GB2187021A - Token handling device - Google Patents

Abstract

A token handling device transmits, using an electromagnetic carrier, data, clock pulses and power to a token. The token transmits data by varying the degree of absorption of the carrier in synchronism with the clock pulses. These data transmissions are detected by a receiver in the token handling device, the sensitivity of which is adjusted each time a token is received. The token could be used in transactions in place of coins, or alternatively could be used for identification purposes in other areas. Data stored by the token could be used to change the way in which the token handling device operates. The token handling device may for example form a vending machine, and the token could be used to alter the pricing of goods vended thereby. The token handling device may be combined with a coin validator, in which case there is preferably a common path from an entrance slot for carrying both the tokens and the coins to appropriate testing apparatus.

Description

SPECIFICATION Tokens and token handling devices This invention relates to tokens and token handling devices.

The invention is particularly, although not exclusively, useful in the field of vending machines, gaming machines, amusement machines, pay telephones, change-giving apparatus and like machines which dispense something of valuer perform a service or function in exchange for money received from the user. Such machines will for convenience be referred to herein as coin operated machines. These machines generally handle a large volume ofcoins, which means that the machines need to have a large storage space for the coins, that the coins need to be regulariy collected and transported to a central location, and that they then need to be counted and delivered to a bank. This procedure is inconvenient and expensiveforthe owner of the machine.In addition, the user has to havecoinsavailablein orderto usethe machine, and would therefore need to carry out an inconveniently large number of coins if he wished to use the machine often. Hewould have to have the correct denominations of coins available unlessthe machine was of the change-giving type, and in the lattercase carrying the change around would be inconvenient.

Some of the machines referred to above, for example gaming machines, have been capable of handling special tokens in addition to genuine coins.

However these tokens have generally been treated in much the sameway as genuine coins.

The present invention is concerned with arrangements which can substantially mitigate the disadvantages referred to above by arranging for the machines to be able to handle, in place of or preferably in addition to genuine coins, data-storing tokens which can be used to authorise transactions of different values, and which are preferably returned by the machine so that the tokens can be repeatedly used.Two types of system cou Id be used: a debit system in which a user makes an initial payment for a token which stores therein data representing its value, the machine being operable to alter this stored data upon use of the token so asto reducethevaluebyanamountcorrespondingtothe value of the transaction; and a credit system in which the token stores data representing an account of the user, the machine being operable upon use of the token to note this account data so thatthe account can then be debited by an amount corresponding to the value of the transaction. In the latter case, the machine could be connected on-line to a central station which keeps the account information, or could store information which is regularly collected by means of data storage modules.

Allowing the user to operate the machine using a "debit" or "credit" token effectively avoids the problems referred to above relating to the handling and carrying of large numbers of coins.

It will be appreciated, however, that aspects of the invention have value in other fields. For example, the invention is also useful in the field of identification tags, wherein for example data-storing tokens could be used with automatic equipment for gaining access to areas restricted to authorised personnel.

Afirst specific aspect of the invention relates to a device which handles both coins and tokens storing data which can be determined upon communication between the device and the token, the device having a common path for receiving the coins and the tokens and for deiivering them to testing apparatus forvalidating the coins and communicating with the tokens.

The use of a common path has the advantage that the user can operate the machine using tokens in the same way as the machine is operated using coins, e.g. by inserting tokens and coins through the same slot. This feature also has the substantial advantage that, because it is not necessary to provide a separate entrance slot and path for the tokens, modifying the vast number of existing machines already in use so thattheycan additionally handle tokens is rendered much more simple.

The testing apparatus is preferably arranged to have two separate testing stations, one forvalidating the coins and the other for communicating with the tokens, the arrangement being such that only those items which are rejected by the first testing station are delivered to the second testing station.

It is preferred that the coin validator be the first testing station. This permits existing coin operated machines to be adapted to handle tokens without requiring any physical modification to the coin handling mechanism upto and including the coin validator. Instead, it is merely necessary to install the test station forthe tokens along the path taken by items rejected by the coin validator. This feature is particularly useful in that it is very common for coin mechanisms incorporating a coin validator and a separator for separating rejected items and genuine coins to form a unit, andforthesametype ofunitto be installed in different kinds of coin operated machines.In these circumstances, the coin path leading tothevalidator may vary substantially depending upon the machine in which the coin mechanism is installed. Ifthetoken interrogation station were to be installed in front of the coin validator, in some cases there may be insufficient room inthevending machine to permitthis modification without substantially changing the configuration ofthe coin mechanism itself. This is avoided in the preferred embodiment by installing the token testing station within the unit and along the reject path.

It is envisaged that in most public installations, the majority of items inserted into the device will be genuine coins, and that very few items which are neither genuine coins nor tokens will be inserted.

Thus, by arranging for coin validation to occur first, the majority of items delivered to each testing station will be appropriate for that station, so that the device operates in an efficient manner.

The device preferably has meansfortemporarily retaining the tokens within the device until a transaction is completed. If the token is a debit token, this feature is desired to enable the value stored in the token to be altered by an amount corresponding to the value of the transaction before being returned ta the user. If the token is a credit token, this feature is desirable, particularly in "multi-vend" machines which can be operated a number of times in succession without requiring the user repeatedly to insert coins or tokens, because retrieving the token would be a convenient way of signifying the end of a transaction or a series of transactions.A credit token could instead be returned immediately to the user after interrogation, butthis meansthatthe user would then have to perform some operation to advise the machine when his transactions are completed, and if he were to forget to do this the values of subsequenttransactions carried out by the other users would be deducted from his account.

The holding station at which the token is temporarily retained is preferably, like the token testing station, disposed after the validator and more preferably after separation by an accept/reject gate so thatthe station receives onlythose items which are rejected bythevalidator. In a particularly convenient embodiment, the token testing station and holding station are combined. This has the advantage that communication with the token can be carried out after the token has been halted atthe holding station.

The device preferably also has means for updating or otherwise altering the data in the token, or introducing new data into the token, which in the debit system would be used to alterthe token's value after a transaction has been carried out. The means for accomplishing this is preferably also disposed at the holding station, although in an alternative embodiment it could be disposed downstream of the holding station so as to update the data during the token's exit from the machine.

Preferably, meansforobtaining data from the tokens and means for updating information in the tokens are both disposed at the holding station. The two functions may be performed using common components.

According to a second specific aspect of the invention, a token storing alterable data which can be determined by communication with the token is substantially coin-shaped and sized. The token is such that itcan enterand passthrough astandard coin handling mechanism. This has a numberof advantages. It means that modifying existing coin operated machines so that they can additionally handlethe tokens is rendered much easier, because it merely involves fitting a means for communicating with the token to otherwise fairly standard equipment. For example, as described above, a testing station can be disposed along a reject path of the mechanism, so that the token passes through the validator, is rejected and then reachesthetesting station.This aspect of the invention also has the advantage that even if machines are intended to be used only with tokens, and pot with genuine coins, it is nevertheless possible to use standard coin handling mechanisms and techniques.

The token may contain its own power supply, but preferably is powered by energy transmitted by the token handling device.

The tokens used in the various aspects of the present invention are preferably arranged so that they and the device can communicate in a "contactless" manner. Various techniques can be used. For example, very low frequency radio transmission can be used to obtain data from, and if desired to pass data to, the token. British Patent Specifications Nos. 1,599,120 and 2,077,556A describe radio techniques for interrogation. Other methods, e.g. optical techniques, could alternatively be used.

One alternative technique, which is considered particularly advantageous, forms the subject of a third aspect of the present invention. In accordance with this aspect, a token handling device, referred to also as a token interrogator, has means for communicating with a token by determining how an electromagnetic field is absorbed by the token. The invention also extends to a token suitable for use with such a device. The token preferably has a field-absorbing circuit which can be controlled so as to alterthe degree or nature ofthe absorption.

In one embodiment described herein, this is a resonant ci rcuit whose resonant frequency can be switched between at least two values. The device may communicate with the token by generating an electromagneticfield of different frequencies, and more preferably of a continuously-swept frequency.

The device determines data stored in the token in accordance with the frequencies at which absorption of the field occurs. Preferably, the device determines the data in response to changes in the absorption frequency, so that is operates substantially independently of the specific resonance frequencies of the resonant circuit.

An alternative, preferred arrangement is also described herein. In this arrangement, the token is powered by an electromagnetic signal transmitted by the interrogator (preferably of a frequency around 100 kHz). The same signal as is used fortransmitting power is also used for communication between the token and the interrogator. Data is communicated to the token by selectively interrupting the power transmissions for brief periods. The token has power storing means so that these interruptions do not interfere with its operation. The token sends data to the interrogator by selectively coupling a low impedance across its receiving antenna. This alters the degree of energy absorption, which can be sensed by the interrogator. The data transmissions are preferably made at predetermined times, and to facilitate this a cloche signal is preferably used.

Preferably, the interrogatortransmits clock pulses in the same way as data pulses, and these clock pulses are used both for transmissions to the token and transmissions from the token.

In addition, in this arrangement, the token contains a non-volatile readable and writable memory (preferably an EAROM). This is desirably used for storing operational data such as the token value, but also has another use. In particular, it may be desirable in many circumstances to terminate the powertransmissionto the token before all the operations involving the token have been completed. This for example may be useful for reducing power consumption when the token is used in a pay phone installation; the token may be interrogated when first inserted to check its validity, whereupon the power is cut off forthe duration of the telephone call andthereafterreappliedtoallow the token value to be reduced by an amount corresponding tothe cost of the telephone call.Thus, on powering-up of the token, either of two sequences of operations of the token could be required (i.e. transmission of data to the interrogator, or receipt of data from the interrogator). The non-volatile memory in the token can be used to store a flag which indicates which part of the complete cycle of operations the token is in, and which is used to determine what actions are taken by the token upon powering-up.

This arrangement embodies a number of further independently inventive aspects, amongst which are: a) A system comprising a token which receives powerfrom an antenna and sends data by altering the impedance across the antenna (preferably by shorting-out orat least connecting a very low impedance across the antenna).

b) Atoken and interrogator between which two-way communication can be established using the same carrier signal, which signal originates from the interrogator (and preferably transmits power and/or clock pulses to the token).

c) Atoken and interrogator between which two-way com mu nication can be established, communication in both directions being synchronized with clock pulses transmitted by the interrogator.

d)Asystem comprising atoken powered by energy received from the interrogator, the token having a non-volatilewritable memory and being arranged to perform, following power-up, one of a plurality of sequences of operations dependent upon flag data stored in the memory, at least one ofthose sequences resulting in a change inthatflag data.

It will be appreciated that these aspects ofthe invention reside in the token and interrogator individually, as well as the combination thereof.

Thetoken handling device may have transmission and reception coilsfortransmitting and receiving the signal which is selectively absorbed by the token.

Alternatively, a single coil could be used for both these purposes.

In accordance with a still further aspect of the invention a token handling device is arranged for automatically altering its sensitivity to received transmissions in the presence of a token, and preferably each time a new token is received bythe handling device. This is particularly useful when the token transmits data by altering the degree of absorption of electromagnetic radiation, and even more useful when the token is powered by received electromagnetic energy, because in those circumstances the signals received by the token handling device may vary due to slight differences in the tokens, or slightly different positions of the tokens.This can be compensated for by adapting the receiver sensitivity to ensure that changed in absorption of the carrier transmitted by the token handling device are correctly received by the token handling device.

The device is preferably able to communicate with the token irrespective of the particular orientation of the token.

According to a further specific aspect ofthe invention,there is provided a token handling device which performs operations in accordance with operational data stored in the device, and which is capable of communicating with a token in orderto determine token data stored thereby, the device being operable to enter a first mode or a second mode in dependence upon the token data, the device being operable in the first mode to perform a said operation, and in the second mode to alter the operational data in a mannerdependentupon said token data.

It is envisaged that the device would normally be caused by entered tokens to perform operations (such as permitting access to certain areas, or in the case of vending machines and the like vending a product of performing a service), but could also have its operational parameters altered by entering a special token storing predetermined data. This would be useful for example if a vending machine owner wished to change the pricing data stored in hisvending machines. Hewould haveaspecially encoded token which would cause this to occur upon insertion into the vending machine, so that the pricing change could be achieved as easily, and using the same electronic components, as when using a token to purchase a product from the machine.

In the field of identification tokens, which may store a special code which when read out bythe device permits access to a particular area, it may be desired for security reasons to change the code which authorises access. This could be achieved very easily by using a specially encoded token which stores data such as to cause the device to enterthe second mode, in which information in the token is used to change a stored parameter so that in future the device will recognize a different security code as being appropriate for authorising access.

According to another specific aspect of the invention,there is provided a token handling device operable to receive and communicate with tokens in order to determine data stored thereby, and operable to perform a transaction and to alter the data stored bythetoken in accordance with a predetermined value associated with the transaction, the device being operable before performing the transaction to carry out a security code recognition operation to determine whether the token stores a security code which is appropriate to that machine, and to carry out the transaction only if the token stores such an appropriate security code.

Thus, vending machines, and like machines for dispensing products or performing services, can be designed so that they will accept tokens issued by a particular company, for example that owning the vending machines, but will not accept tokens issued by other companies, which tokens may be identical except for the security code stored therein. In this way, an owner of a chain of vending machines can ensure that he is paid for all the tokens used to obtain products from his machines.

Preferably, the token handling device itself must store a security code which is appropriateforthe token in order for transactions to be carried out. In this way, it can be ensured that a company's tokens will not havetheirvalues altered in an unauthorised manner by insertion into another company's token handling device.

The token handling device may be arranged additionailyto handle genuine coins.

In a preferred embodiment of the invention, aspects described above are combined to produce a token handling system of substantial advantage and utility.

Arrangements embodying the invention will now be described byway of example with reference to the accompanying drawings, in which: Figure lisa schematic view of a coin and token handling device according to the present invention; Figure2 shows a token in a testing station of the device of Figure 1; Figure 3 is a schematic block diagram of the circuitry of the token and the testing station in a first arrangement; Figures 4(a) and (b) are waveform diagrams for illustrating the operation ofthe circuitry of Figure 3; Figure 5is a block diagram showing the token handling device and token in a second arrangement; Figure 6 is a circuit diagram of a receiver of the token handling device of FigureS;; Figure 7is a diagram of the circuitry ofthetoken of Figure 5; and Figure8showswaveforms of signals received by the receiver of the token handling device of Figure 5.

Referring to Figure 1, the coin and token handling apparatus 2 includes a coin validator 4for receiving coins and tokens as indicated at 6 travelling along a common path 7from an entrance slot (not shown).

During the passage of the coins and tokens 6 along a path 8 in the validator 4, test operations are carried out to determine whether a valid coin has been inserted, and ifsothedenqmination of the coin.

These tests are standard ones, and mayforexample be inductive tests.

Acceptable coins then enter a coin separator 10, which has a number of gates (not shown) controlled by the circuitry of the device for selectively diverting the coins from a main path 12 into any ofa number of further paths 14,16 and 18, or allowing thecoinsto proceed along the path 12 to a path 20 leading to a cashbox. If the item tested in the validator 4 is not determined to be an acceptable coin, it is delivered to a reject path 30 instead of continuing through the separator 10.

Each of the paths 14,16and 18 leads to a respective one ofthree coin containers 22,24 and 26.

Each of these containers is arranged to store a vertical stack of coins of a particular denomination. A dispenser indicated schematically at 28 is operable to dispense coins from the containers when change isto be given by the apparatus.

Wheneveravalidatorrecognisesan acceptable coin, a credit count is incremented by an amount corresponding to the value of the coin. When sufficient credit has been accumulated, the device 2 produces a signal indicative of this. For example, in a preferred embodiment the device 2 is installed in a vending machine (not shown), and the signal will indicate to the vending apparatus that a user may initiate the vending of a product. The apparatus may be arranged to operate such that products can be repeatedly vended until the credit count drops to a level below the lowest ofthe prices of the products which the machinevends.

At any stage, the user may operate an "ESCROW" button, which terminates the transaction or series of transactions, and initiates the delivery of change of a value corresponding to the remainder of the accumulated credit, which credit is then cleared.

The arrangement described so far is quite conventional, and the details of particular structures suitable for accomplishing these functions will therefore not be described.

The device of Figure 1 has, in addition to these structures, a token testing or interrogation station 32, shown in more detail in Figure 2. This station 32 is situated along the reject path 30 so that all rejected items are delivered to the station 32 before being delivered to a reject tray for retrieval by the user.

Referring to Figure 2, the reject path 30 extends between a rearwall 34, a front wall which is not shown in Figure 2 to permit the interior of the interrogation station to be seen, and sidewalls 36 and 38. The rearwall 34 has an aperture 40 sothata gate 42 can be selectively thrust into and withdrawn from the path 30 by a solenoid 44.

Normally, the gate 42 is located in the path 30 so that all rejected items are stopped at the interrogation station 32. Each item is interrogated, and if it is found notto be a token, the gate 42 is withdrawn so that the item can proceed to the reject tray.

If the item is a token, it is held by the gate 42 atthe interrogation station 32 until the completion ofthe transaction orseries of transactions carried out by the user, following which the gate 42 is withdrawn so thatthe token is returned to the user.

Figure 2 shows a token 50 of a preferred embodiment of the invention, which is for use with debit systems and which therefore stores data representing a particularvalue,which value is decremented after a transaction or a series of transactions has been carried out and beforethe token 50 is returned to the user.

Figure 3 shows one example ofthe type of circuitry that can be used for the token and the interrogation station. It will be appreciated that many othertypes of circuit could alternatively be used.

The interrogation station 32 has transmission and reception coils 52 and 54, respectively. The transmission coil 52 is driven by a drive circuit 56 which is operated in responseto a signal derived from a microprocessor 58. The microprocessor 58 also receives, via an input circuit 60, and processes signals from the reception coil 54, and delivers signals to the main data bus 62 of the control circuit of the coin handling mechanism. The data bus 62, inputcircuit60 and drive circuit56 are connectedto the microprocessor 58 via a multiplexing circuit 64 which communicates with the microprocessor 58 via a data bus 66, an address bus 68, and a read/write signal path 70.The microprocessor 58 controls the reading of data from, and delivering of data to, the token 50, and also communicates with the main coin mechanism circuitry so as to send the token value to this circuitry and to receive therefrom the remaining value after a transaction or series of transactions has been carried out.

The main coin mechanism circuitry may be of per se known form, such as that described in published U.K. Patent Specification No.2,1 10,862A. In an alternative arrangement, the main processor of the coin mechanism circuitry could be used to control the interrogation station directly, so thatthe additional microprocessor 58 would not be required.

In orderto interrogate the token 50, the microprocessor 58 causes the transmitter drive circuit 56to drive the coil 52. The circuit 56 is so arranged thatthe outputfrequency used to drivethe coil 52 sweeps from a lowvalueto a highvalueeach time the circuit 56 is operated. The output frequency is shown in Figure 4(a).

The token 50 includes a circuit generally indicating at 72 for selectively absorbing the energy transmitted by the coil 52. In this particular case, the circuit72 is a resonantcircuitincluding a coil 74and a parallel-connected capacitor 76. Afurther parallel-connected capacitor 78 can be switched in and out of ci rcuit using a semiconductor switch 80 in order to vary the resonance frequency of the circuit 72.

The energy transmitted by the transmission coil 52 is picked up by the reception coil 54, andthesignal from this coil 54 is delivered to a comparator in the input circuit 60for amplitude-detection purposes.

The signal generated by the input circuit 60 is shown in Figure 4(b). It will be noted that each time the frequency ofthe signal delivered to the transmission coil 52 is swept, there is a point at which the energy is strongly absorbed by the resonant circuit 72, so that a short pulse is produced in the signal generated by the input circuit 60. The precise time, within each frequency sweep, at which this pulse is produced is dependent upon the resonance frequency of the circuit 72, and can therefore be altered by operation of the switch 80.

Transmission of data frqm the token 50 to the interrogation station 32 is achieved by selective operation of the switch 80, for example such that a data bit "1" is represented by the absorption frequency when the switch is closed, and a data bit "0" is represented by the absorption frequency when the switch is open.

This data can be detected by the microprocessor 58 in a variety of ways. For example, the microprocessor could be arranged to note when the interval between the pulses received from the circuit 60 alters from a value P1 (see Figure 4(b)), which is determined by the rate at which the drive circuit 56 is operated, to a value P2, which occurs when the resonance frequency has just been altered from its lowvalueto its highvalue,ortoavaluep3,which occurs when the resonance frequency has just been altered from its highvalueto its lowvalue.

Alternatively, the microprocessor could be arranged so that each time a token is received, the timetl (seeFigure4(b))fromthestartofthe frequency sweep to the time at which the circuit 60 produces a pulse is measured. During future frequency sweeps, the resonance frequency is determined to be low if the time taken for a pulse to be generated is substantially equal to t1,and is determined to be high ifthetime is a significantly greatervaluet2.

Neither of these methods relies upon the resonance frequency having specific values, so that large tolerances are permitted in the token circuitry.

Data is transmitted to the token 50 by amplitude-modulatingthesignal applied to the transmission coil 52. The amplitude modulated signal can either have a varying frequency, as in Figure4(a), ormaysimplyhave a singlefrequency, for example located atthe midpoint of the frequency sweep.

The signal is picked up by the resonant circuit 72, which has an output connected to a detection circuit 82. The circuit 82 isoperabletoderivefromthe received waveform the data transmitted by the interrogation station 32.

The circuit 80 can detect predetermined codes which are transmitted by the station 32. Detection signals indicative of these codes are delivered to a control circuit 84. The detection circuit 82 can also detect data intended for storage in the token 50. This data is delivered toa memorycircuit86.

In the present embodiment, the memory circuit 86 is a recirculating shift register, the contents of which are shifted back into the register as they are read out.

The control circuit 84 can cause data to be read out of the memory circuit 86 and delivered to a transmission circuit 88. The control circuit 84 causes the transmission circuit 88 selectively to operate the switch 80 in accordance with the data from the memory circuit 86, so that the data is sent to the interrogation station 32.

The operation of the circuitry is as follows. When a token has been received in the interrogation station, the drive circuit 56 is operated. This is detected by the token 50, which then sends to the station 32 a predetermined codewhich represents a requestfor the interrogation station 32 to transmit a security code which the microprocessor 58 stores.

This station security code is checked by the control circuit 84, and further operations are permitted only if the station security code is suitable for that token.

This procedure, which is optional, is done to ensure that any subsequent alteration ofthe data in the token onlytakes place if the machine containing the interrogation station 32 is an appropriate one, for example one owned buy a particularcompany.Thesta- tion security code recognition operation could for example be carried out by determining whetherthe code matches a number stored in the memory circuit 86; thiswould enable tokens havingthesamecir- cuits to be made suitable for different machines simply by altering the contents of the memory circuit 86.

Assuming that the station security code is appropriate for that token, the token then sends to the interrogation station 32 a token security code stored in the memory circuit 86. The microprocessor 58 determines whetherthis token security code is app ropriate for that machine, and only permitssubse- quenttransactions if the code is appropriate. This ensures that the machine cannot be operated by insertion of tokens supplied by unauthorised companies.

It will be noted that the token security code is trans- mitted only if the station security code has been found to be appropriate. This improves the security ofthe system, as it renders it difficu Itfor un- authorised people to determinethetoken security code.

Afterthe security code recognition operations, the token 50 proceeds to transmit a token value stored in the memory circuit 86. This could, if desired, be car- ried outonly after the interrogation station 32 has first acknowledged thatthe token security code is appropriate.

The microprocessor 58 then sends signals to cause the credit count to be incremented by the token value. The user is then permitted to carry out transactions in the same manner as if the credit count had been incremented by the insertion of coins.

Afterthecompletion ofthetransaction orseriesof transactions,the user operates an ESCROW button.

The device responds to this by delivering to the microprocessor 58 data representing the remaining credit. The interrogation station 32 then transmits this data to the token 50. The detection circuit 82 recognises a special code which has been added to the transmitted data, and this code causes the control circuit 84 to shift into the memory circuit 86 data from the detection circuit 82 representing the remaining credit. This data replaces the previouslystored token value. The token 50 then acknowledges receipt of the data, following which the device causes the retraction of the gate 42 and thus permits the token 50 to be returned to the user.

Tokens can be used with the device for a number of supplementary purposes. For example, by inserting in the memory circuit 86 of token a special code in place of or in addition to the token security code, the microprocessor 58 can be caused, upon detecting this code, to enter a special mode. In this mode, the microprocessor 58 extracts from the token 50 data which is then sent to the coin mechanism circuitry to alter a list of prices stored therein. This is a convenient way of handling changes in the price of productsvended by the machine.

In a similarfashion,the microprocessor58can be caused to enter a further mode used to changethe security code which the microprocessor 58 stores, so that in future different security codes would be recognised as appropriate for use with that device. A convenientway of achieving this latterfunction would be for the microprocessor to enter the further mode on receiving a first token storing the special code, butto waitfor receipt of a second token before actually changing its stored code. On receiving the second token, the security code stored in the microprocessor 58 is replaced by that stored in the token.

This arrangement has particularvalue when first installing machines, because itallows all machinesto be initialised by using the same token,following which each machine will be adapted for use with a particular company's tokens in response to receiving one of those tokens.

Tokens can also be used for collecting data from the device. In this case a further predetermined code is stored in the memory circuit 86, and this is recognised by the microprocessor 58 as an authorisation to transfer into the token 50 the data which is to be collected. This could for example be audit data relating to operations which have been carried out by the machine in which the device is installed.

Once the value ofadebittoken 50 has been redu- ced to zero, the token can, upon payment, have its original value re-inserted into its memory circuit 86.

This can be accomplished using a machinewhich is similar in structure to the interrogation station 32. In this case, however, the microprocessor 58 would be arranged to deliver to the token 50 a further pred etermined value, which for security purposes would be kept secret. This further value would be recognised by the detection circuit 82 and would cause subsequent data to be entered into the memory circuit 86 as the token value. The detection circuit 82 is arranged so that increased token values can only be inserted into the memory circuit 86 when this special code has been received, although of course it will permit decreased values to be entered in other circumstances.

In the arrangement described above, the token 50 is always returned to the user after a transaction ora series of transactions has been carried out. In an alternative embodiment, a gate is providedforselec- tively directing tokens from the interrogation station 32 either to the reject tray or to a storage box. Under normal circumstances the token is returned to the user. However, if the token value decreases to zero, in a debit system, or if the stored account number in a credit token is invalid, the token can instead be retained in the storage box inside the machine.

Interrogation ofthetoken and insertion of data therein is carried out in the above arrangement while the token is held atthe interrogation station 32. Alter- natively, interrogation could take place as the token passes through the coin validator 4. Indeed, interrogation could be carried out using components which are also used for coin validation, e.g. an inductive coil. In this case, the gate 42 can be arranged to be normallyopensothatall itemsotherthanvalid tokens which are rejected by the coin validator 8 are delivered straight to the rejecttray.

Figures 5 and 6 show a preferred structure ofthe token 50. The token is small, and in fact coin-sized and shaped. The token has a lithium battery 100 on which is mounted a printed circuit board 102 via an annular spacer 104. The entire circuit of the token 50, with the exception of the coil 74 and the capacitors 76 and 78, is contained within a single integrated circuit chip 106 mounted on the printed circuit 102. The cap- acitors 76 and 78 may be of the ceramic chip type and are also mounted on the printed circuit board 102.

The coil 74 is formed by a printed circuit etched on the printed circuit board 102. The coil has a spiral configuration, and may contain fr example about ten turns.

The token is encapsulated as indicated at 108 in plastics material. Alternatively, the token could have an openable casing to allow replacement ofthe battery 100.

It will be noted that the token 50 operates correctly irrespective of its specific orientation within the interrogation station 32.

In the above embodiment, the inputcircuit60 produces a two-level output dependent upon the ampli tude of the signal received by the coil 54. This signal is then processed by the microprocessor 58. In an alternative embodiment, the circuit 60 could contain for example a phase locked loop or a monostable circuitfor processing the signal from the coil 54 in order that it may deliver to the microprocessor 58 a digital signal representing the data transmitted by the token 50.

The arrangement described above involves a token which communicates using inductive techniques, and preferably using a transmission frequ encyinthe region of about 10 MHzto 100MHz.

It will of course be appreciated that other techniques could be used without requiring major modification of the circuitry. Low frequency radio techniques could be used, or alternatively optical communication techniques.

Figures Sto 8 illustrate a modified version ofthe circuitry described above in connection with Figures 3 and 4. Although thesewill bedescribed asseparate embodiments, it wi l l of course be appreciated that individual features described in connection with Figures 3 and 4 can be used in the embodiment of Figures 5 to 8, and vice versa. Referring to Figure 5, the token handling device 100 comprises a transmitter drive circuit 102 coupled to a transmitting antenna 104. The token 106 is, in use, disposed between the transmitting antenna 104 and a receiving antenna 108. A receiver circuit 110 is connected to the receiving antenna 108.

A microprocessor 112 has an output line 1 for controlling the transmitter drive circuit 102, three output lines 116 which control the sensitivity of the receiver circuit 110 as will be described, and an input line 118 for receiving data from the receiver circuit 110.The lines 114,116and 118can beconnectedto the microprocessor 112 via appropriate interface circuitry. The microprocessor 112 is also connected to ROM, RAM and non-volatile writable memory circuits 120, 122, and 124, respectively. The non-volatile memory circuit 124 is preferably an EAROM.

The circuitry ofthe token 106 is shown in Figure 7.

The token has an antenna 130 which is connected via a diode 132 to a power storage capacitor 134. The energy transmitted by the antenna 104 is half-wave rectified by the diode 132 and stored by the capacitor 134, the voltage across which is used to powerthe circuitry of the token 106. The received carrier is also delivered to a diode 136 which is used fora.m. demodulation purposes. Interruptions in the transmitted carrier result in pulses at the output of diode 136 which are delivered to a Schmitt inverter 138, the output of which is connected to a latch 140. The latch 140 can be read and cleared by a microprocessor 142 which has ROM, RAM and non-volatile (preferably EAROM) memory circuits 144,146 and 148, respectively.The data is delivered to the micro- processor on line 150 and a clear pulse is delivered to the latch on line 152.

The microprocessor 142 has an additional output line 154 which can control an analog switch 156.

When the switch is turned on, the terminals of the antenna 130 are shorted via a diode 158.

The lines 150,152 and 154would normally be con nected to the microprocessor 142 via appropriate interface circuitry (not shown).

In useofthisembodiment,thetoken handling device is arranged, upon receipt of a token 106, to cause the transmitting antenna 104 to starttransmitting a carrierwave at a frequency of the order of magnitude of100 kHz. Some ofthetransmitted energy will be picked up bytheantenna 130 inthetoken 106and used to power-up the token. Some of the remaining energy will be picked up by the receiving antenna 108.

The transmitter drive circuit 102 is so controlled as to produce interruptions in the carriertransmission.

The interruptions are at regular intervals (say every 1 ms), and each lasts for, say, 3 carrier cycles. They are sufficiently shortthatthe voltage stored across the capacitor 134 in the token 106 does not drop to an extent which would result in interference with the operation of the token circuitry.

The microprocessor 112 in thetoken handling device then adjusts the sensitivity ofthe receiver circuitry 110 using the lines 116 until the microprocessor receives on line 118 clearly defined pulses as shown in Figure 8(a), which correspond to the interruptions in the transmitted carrier.

Adjusting receiving sensitivity in this way should be sufficient to ensure that shorting of the antenna 130 in thetoken 106, which results in a change in the amount of absorbed energy, will result in detectable pulses in the output of the receiving antenna 108. If desired, however, the system could be arranged so that receiver sensitivity is adjusted in response to actual operation of the switch 156 in the token 106 to ensure that the resulting pulses are detectable.

Once the receiver sensitivity has been adjusted, thetoken handling device startsto communicate with the token. To do this, alternate pulses 200 in the carrier wave as shown in Figure 8(a) are used as clock pulses, while the intervening pulses 202 are used as data pulses. The data value of zero is signified by an interruption in the carrier and consequgently a pulse 202, and a data value of 1 is signified by no interruption of the carrier, which will result in a missing pulse 202.

In the token 106, the microprocessor 142 repeat edlychecksfora pulse in the latch 140, and upon detecting the pulse clears the latch. The period between successive pulses is measured and stored.

This measured period allows the microprocessor 142 to calculate a "window" period within which the next pulse is expected.

Data transmissions to the token are always initiated by data value of 1. Accordingly, the microprocessor 142 detects the first time that a pulse does not appear in the latch 140 within the expected period. At that time, the token is able to determine which of the pulses in the succeeding train are clock pulses 200 and which are data pulses 202.

The above description outlines how data istransmitted to the token.

Data stored in the token is transmitted to the token handling device using the analog switch 156. This can be closed for a brief period between the carrier interruptions. These brief closures of the switch 156 will result in extra pulses appearing on the line 118 from the receiver circuit 110 due to the consequent increase in the energy absorbed by the token 106.

The arrangement is such thatwhile the token handling device 100 is expecting to receive data from the token 106, it continuallytransmits data values of zero. The token will have previously received data from the token handling device, and therefore its operation would have been synchronized with the token handling device. Data transmissions from the token are always initiated with a start bit which is transmitted between a clock pulse 200 and a data pulse 202. The start bit is indicated at 204 in Figure 8(b).

Further data is transmitted bit by bit in succeeding intervals between clock pulses 200 and data pulses 202, so that in these intervals an additional pulse 206 may or may not appear depending upon the data content.

In use of the system, for reliability, any data transmission in one direction could be followed bythe same data being transmitted in the opposite direction to ensure a reliable and secure operation.

The token 106 stores in the memory 148 data such as security codes, token value, etc. When the token is first received bythetoken handling device and powered-up bythe received energy, the token and token handling device communicate with each other to check security codes and thus ensure that each is suitable for use with the other. Following this operation, the microprocessor then transmits the token value to the token handling device and at the same time stores in a flag locatiqn ofthe memory 148 an indication thatthis sequence of operations has been completed.

The transmission of the carrier is then terminated, so thatthe token no longer receive power. This is particularly useful in a pay phone installation. At a subsequent stage when further communication with the token is required, the carrier is transmitted once more and the token powers-up. Power-up always results in the microprocessor 142 first checking the flag in the memory 148. In this case, itwill determinethat the preceding operations before power-down were performed to transmitthe credit value to the token handling device. Accordingly, the token will now (after the security code checking operation has been carried out) wait for a new token credit value to be transmitted by the token handling device so that it can update its stored credit value.

At the end of this procedure, the microprocessor 142 resetstheflag in the memory 148 sothatwhen the token is subsequently released to the user and at a latertime inserted again into a token handling device and powered-up it will behave in an appropriate manner to transmitthe token value to the device.

In the above arrangement, it will be noted thatthe data in the token is transmitted by the connecting of a low impedance (the diode 158) across the antenna 130. The diode 158 is used to prevent problems due to back EMF generated in the antenna 130, and also to ensure that the voltage switched bythe analog switch 156 is no greaterthan the supply voltage of that switch. It should be noted though that the alteration of the impedance connected to the antenna 130 could be achieved in some other fashion. In addition, the alteration of the degree of absorption of the electromagnetic radiation could be achieved without affecting the impedance connected to the antenna 130; for example, a separate coil could be used for this purpose.

Figure 6 shows in detail the receiver circuit 110 of the token handling device 100. The receiving coil 108 forms part of a tuned circuit which is coupled via an a.m. demodulating diode 160 to the inverting input of an amplifier 162. The non-inverting input of the amplifier 162 receives a reference potential derived from the junction between, on the one hand, a resistor 164 connected to one powersupply rail, and, on the other hand, a parallel network of resistors 166 connected via respective analog switches 168 to the other power supply rail. The analog switches 168 are controlled by the lines 116 from the microprocessor 112.

The resistors 166 have values R, 2R and 4R. Itwill be appreciated that the reference potentiai delivered tothenon-inverting input of the amplifier 162will vary depending upon which, if any, of the analog switches 168 are closed. This therefore alters re ceiver sensitivity.

Claims (12)

1. A device for communicating with a datastoring token, the device being operable to (a) transmit a carrier signal to the token, (b) transmit data to the token using the carrier signal, and (c) receive data from the token by detecting changes in the degree of absorption of the carrier by the token.

2. A device as claimed in claim 1, wherein the device is operable to transmit power to the token using said carrier signal.

3. A device as claimed in claim 1 or claim 2, wherein the device is operable to transmit clock pulses to the token using said carrier signal.

4. A combination of a token handling device and a data-storing token, the device being operable to transmit to the token clock pulses and data synchronised with the cloche pulses, and the token being operable to transmit data to the device in synchronism with the clock pulses received from the device.

5. A data-storing token arranged to receive power from a device used to read data from the token,thetoken having a non-volatilewritable memoryand being arranged to perform,following power-up, one of a plurality of sequences of operations dependent upon flag data stored in the memory, at least one of those sequences resulting in a change in that flag data.

6. Atoken handling device having means for receiving data transmissions so as to determine data stored by a token, and means for automatically per forming an adjustmentoperationwherebythesen- sitivity of the receiving means is altered in the presence of a token.

7. A device as claimed in claim 6, wherein the device is arranged to transmit a carrier, and the receiving means is operable to detect changes in the absorption of the carrier by the token.

8. A device as claimed in claim 6 or 7, whereinthe device is operable to transmit power to the token.

9. Adevice as claimed in anyone of claims 6to 8, wherein the device is operable to perform said adjustment operation each time it receives a token.

10. Atoken handling device which performs op erationsin accordance with operational data stored in the device, and which is capable of communicating with a token in orderto determine token data stored thereby, the device being operable to enter a first mode or a second mode in dependence upon the type of data, the device being operable in the first mode to perform a said operation and in the second mode to alter the operational data in a mannerdependent upon said token data.

11. A coin validating and token reading device having a common path for receiving coins and tokens and for delivering them to testing apparatus for validating the coins and communicating with the tokens.

12. A device as claimed in claim 11, i ncludi ng val- idating means arranged to receive items from said common path, and to direct non-genuine coins to a reject path and genuine coins to an accept path, and token reading means situated in the reject path.