004-05-21 2005-11-24 Wayport, Inc. Method for providing wireless services
US7548153B2 (en) 2004-07-09 2009-06-16 Tc License Ltd. Multi-protocol or multi-command RFID system
JP4738771B2 (en) * 2004-07-29 2011-08-03 ルネサスエレクトロニクス株式会社 Communication system and communication method
US7644016B2 (en) * 2004-08-25 2010-01-05 Warsaw Orthopedic, Inc. Automated pass-through surgical instrument tray reader
US7118029B2 (en) * 2004-08-27 2006-10-10 Sdgi Holdings, Inc. Smart instrument tray RFID reader
US7366465B2 (en) * 2004-11-19 2008-04-29 Sirit Technologies Inc. Homodyne RFID receiver and method
US7199713B2 (en) * 2004-11-19 2007-04-03 Sirit Technologies, Inc. Homodyne single mixer receiver and method therefor
US7209040B2 (en) * 2004-11-19 2007-04-24 Sirit Technologies, Inc. Homodyne RFID receiver and method
US7227469B2 (en) * 2004-11-22 2007-06-05 Sdgi Holdings, Inc. Surgical instrument tray shipping tote identification system and methods of using same
US7492261B2 (en) * 2004-11-22 2009-02-17 Warsaw Orthopedic, Inc. Control system for an RFID-based system for assembling and verifying outbound surgical equipment corresponding to a particular surgery
US7492257B2 (en) * 2004-11-22 2009-02-17 Warsaw Orthopedic, Inc. Systems and methods for processing surgical instrument tray shipping totes
US7268684B2 (en) * 2004-12-08 2007-09-11 Sdgi Holdings, Inc. Workstation RFID reader for surgical instruments and surgical instrument trays and methods of using same
US7213767B2 (en) * 2005-02-23 2007-05-08 Sdgi Holding, Inc. Sleeve-type RFID tag
US7256699B2 (en) * 2005-03-24 2007-08-14 Sdgi Holdings, Inc. Button-type RFID tag
CA2603118A1 (en) * 2005-03-29 2006-10-05 Symbol Technologies, Inc. Smart radio frequency identification (rfid) items
US7474223B2 (en) * 2005-04-18 2009-01-06 Warsaw Orthopedic, Inc. Method and apparatus for implant identification
US20060244597A1 (en) 2005-04-28 2006-11-02 Sdgi Holdings, Inc. Surgical instrument tray RFID tag
US7362228B2 (en) * 2005-04-28 2008-04-22 Warsaw Orthepedic, Inc. Smart instrument tray RFID reader
US7837694B2 (en) 2005-04-28 2010-11-23 Warsaw Orthopedic, Inc. Method and apparatus for surgical instrument identification
US7741965B2 (en) * 2005-05-19 2010-06-22 Chung Nam Electronics Co., Ltd. Radio frequency identification (RFID) system
JP2007066107A (en) * 2005-08-31 2007-03-15 Fujitsu Ltd Apparatus, method and program for collating living body information
US7883420B2 (en) 2005-09-12 2011-02-08 Mattel, Inc. Video game systems
US20070080930A1 (en) * 2005-10-11 2007-04-12 Logan James R Terminal device for voice-directed work and information exchange
DE102005062827A1 (en) * 2005-12-27 2007-06-28 Bundesdruckerei Gmbh Document e.g. driving license, has antenna for transmission of data at frequency, and switching device, where data transmission is enabled in one switching condition of device and is disabled in another switching condition of device
US20070205896A1 (en) * 2006-03-02 2007-09-06 Axcess International Inc. System and Method for Determining Location, Directionality, and Velocity of RFID Tags
WO2007109241A2 (en) * 2006-03-20 2007-09-27 Axcess International Inc. Multi-tag tracking systems and methods
US20070239289A1 (en) * 2006-04-11 2007-10-11 Sdgi Holdings, Inc. System and software for processing containers having tools with associated transmitters
US8624721B2 (en) 2006-04-17 2014-01-07 Warsaw Orthopedic, Inc. Method and apparatus for embedding a transmitter into a tool, and a system for monitoring the tool
WO2007133690A2 (en) * 2006-05-11 2007-11-22 Axcess International Inc. Radio frequency identification (rfid) tag antenna design
US7965185B2 (en) * 2006-06-13 2011-06-21 Warsaw Orthopedic, Inc. Insertable form factor for an instrument tray
US8994533B2 (en) * 2006-11-30 2015-03-31 Patent Navigation, Inc. Conditional RFID
US8836481B2 (en) * 2007-01-08 2014-09-16 Quotainne Enterprises Llc Transponders and methods for operating a transponder
US20080212303A1 (en) * 2007-03-02 2008-09-04 Warren Farnworth Device for reducing or preventing exchange of information
US7710275B2 (en) 2007-03-16 2010-05-04 Promega Corporation RFID reader enclosure and man-o-war RFID reader system
EP2026530A1 (en) 2007-07-12 2009-02-18 Wayport, Inc. Device-specific authorization at distributed locations
US20090058609A1 (en) * 2007-09-05 2009-03-05 Clayman Henry M Coupon provided with rfid tag and method of using the same
US20090108998A1 (en) * 2007-10-26 2009-04-30 Lockheed Martin Corporation Automatic reporting of configuration of a remote unit
JP2009140254A (en) * 2007-12-06 2009-06-25 Toshiba Tec Corp Radio communication device
USD626949S1 (en) 2008-02-20 2010-11-09 Vocollect Healthcare Systems, Inc. Body-worn mobile device
US8079132B2 (en) * 2008-03-11 2011-12-20 Henry Clayman Method for shielding RFID tagged discarded items in retail, manufacturing and wholesale industries
US8638194B2 (en) * 2008-07-25 2014-01-28 Axcess International, Inc. Multiple radio frequency identification (RFID) tag wireless wide area network (WWAN) protocol
WO2010042055A1 (en) * 2008-10-10 2010-04-15 Milux Holding S.A. Charger for implant
US8386261B2 (en) 2008-11-14 2013-02-26 Vocollect Healthcare Systems, Inc. Training/coaching system for a voice-enabled work environment
JP2010164555A (en) * 2008-12-18 2010-07-29 Panasonic Corp Radio distance measuring system and radio terminal
US8116897B2 (en) * 2009-02-20 2012-02-14 Henry Clayman Method for manufacturing multi-piece article using RFID tags
US9125005B2 (en) * 2010-04-30 2015-09-01 Nokia Technologies Oy Method and apparatus for providing mobile services outside of cellular coverage
TWI410342B (en) * 2010-06-15 2013-10-01 Method and system for transmitting and receiving vehicle information
US8659397B2 (en) 2010-07-22 2014-02-25 Vocollect, Inc. Method and system for correctly identifying specific RFID tags
USD643400S1 (en) 2010-08-19 2011-08-16 Vocollect Healthcare Systems, Inc. Body-worn mobile device
USD643013S1 (en) 2010-08-20 2011-08-09 Vocollect Healthcare Systems, Inc. Body-worn mobile device
US9396367B2 (en) 2013-02-05 2016-07-19 Amtech Systems, LLC System and method for synchronizing RFID readers utilizing RF or modulation signals
US10121289B1 (en) 2014-04-11 2018-11-06 Amtech Systems, LLC Vehicle-based electronic toll system with interface to vehicle display
US10628723B2 (en) 2018-07-10 2020-04-21 Datamax-O'neil Corporation Methods, systems, and apparatuses for encoding a radio frequency identification (RFID) inlay

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8420893D0 (en) * 1984-08-16 1984-09-19 Buttemer D A Transponder
US4739328A (en) * 1986-07-14 1988-04-19 Amtech Corporation System for identifying particular objects
US4740792A (en) * 1986-08-27 1988-04-26 Hughes Aircraft Company Vehicle location system
JPS63226752A (en) * 1987-03-16 1988-09-21 Omron Tateisi Electronics Co Data writing system for id system
JPS63228852A (en) * 1987-03-17 1988-09-22 Omron Tateisi Electronics Co Communication control system for id system
CA1335676C (en) * 1988-01-14 1995-05-23 Akira Iga Portable data transmitter device and a system using the same
US4888591A (en) * 1988-10-06 1989-12-19 Amtech Technology Corporation Signal discrimination system

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EP0438250B1 (en) 1996-06-19
EP0438250A1 (en) 1991-07-24
AU6867291A (en) 1991-07-18
PT96486B (en) 1998-07-31
JP2977629B2 (en) 1999-11-15
US5030807A (en) 1991-07-09
ES2089121T3 (en) 1996-10-01
CA2033868A1 (en) 1991-07-17
JPH04218789A (en) 1992-08-10
PT96486A (en) 1992-09-30
AU629153B2 (en) 1992-09-24
IL96883A0 (en) 1992-03-29

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