GB2181326A - Electronic surveillance using self-powered article attached tags - Google Patents

Abstract

An electronic article surveillance system of type employing alarm tags releasably attachable to articles to be monitored, eg in a shop, comprises a transmitter unit (36) which radiates signals containing diverse message contents and tags (20). Each tag includes a pin type attachment device for releasably securing the tag to an article and incorporating switches 84, 86, 87 responsive to the state of the tag, a receiver (104) for receiving such radiated signals, a message decoder (120) for decoding the messages therein, a controller (90), an audio sequencer (128) and driver (132) having a piezo-electric output component and constituting an audible alarm unit, a switch monitor (82) for monitoring the switches 84, 86, 87, a retransmit sequencer (106) and tag antenna driver (144). The system is responsive to the state of the attachment device and to decoded messages for selectively operating the alarm unit to provide sensible output alarm indication. The messages may further be indicative of article identification and pricing, and the tags may effect display of price. An inventory store may be decremented upon check out of a tag carrying article, also an article price totalizer may be incremented. <IMAGE>

Description

SPEICIFICATION Electronic surveillance using self-powered article attached tags The present invention relates generallyto antipilferage and pertains more particularlytoelectronic article surveillance of the type involving communication between receptor receiver devices attached to articles and surveillance control apparatus. The invention relates also to electronics article surveillance (EAS) systems having related inventory and price control systems and methods.

Methods and systemsforthe purpose at hand which have seen primary commercialization are of type involving passive article attached devices, i.e., of type not including power sources. Such devices have, in prior Specifications, been termed receptor-reradiators and are adapted to reradiate or retransmit energy incidentthereon in preselected relation thereto. By way of example, article tags have included radiatorreceptordevices having an antenna,for receiving microwave and modulated low-frequency energy transmitted into and beyond a surveillance orcontrol area, and a nonlinear element, such as a diode, directly connected to the antenna. The radiator receptoroutputenergyistherebya reradiation of the microwave and modulated low-frequency incident energy.

As is well known, radiation pattern control, in relatively small areas, such as retail establishments, libraries, etc., is difficult in proportion to increase in the frequency level. The microwave energy is quite difficult to control in pattern. Thus, the industry has looked to the microwave as a carrier and to a lower, more pattern controllable, transmitted frequency radiated also in the area under coverage with a modulation characteristic, and to establishing alarm conditions based upon joint receipt and reradiation of the two diverse frequency incident energies. Alarm condition is sensed upon detection of the modulation characteristic of the low-frequency reradiated signal.

Despite the refined detection capability ofthe multiple frequency systems, and the pattern control aspect of the low-frequency transmissio n in the described systems, a degree of ambiguity can still attend same, based on the variation from intended pattern ofthe relatively controllable low4requency transmission. The desired, well-defined line of demarcation as between the surveillance zone and adjacent article display zones is at times not attained and this gives rise, on occasion, to incorrect alarm indication in intended display areas and corresponding diminution ofthe usable display area.

Plural low-frequency modulated signals have been considered, and a quite recent development has looked to the selective de-sensitizing of a receiver as respects signals reradiated from the article display area by use of unmodulated auxiliary low-frequency transmissions, for defining the demarcation line and enhancing display area usage.

Based on the possible ambiguities in the foregoing practices and systems, the industry continues to look to alternative approachesto the above, including use of independently-powered article affixed devices having safety-pins or like mechanically responsive alarmirig apparatus, as in United States Patent Specification No.3,713,133, and British Patent Specification No.

2,137,391. In the system. disclosed in British Specification No. 2,137,391,the article-attachable tag unit (alarm device) has a switch, which is operated upon efforts to remove the tag unit from the article, and an audible tone generatorwhich is activated upon such switch operation. Further, the tag unit has a receiving antenna and a related received frequency detector, which will also operate the alarm device. Atransmitter radiates energyatthe receiver detectable frequency into a control area forsurveillancethereof.

While the system and device disclosed in British Specification No.2,137,391 arethoughtto be viable as an alternative to the systems previously above discussed, in providing powered circuitry at the tag itself both for discernment of a specificfrequency and of removal of the tag to generate an alarm localized to the immediatetag location, such system and device are somewhat redimentary in character. For instance, the alarm device is disarmable only upon mechanical interfitting thereof with a "negator", typically located in a fixed position, e.g. at a checkout location. Further, such system contemplates only unidirectional transmission, i.e., to the tag alarm device. In brief, capabilities of usage of the above described system are limited by reason ofthe simplistic character ofthe device therein.

It is an object ofthe present invention to provide an improved system, method and apparatus for electro nicarticlesurveillancewhich overcomes some or all ofthe above disadvantages.

It is also an object ofthe invention to provide expanded operational capabilities in electronic article surveillance systems of type employing self-powered tags with alarm capability.

In its broadest aspect, the invention provides an electronic article surveillance system of type employing alarm tags releasably attachable to articles to be monitored in a retail installation orthe like, wherein the tags have enhanced operational capabilities giving rise to an improved likelihood of detection of article theft. To this end, the system has a transmitter unit which radiates signals containing diverse message contents. The tags each include an attachment device for releasably securing the tag to an article, a receiver unit for receiving such radiated signals and decoding the messages therein, an alarm unit and a signal processor, the latter being responsive to the state ofthe attachment device and to decoded messages for selectively operating the alarm unit to provide sensible output alarm indication.

In a preferred embodiment, the system includes transmitter in an exit area ofthe retail installation which radiates a signal containing an exit interrogate for receipt only by tags in such area and has a transmitter in a checkout area which radiates signals containing various selectable interrogate messages for article checkout purposes. Other transmitters may be provided, such as portable units for use bysecurity guardstoterminate alarm indications.

Tags assume various states in accordance with received and decoded messages and the state ofthe attachment devices. Thus, a tag may be in disarmed state, ready state, armed state, theft state and sleep state, as is explained in detail below. Further, each tag is adapted to communicate messages to a central monitoring station and iocal monitoring devices, such as may be placed in fitting rooms, receive tag transmissions and communicate such condition to the central station. Sensing units may be provided to respond to the tag output alarm indication to generate supplemental local alarm indication.

In a furtheraspect, tags have capability for issuing differenttypes of output alarm indication to signify different tag experiences.

Further, the system may include a secondary transmitter at the exit and checkout areas to effect highly localized and defined ranges in which the primary transmitter signals will be decodable to convey intelligence.

The invention also provides, for use in an article retail facility, in combination, an EAS tag of type responsive to incident energy comprising EAS messages and other messages related to pricing and identification of articles and including circuitry for responsetosuch EASmessagesandforthereceipt, storage and issuance of such pricing and article identification data, message generator apparatus for transmitting such EAS and other messages in the form oftag incident energy, and apparatus for interrogating the tags to cause such tag issuance of such stored pricing and identification data.

The invention further contemplates the use of an inventory store responsive to issuance of tag stored identification data to decrementthe inventory store and the use of article pricetotalizer apparatus responsive to the tag issuance of such stored pricing data. Further,thetag includes display apparatus for visual presentation of such pricing data.

In a preferred form, the tag includes circuitry in part commonly processing the EAS and other messages, inclusive of a message decoder for providing output indication ofthe nature ofthe received message.

Where the message received is of exclusive EAS nature, the invention contemplates corresponding EAS tag response and activity, such as output alarm indication. Where the received message is of other than EAS nature, the invention contemplates such pricing and/orinventorytag responsive and activity.

Desirably, the tag response may be joint in these support respects, i.e. upon receipt of selective EAS nature messages, the tag response is both in EAS nature and priceand/oridentification in character.

The present invention will now be described in greater detail by way of examples with reference to the accompanying drawings, wherein: Figure 1 is an illustration of a typical installation of a surveillance system in accordance with the invention; Figures 2 and 3 are block diagrams ofvarious transmitters which may be involved in the installation of Figure 1; Figure 4 is a block diagram of a preferred embodi ment of a tag system for use in the Figure 1 installation; Figure 5 is a separate showing ofthe controller of the Figure 4 tag system with indication of its various input and output signals; Figures 6(a), 6(b) and 6(c) illustratetheflow chart of the main program implemented bythecontrollerof Figure 5;; Figures 7(a), 7(b) and 7(c) illustrate the flow chart of the checkout subroutine of the main program implemented bythe controller of Figure 5; Figure 8 illustrates the flow chart ofthe fitting subroutine ofthe main program implemented by the controller of Figure 5; Figure 9 illustrates the flow chart of the sleep subroutine ofthe checkout subroutine ofthe main program implemented bythe controller of Figure 5; Figure lOis a series ofwaveforms showing the several signal formats involved in the transmissions ofthe system ofthe Figure 1 installation; Figures 11, 12 and 13 illustratethewaveforms of diverse alarm driving signals for use in practice ofthe invention; Figure 14 shows an arranement of primary and secondary transmitting antennae in accordance with the invention;; Figure 15 is a series ofwaveforms showing the various signal formats for the antenna arrangement of Figure 14; Figure 16 isa block diagram of an EAS pricing and inventory control system in accordance with the invention; and Figure 17 is a block diagram of a preferred embodi- ment of a tag receiver system in accordance with the invention.

Referring to Figure 1, installation 10 is a retail establishment including a display area 12 having fitting rooms 14 to its sides with fitting units 1 4a, a checkout station 16 having cashier and wrapping desks and associated transmitter units 1 6a and 1 6b and an exit area 18 having transmitter and receiver units 18a and 18b.Tags are indicated bytriangles at20 and audio sensing devices are noted at various locations bythecircles 22. Where tags 20 have transmit capability, as is preferred, the varioustransmitters will beconfigured as transceivers, having both transmit and receive function.

Checkout station transmitter unit 1 6a is shown particularly in Figure 2 as including wrap message generator 24 and wrap message selector 26. The system of the invention contemplates three different checkout modes, ActiveWrap, Audio Wrap and Passive Wrap, which will be understood from discussion below in connection with the checkoutflow chart offigures 7(a)-(c). Where Active Wrap is selected, generator 28 is operable by closure of switch 30 of selector 26. The output of generator 28 is conveyed over lines 34 and 36to checkout station transmitter 36.

Where Audio Wrap is selected, generator 38 is operable byclosure of switch 40 of selector26 and output is furnished over lines 42 and 34to transmitter 36. Likewise, where Passive Wrap is selected, gener- ator 44 is operable by closure of switch 46 of selector 26 and outputto transmitter 36 is over lines 48 to 34.

The checkout station further includes storage gener ator 50 operable upon closure of switch 52to apply a signal over line 54totransmitter36, such signal containing the "storage" message for placing a tag in storage. Terminate generator 56 is operable by closure of switch 58 to apply a signal containing the terminate message over line 60 to transmitter 36, such signal being effective to silence an alarming tag.

Exit generator 62 of exittransmitter unit 18a is operable atalltimesforconveying a signal containing the "exit" interrogate message over line 64to exit transmitter 66. Fitting receiver 68 offitting unit 1 4a is operable upon receiving a tag transmission to ener gizefitting unittransmitter72 over line 70, whereby a central or control station may be supplied with an alarm condition in such sequestered area.

In Figure 3 is shown portable unit 74. Closure of its switch 74a gives rise to generator 76 applying to portable transmitter 78 a signal containing the "ter minate" message.

Tag system 80 of Figure 4 includes switch monitor 82 which looks to the state of a tag attachment device, typically, an attachment pin, represented by switch 84, and to the state of a further switch 86, which changes state upon an attack on thetag, e.g. application of crushing force thereto. Upon change in state of either of the switches 84 or 86, switch. monitor 82 indicates same on the corresponding one of lines 88a and88b to controller 90. Afurtherswitch 87 may be included in the tag which is sensitive to motion of the tag and may also be looked at by monitor 82. Where the motion switch is off, tag battery life may be conserved by interrupting the supply of powerto the tag.

Monitor82 applies a signal to line 92 upon closure of switch 84, i.e., indicative of placement ofthe tag in active use, to clock pulse generator 94. Such start-up signal is for purposes of conservation of the battery which powers the tag system. On receiptthereof, generator 94 issues clock pulses on line 96 and furnishes wake-u p indication over lines 98, 100 and 102 to receiver 104 and retransmit sequencer 106.

Receiver 104 is coupled by line 108 andcapacitor 10 to tag antenna 112.

The output of receiver 104 is applied over line 1 14to message decoder 116, which receives clock pulses over lines 118 and 120. The receiver also outputs indication of received and decoded interrogate messages over line 122 to retransmit sequencer 106.

Output lines 1 24a to 124f extend from receiver 104to controller 90 whereby the controller is supplied with received and decoded messages.

Controller 90 applies output control signals over lines 1 26a to 1 26cto audio sequencer 128, which receives clock pulses over line 127 and informs controller 90 of its activity over lines 1 30a and 1 30b.

Audio driver 132, which includes a piezoelectric audio output component, is provided with drive signals over line 134 by audio sequencer 128.

Controller90furnishes control signals over line 136 to retransmitsequencer 106 and the latter informs controller t0 of its activities over line 138.

Sequencer 106 furnishes a stop signal over line 140 to clock pulse generator 94and applies output signals governing tag retransmission to antenna driver 144 over lines 146a and 146b.

The input and output signals of controller 90 are collected in Figure 5 with literal indication of the type of signal and its origin line from Figure 4. The decoded messages, shown at the left input to controller 90 include Active Wrap, Audio Wrap, Passive Wrap, Exit, Storage and Terminate signals. Atthetop input to controller 90 are shown the Pin Open/Closed and Attack signals. At the right of controller 90 are shown three differentsignalsforaudio output, namely, Alarm On/Off,Theft Warn and Check Warn signals. Below these signals are shown the repliesofthe audio output circuitry, 415 ms. Timeout and Check Warn Complete.

Below controller 90 are shown its outputto the retransmit sequencer, the Retrans On/Off signals, and the sequencer input to the controller, the 1.7 sec.

Timeout signal.

Implementation of controller 90 will be discussed in connection with the flow charts of Figures 6 to 9, from which tag and system experience will also be seen.

Turning to the main program, the same is entered in step 148 (Enter) of Figure 6(a) and starts with the tag in "disarmed" state (step 150- Place Tag and Disarmed State). In this state, the tag alarm is off as is its retransmitter (retrans). Various measures will place the tag in "disarmed" state, e.g., the "store" message.

The inquiry of step 152- ?Has Pin Been Closed -- is repeated on negative (N) answer and otherwise (yes -Y) leads to step 154-Place Tag in Ready State. The "ready" state is an interim ortransienttag state, commencing with the inquiry of step 156 -- ?Has Pin Been Opened. AtimU period for this inquiry is set by step 158- ?Has 13.2 Second Period Elapsed. lfthe pin is opened prior to the end ofthis period, return is made from step 1 56to step 150. Otherwise, on expiration of the period,the program advances to step 160-Place Tag in Armed State.

In the "armed" State, the tag alarm and retransmission are both off. Four paths of inquiry, as indicated by lines 162,164, 168 and 170,are cycled through atthis juncture, the first of which is set out in step 172 -- ?Has Exit Int. Been Received. Ifthe "exit interrogation" message is being received bythetag,the program advancesthrough step 174-Go to Exit-to the exit subroutine of Figure 8, below discussed.

In the second Armed State inquiry, step 176 is practiced-?Has Pin Been Opened. If the answerto this inquiry is affirmative, a warning is provided to the consumer in step 178-- OutputTheftWarn Signal. A shorttime period is measured in step 180-?Has415 ms. Period Expired. Fourteenths of a second arethus provided to permitthe consumerto discontinue further efforts at opening of the pin to remove the tag from the article. If the consumer discontinues the opening course of action, an affirmative answer will result from the inquiry of step 182-?Has Pin Been Closed, and line 184 will return the program to Step 160 above.

Should the consumer continue in pin removal, advance is made to step 186-Place Tag in Theft State. Here, the tag alarm is turned on as isthetag retransmission.This condition will persist until security personnel take the measure of step 188-?Has Terminate Alarm Int. Been Received, at which timethe program follows line 190 back to step 160 above.

Thethird path ofinquiryistostep 196- ?Has Wrap Int. Been Received. On positive answertothis inquiry, the program advances to its checkout subroutine of Figure 7, below discussed, through step 198-Go to Checkout.

Thefourth path of inquiry isto step 200-?Has Store Int. Been Received. On positive answertothis inquiry, the program returns via line 202 to step 150, whereby the tag is placed in "disarmed" state.

Turning nowto the checkoutsubroutine, the same is entered in Figure 7(a) in step 204-Checkout, wherein the tag alarm is off and its retransmission is on. As noted above, the invention provides user selection as to three diversecheckout modes. Inquiry is made asto thefirstrnode instep 206- ?ls Wrap lnt. Active Wrap.

Assuming an affirmative reply to this inquiry, advance is to step 208 -- ?Has 1.7 Sec. Period Elapsed. This provides a time window of almosttw6seconds during which a clerkatthe checkoutdeskshould open the pin and remove the tag from the article for storage thereof. Ifthe clerk does so, positive reply exists then asto the inquiryofstep 21 0-?Has Pin Been Opened, and advance is to step 212-Place Tag in "Disarmed" State.

If the inquiry of Step 210 is answered in the negative following thetime period of 208, advance is through step 213, Output Check Warn Signal, to step 214-Go to Step 160, i.e. thetag is returned to "armed" state.

Upon subsequent receipt of an exit instruction, the tag will alarm and retransmit. Thus, this checkout mode adopts the premisethat no tag will leave the retail installation.

lftheanswertothestep206inquirywas negative, i.e., that the checkout mode in use was not Active Wrap Int. Audio or Passive Wrap. If, for any reason, the answerto this inquiry is negative, the tag is directed to step 160 armed-state in step 214. Otherwise, advance isto step 218-?Kas'Pin Been Opened. Ifthe pin has been opened bythe clerk, flow is to step 220-Go to Step 150 and the tag is placed in "disarmed" state.

If the inquiry of step 218 is answered in the negative, advance is through line 222 into Figure7(b) and step 224-?Has 1.7 Sec. Period Elapsed. Upon expiration ofthis period, practice is made of step 226- Output CheckWarn Signai.

Steps 216 to 226 are common to both Audio Wrap and Passive Wrap checkout modes. In step 228-- ?Is Wrap Int Passive Wrap, inquiry is made to distinguish these checkout modes and subsequent handling of tags. A negative aliswerto step 228, indicating that the modest hand is Audio Wrap, advances practice to step 230-Place Tag in Armed State. Accordingly, the above premise common to the Active Wrap mode is adopted also in the Audio Wrap mode, the Audio Wrap mode including alsotheCheckWarn Signal.

If the inquiry of step 228 is answered in the affirmative, flow is to step - Passive State, retransmission on an alarm off. Continuation of the Passive Wrap checkout mode leads to the inquiry of step 234-?Has Store Int. Been Received, positive reply to which advances practice to step 236-Place tag in Disarmed State. On negative replytothestep 234 inquiry, flow is to step 238- ?Has Pin Been Opened, positive answerto which leads to step 240 Goto Step 178 and output ofthetheftwarn signal. On negative answer to the step 238 inquiry, flow is to the inquiry of step 242-?Has Wrap Int. Been Received.

Positive answer to the step 242 inquiry advances practice over line 246 to Figure 7(c) and step 248-Go to Checkout Negative answer to the inquiryofstep 242 leads over line 244 to the inquiry of step 250 ?Has Exit Int Been Received. Affirmative replyto this inquiry leadsto step 252-Go to Sleep.

The exit subroutine of Figure 8 is entered instep 254 -Turn Alarm On, Retrans On. This tag condition continues until satisfaction ofthe inquiry of step 2612- ?Has Terminate Alarm Int. Been Received. On positive response to this inquiry, flow isto step 260-Place Tag in "armed" State.

Turning nowto Figure 9, the tag sleep subroutine, which flowsfrom the checkoutsubroutine in the Passive Wrap checkout mode, is entered in step 272 Sleep. Inquiry is made in step 274 -- ?Has Store Int.

Been Received, and positive responsethereto leads to step 276-Place Tag in Disarmed State. Inquiry is also made in step 278- ?Has Wrap Int. Been received, affirmative response to which leads to step 280-Go to Checkout.

Figure 10(a) shows a twelve slottime scale, T1 to T1 2, in which each ofthe twelve slots occupy4.05 milliseconds, thetotal time scale being 4.86 milliseconds. In Figure 10(b), there is shown the system signal transmission containing the messageforActive Wrap checkout mode, comprising the digital format 101011001101. In each time slotof"1" designation, sixteen cycles of carrier are transmitted, for example, each cycle of 39.5 KHz, and in each time slot of "0" designation, carrier is nottransmitted.Time slotsT1 to T7 are dedicatedto the preamble oftransmitted signals, i.e., a pattern (1010110) which the receivers of tags must discern priorto considering the message of thetransmitted signals. Time slotsT8 to T1 2 comprise five slots in which the various messages or instruction words to be conveyed to tags are defined by permutative use ofthe time slots. The message pattern forthe Active Wrap interrogation orsignal is thus 01101 as in Figure 10(b). The message pattern forthe Audio Wrap signal is 01011 as in Figure 10(c).The message pattern forthe Passive Wrap signal is 10100 as in Figure 10(d).

The message patternforthe Exitsignal is 01010 as in Figure 10(e). The message pattern for the Storage signal is 10010 as in Figure 10(f). The message pattern for the Terminate Alarm signal is 10011 as in Figure 10(g). The message pattern forthe Fitting signal is 10101 asin Figure 10(h). Figure 10(i) indicatesthe separation as between the preamble PR and the instruction word IW of system transmissions totags.

As noted above, the invention lookstoavarietyof audio output signals from its tags. Figure 11 shows the output alarm indication selected fortheftwarning, a periodic audio drive signal which may have ON periods, indicated by positive pulses, each of 104 milliseconds, and OFF periods, occurring between successive ON periods, also of 104 milliseconds.

Audio output occurs at,for example, 3291 Hz, during On periods. The rightwardmost pulse in Figure 11 is shown as foreshortened, as by reason ofthe occur ence of a "terminate alarm" signal.

Figure 12(a) illustrates a second variant ofaudio drive signal wherein two bleeps will be provided to indicatethe "theftwarn" condition above discussed.

The ON periods are indicated again by positive pulses, each of 104 milliseconds during which audio output at 3291 Hz line. Figure 12(b) showsthe Theft Warn complete sigfnal, occurring at some 415 milliseconds afterthetwo audio drive pulses.

In Figure 13(a) is shown the above-noted Check Warn audio drive signal, comprises of a periodic train offour ON periods indicated by positive pulses, each of 104 milliseconds during which audio output at 3291 Hz occurs, and OFF periods of 726 milliseconds between successive ON period pulses. Figure 13(b) illustrates the "checkwarn complete" signal, which occurs on completion ofthefourth ON period.

Priorto discussion of the antenna arrangementof Figure 14, it will be helpful to reflect back on the outset introductory remarks with respect to the problems in prior art surveillance systems of type employing radiant energy transmissions to alarm tags. As therein noted, it is evidently desirable to define clear lines of demarcation as between intended article display areas, exit areas and checkout stations. On occasion, the exit and checkouttransmissionsthus have caused output alarm indication bytags located in the article display areas.

Figure 14illustrates an antenna arrangement which might be arranged centrally in the exit area of the Figure 1 installation, as contrasted with the sideward exittransmitter units 18a and 18b, and configured to avoid spurious transmission ofthe exit interrogation into the checkout area. Primary antenna 282 transmits the exit signal of Figure 10(e), 101011001010, which repeated in Figure 15(a).The radiation pattern of antenna282,which maybetermeda primary antenna, is shown generally by the boundary line 284, extend- ing into area adjacent the exit which desirably is for use in the checkout function. In accordance with the present invention, a secondary antenna 286 is introduced and is fed with the transmission signal of Figure 15(b), whose digital format is 0101001 10101,thefull complement of the Figure 15(a) signal.

Given the respective complemental transmissions of primary and secondary antennae 282 and 286, a quite refined line of demarcation 288 is defined whereby articles displayed in the zone between line 288 and 284 are protected from spurious alarm indication. Thus, tagged articles in such zone will receive the signal shown in Figure 15(c), which is deprived of both premable and instruction word intelligence.

As isshown in Figurel5(d),thetransmissionfrom secondary antenna 286 need not complement the preamble, butonlythe instruction word ofthe primary antenna transmission. Here, the secondary antenna transmission is muted during the preamble portion of the primary antenna transmission and simply complements the instruction word transmission thereof.

There results, as in Figure 15(e), the receipt and decoding by tags of the preamble portion ofthe system transmission, but a meaningless (unused) instruction word (11111).

Further alternative in message transmission in accordance with the invention would employ transmitting antennae position opposite one another and transmitting into the space therebetween and behind the antennae. Each antenna transmits one half of the message and is quiet during the transmission ofthe other. Tags between the antennae receive the total transmitted message,whereastags not located between the antennae will receive only one-half ofthe transmitted message and will accordingly be unresponsive.

As will be seen from the foregoing, the invention provides in one aspect an electronic surveillance system oftype employing alarm tags releasably attachable to articles to be monitored in an installation, the system comprising: transmitter meansfor radiating signals containing respective different mes sages for the tags, a plurality of alarm tags, each having attachment means for releasably attaching the tag to an article and providing output indication of the attachment state thereof, receiver means for receiving such radiated signals and for decoding the message contained therein, and tag controller means connected to the attachment means and to the receive means for selectively generating an output alarm indication responsivelyto the attachment means indicated state and such decoded messages.

The installation may include an articlecheckout area and an exit area, and the transmitter means includes respective checkout and exit area antennae for radiation of signals containing diverse ones ofthe different messages.

The tag controller means may generate the output alarm indication unconditionally upon receipt ofthe signal radiated by the exit area antenna. Likewise, the tag controller means may generate the output alarm indication unconditionally upon opening state of the attachment means under consumer acting upon same in the display area. The tag controller means may generate the output alarm indication unconditionally upon opening state ofthe attachment means and concurrent non receipt ofthe signal radiated by the checkout area antenna. However, the tag controller means may be further operable to awaitthe expiration of a predetermined time period following receipt of the signal radiated by the checkout area antenna prior to generating the output alarm indication responsively to the state ofthe attachment means.

One of the signals radiated by the transmitter means may contain a message indicative of termination of tag output alarm indication, the tag controller means being operable upon receipt of such termination message signal to discontinue output alarm indication.

Another of the signals radiated by the transmitter means may contain a message indicative of storage of the tag in non-alarming condition, the tag controller means being capable upon receiptof such storage message signal to renderthe tag inoperative to render the output alarm indication.

The installation may include a sequestered area (fitting room) for consumertaking of the articles and a receiverfor receiving tag transmissions. Upon receiving such retransmission, the fitting receiverforwards such indication, by transmission or hard wiring to a central control station.

The system mayfurther include sensor means for providing output indication ofthe sensing thereby of the tag output alarm indication. This indication is preferably an electrical signal which may be conveyed to a central monitoring station.

The tag output alarm indication is preferably an audible indication and the sensing means maythen comprise a transducer responsive to receipt of such audible indication and generating an electrical output signal in response thereto. As noted, the tag controller means provides plural different such alarm output indications and same are provided selectively in response to opening state ofthe attachment means and to different ones of the radiated signals.

Inthe preferred embodiments, thetag controller means mayfurtherincludetagtransmitter means for selective radiation of signals upon receipt of interrogate messages.

Finally, primary and secondary antennae may be employed,transmittingfull opposed complemental messages, partially opposed complemental messages or respective fractions of messages to define tight lines of demarcation as between different installation areas of interest.

Referring to Figure 16, composite support system 300 includes an EAS tag system 302 having a receiver/transmitter (RX/TX) unit 304, EAS circuits 306, prices and article identification (ID) circuits 308 and a display unit 310, interconnected by lines 312, 314,316,317 and 318, as indicated.

EAS tags 302 are provided in form selectively, releasably attachable to articles forwhich surveillance is desired, and may include attachment devices, such as safety pin type structures known in the art, the opening of which gives rise to discernible electrical circuit change.

Other components ofthe Figure 16 systems include: EAS message generator 320, connected by line 322 to transmitter 324; checkouttotalizer unit 326, connected by line 334 to receiver330; and inventory control unit 332, connected by line 334 to receiver 330.

In overall scheme, a plurality of EAS tags 302 are in cooperative supportwith the remainder of system 300, receiving incident energy transmissions oftrans mitter324and providing outputtransmissionsto receiver 330. Tag system 302 will further include an EAS message receiving and processing system, discussed above in connection with Figures 1 - 15.

A preferred system rendition of EAS tag 302 is shown in Figure 17. RX/TX unit304furnishes its output (received) signals over lines 312 to 314to message decoder 344 which provides output to the remainder of EAS circuits 306 of Figure 16 and over line 317a to WRAP message detector348, and over line 31 7b to tag store input/update detector 350, which are components of price and article ID circuits 308 of Figure 16.

WRAP messagedetector348 provides one inputon line 352 to coincidence detector354, another input to which is provided on line 356, this being a signal indicativeofthestate of the EAStag attachment device.

RAM (random access memory) interface 358 ofthe tag system is supplied on line 360 with the output of coincidence detector 354, and on line 362 with the output oftag store/input/update detector 350.

Each tag system includes an article identification (ID) RAM 364 and a price RAM 366. RAM 364 communicates with interface 358 over lines 368 and RAM 366 communicates with interface 358 over lines 370. lnterface-358 is connected to RXITX unit 304 over lines 312 and 316. Display unit 310 is operativeto displaythepricestored in price RAM 366 upon input over line 318a from price RAM 366 and concurrent input over line 318b from interface 358.

In the Figure 16 system and particularlythe Figure 17 tag system, in such preferred indicated form, one operational mode is that of tag system article price readout.

Generator 320 applies a signal having a preamble forthis mode, followed by article identification and price, to line322 and transmitter 324 applies the signal to one or more EAS tagsto be assigned to such article.

The received signal is applied by tag RXTTX 304to message detector 344, which applies all received messages to over line 317a tq wrap message detector 348.

As is shown above in Figure 10, the EAS messages have preambles,followed by a five-bit pattern indicating the nature ofthe message, such pattern identifying several WRAP tcheckout) messages. Indication of such message receipt is provided on line 352. In the course of article checkout, the clerk will open the tag attachment pin to remove the tag from the article.At this point, coincidence detector 354 will generate output on line 360 to which RAM interface 358 is responsive to retrieve the article identification code signal from RAM 364 and article price signal from RAM 366 and applies same over lines312 and 316to be transmitted from RXITX 304 to receiver 330, which is structured to discern preambles assigned thereto and detectthe price and article identification in the received signals, whence this data isfurnishedto units 326 and 332 of Figure 16.

In another operation mode,thetag system of Figure 17 functions to enter information in tag RAMs 364 and 366. In this mode, generator 320 of Figure 16 is operative, transmitting from unit 324 a preamble assigned to storing and updating the price of a given article or group of articles along with article identification and pricing data. Tag receiving such transmission have same furnished over iine 317b from message decoder344to tag store input/update detector350.

Detector 350 so advises RAM interface 358, which then furnishes the received article identification and pricing data to RAMs 364 and 366 for storage and subsequent issuance in the tag system article price readout mode previously discussed.

Display 310, which may be a liquid crystal display (LCD), receives stored price data over line 31 8a from RAM 366 and displays same responsivelyto a signal on line318bfrom RAM interface 358, which would be furnished constantly, except during updating or prior to price data initial storing.

An EASsystemandtagsystemthereof,which is supportive ofthe composite systems of Figures 16 and 17 is preferablythat of Figures 1 - 15 expanded in message reception and detection, and transmission to accommodate the foregoing price and article identification messages.

Claims (1)

1. An electronic surveillance system of type em ploying alarm tags releasably attachable to articlesto be monitored in an installation, said system including: (a) transmittermeansforradiating signals con- taining respective different m essages fa r sa id tags; (b) a pluralityofalarm tags, each having (i) attachment means for releasably attaching said tag to an article and providing output indication of the attachment state thereof; - (ii) receiver means for receiving such radiated signals and for decoding the message contained therein; and (iii) tag controller means connected to said attachment means and to said receiver means for selectively generating an output alarm indication responsivelyto said attachment means indicated state and such decoded messages.

2. A system according to claim 1, wherein said installation includes an article checkout area and an exit area, said transmitter means including respective checkout and exit area antennae for radiation of signals containing diverse ones of said different messages.

3. A system according to claim 2, wherein said tag controller means generates said output alarm indication unconditionally upon receipt of said signal radiated by said exit area antenna.

4. A system according to claim 1, wherein said tag controller means generates said output alarm indication unconditionally upon opening state of said attachment means.

5. Asystem according to claim 3,wherein saidtag controller means generates said output alarm indication unconditionally upon opening state of said attachment means and concurrent nonreceipt of said signal radiated by said checkout area antenna.

6. A system according to claim 5, wherein said tag controller means is further operable to awaitthe expiration of a predetermined time period following receipt of said signal radiated by said checkout area antenna priorto generating said output alarm indication responsively to the state of said attachment means.

7. A system according to claim 1, wherein one of said signals radiated by said transmitter means contains a message indicative oftermination of tag output alarm indication, said tag controller means being operable upon receipt of such termination message signal to discontinue output alarm indication.

8. Asystem according to claim 1, wherein one of said signals radiated bysaidtransmitter means contains a message indicative of sto rage of sa id tag in non-alarming condition, said tag controller means being operable upon receipt of such storage message signal to render said tag inoperative to rendersaid output alarm indication and includes electrical signal transmitter means operable upon tag alarm condition to generate output, said system additionally including a sequestered area for consumer taking of said articles, said sequestered area including a receiver for the receipt of said electrical transmitter means output.

10. A system according to claim 1, wherein said system further includes sensor means for providing output indication of the sensing thereby of such tag output alarm indication.

11. Asystem according to claim 10, wherein said tag output alarm indication is an audible indication, said sensing means comprising a transducer responsive to receipt of said audible indication and generating an electrical output signal in response thereto.

12. Asystem according to claim 1,wherein said tag controller means provides plural different such alarm output indications.

13. A system according to claim 12, wherein said different alarm output indications are provided selectively in response to open state of said attachment means and to different ones of said radiated signals.

14. A system according to claim 1, wherein said tag controller means further includes tag transmitter means for radiation of signals selectively in accord ante with receipt of certain of said messages.

15. A system according to claim 1, further including secondarytransrnitter means for radiating a signal of complementai characterto that radiated by said first-mentioned transmitter means.

16. A system according to claim 15, wherein said signal radiated by said first-mentioned transmitter means comprises a preamble portion and a message portion, said signal radiated by said secondary transmitter means having a preamble portion and a message portion.

17. A system according to claim 16,wherein said preamble portion and said message portion of said signal radiated by said secondarytransmitter means are complemental respectively to said preamble portion and said message portion of said signal radiated by said first-mentioned transmitter means.

18. A system according to claim 15,whereinsaid system is located in an installation having a first controlled area and an adjacent second controlled area and wherein said message contained in said signal radiated by said firsttransmitter means is a message intended for receipt and decoding by receiver means of tags located exclusively in the first controlled area, said first-mentioned transmitter means being located in said first controlled area and said secondary transmitter means being located between said first-mentioned transmitter means and said second controlled area.

19. A system accordingto claim 18, wherein said first controlled area is an exit area of said installation and wherein said second controlled area is a checkout area of said installation.

20. A system according to claim 1, wherein such radiated signals include messages relate to pricing and identification ofarticlesandwherein said tags include circuitryfor responseto such EAS messages and for the receipt, storage and issuance of such pricing and article identification data, said system further including means for interrogating said tags to cause such tag issuance of such stored pricing and identification data.

21. A system according to claim 20, further including inventory store means responsive to such tag issuance of said identification data for selectively decrementing stored inventory content corresponding to said identification data.

22. A system according to claim 21, further including price totalizer means responsive to such tag issuance of said pricing data fortotalization thereof.

23. A system according to claim 20, further includ- ing inventorystore means responsive to such tag issuance of said identification data for selectively decrementing stored inventory content corresponding to said identification data and price totalizer means responsivetosuch tag issuance of said pricing data fortotalization thereof.

24. An electronic surveillance system constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.