United States Patent [19]
`Dreifus
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,575,621
`Mar. 11, 1986
`
`[54] PORTABLE ELECTRONIC TRANSACTION
`DEVICE AND SYSTEM THEREFOR
`
`[75]
`
`Inventor: Henry N. Dreifus, Narberth, Pa.
`
`[73] Assignee: Corpra Research, Inc., Rosemont, Pa.
`
`[21] Appl. No.: 586,938
`
`[22]
`
`Filed:
`
`Mar. 7, 1984
`
`[51]
`[52]
`[58]
`
`[56]
`
`Int. Cl,4 ............................................... G06K 5/00
`U.S. Cl ...................................... 235/380; 235/492
`Field of Search ........................ 235/473, 492, 380
`
`References Cited
`U.S. PATENT DOCUMENTS
`3,637,994 1/1972 Ellingboe ......................... 235/61.12
`3, 702,464 11/1972 Castrucci ............................ 340/173
`3,814,841 6/1974 Ulicki .................................. 235/473
`3,868,057 2/1975 Chavez ............................... 235/61.7
`3,876,865 4/1975 Bliss .................................. 235/61.12
`3,906,201 9/1975 Housman ............................ 235/492
`3,906,460 9/1975 Halpern ............................ 340/172.5
`3,934,122 1/1976 Riccitelli ............................ 235/61.7
`3,971,916 7/1976 Moreno ........................... : .. 235/61.7
`4,001,550 1/1977 Schatz ................................ 235/61.7
`4,092,524 5/1978 Moreno ............................... 235/419
`4,102,493 7/1978 Moreno ............................... 235/419
`4,138,058 2/1979 Atalla .................................. 235/473
`4,211,919 7/1980 Ugon ................................... 235/487
`4,277,837 7/1981 Stuctiert .............................. 235/379
`4,341,951 7/1982 Benton ................................ 235/379
`4,405,829 9/1983 Rivest et al. ....................... 178/22.1
`4,423,319 12/1983 Jacobsen ............................. 235/472
`4,454,414 6/1984 Benton ................................ 235/380
`4,460,965 7/1984 Trehn .................................. 235/379
`
`OTHER PUBLICATIONS
`"Memory Cards: A New Concept in Personal Comput-
`
`ing" by Mark Mills, Jan. 1984 issue of BYTE Magazine,
`pp. 154-168.
`"Smart Credit Cards: The Answer to Cashless Shop(cid:173)
`ping" by Stephen B. Weinstein, Feb. 1984 issue ofiEEE
`Spectrum Magazine, pp. 43-49.
`Primary Examiner-Harold I. Pitts
`Attorney, Agent, or Firm-Caesar, Rivise, Bernstein &
`Cohen, Ltd.
`
`ABSTRACT
`[57]
`A portable electronic transaction device and a terminal
`therefor. The device comprises a central data processor,
`a fixed memory, an adaptable memory, optical means
`for transmitting and receiving information to and from
`the terminal and self-contained power source means,
`such as an on-board battery. The device is arranged to
`operate in either a stand-alone mode during which it
`monitors itself for abnormal conditions or in an operat(cid:173)
`ing mode during which it communicates with said ter(cid:173)
`minal for the transmission of information therebetween.
`The device also includes cryptographic means for en(cid:173)
`crypting outgoing information and decrypting incom(cid:173)
`ing information in accordance with cryptographic in(cid:173)
`formation stored in its memory. The cryptographic
`information is modified as a function of time by clock
`means in the device and/or a function of information
`transmitted to the device by the terminal or stored in
`the device. During the standby mode of operation the
`device monitors itself, whereas in its operational mode
`it communicates with the terminal. Power for the
`standy mode is provided, via the on-board battery.
`Power for the operation of the device in the operational
`mode is provided via photocells in the device which are
`arranged to receive light from lamp means in the termi(cid:173)
`nal.
`
`34 Claims, 10 Drawing Figures
`
`8
`
`Page 1 of 18
`
`UNITED SERVICES AUTOMOBILE ASSOCIATION
`Exhibit 1005
`
`

`
`U.S. Patent Mar. 11, 1986
`
`Sheet 1 of6
`
`4,575,621
`
`FIG. I
`
`FIG. 2
`
`Page 2 of 18
`
`

`
`U.S. Patent Mar. 11, 1986
`
`Sheet2 of6
`
`4,575,621
`
`FIG. 3
`
`20
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`FIG 4
`
`Page 3 of 18
`
`

`
`U.S. Patent Mar. 11, 1986
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`Page 5 of 18
`
`

`
`U.S. Patent Mar. 11, 1986
`
`Sheet 5 of6
`
`4,575,621
`
`CENTRAL PROCESSING UNIT
`
`CONTROL
`
`LOGIC
`
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`
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`
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`
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`
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`
`Page 6 of 18
`
`

`
`U.S. Patent Mar. 11, 1986
`
`Sheet 6 of6
`
`4,575,621
`
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`Page 7 of 18
`
`

`
`1
`
`4,575,621
`
`2
`A further security problem with prior art transaction
`devices is that they transmit information between the
`components of the entire system in an unencrypted or
`"clear" form, e.g., standard ASCII symbols, etc. The
`5 transmitted data, e.g., the bit stream, can therefore be
`easily read to determine identifier codes and other inter(cid:173)
`nal security information necessary for access to the
`system. Thus, once identifier codes, communication
`formats, and other system protocols are determined, the
`portable transaction device can be duplicated or forged,
`or the system can be entered at the terminal without a
`valid device.
`Needless to say, the unauthorized or improper use of
`transaction systems can result in the losses of millions, if
`not billions, of dollars and serious breaches in high
`security systems.
`An additional drawback of existing portable transac-
`tion devices is the fact that such devices do not have
`stand-alone capability. That is, they are constructed to
`be inactive (inoperative) when they are not connected
`in the system, e.g., not inserted in the terminal. There-
`fore, attempts at physical intrusion into the devices such
`as by delamination of the material encasing the device
`(e.g., "credit card" type), or inoperative conditions in
`the device as a result of an internal failure cannot be
`detected during the "ofr' or inactive period.
`Examples of prior art transaction devices are shown
`in the following U.S. Pat. Nos. 3,637,994 (Ellingboe),
`3,934,122 (Riccitelli), 3, 702,464 (Castrucci), 3,868,057
`(Chavez), 3,876,865 (Bliss), and 4,001,550 (Schatz) and
`4,211,919 (U gon). The aforegoing devices exhibit one
`or more of the characteristics as described heretofore,
`e.g., the employment of metallic electrical contacts, the
`use of clear (non-encrypted) communication and the
`failure to incorporate any stand-alone capability. U.S.
`Pat. No. 3,906,460 (Halper) discloses a transaction de-
`vice using inductive coupling for communication, yet
`has no stand-alone, encryption or data processing capa(cid:173)
`bilities. The devices disclosed in U.S. Pat. Nos.
`3,971,916 (Moreno), 4,092,526 (Moreno), and 4,102,493
`(Moreno), employ either mechanical or optical cou-
`pling for communications, thereby eliminating the prob(cid:173)
`lems inherent in the use of mechanical electrical
`contact. However, such devices have no stand-alone or
`encryption capability and are hence susceptible to intru(cid:173)
`sion.
`Articles about credit card type transaction devices
`have recently appeared in the following publications:
`Byte magazine, January 1984, pages 154-168, and IEEE
`Spectrum, February 1984, pages 43-49.
`
`PORTABLE ELECfRONIC TRANSACfiON
`DEVICE AND SYSTEM THEREFOR
`
`10
`
`BACKGROUND OF THE INVENTION
`This invention relates generally to electronic transac(cid:173)
`tion systems and, more particularly, to portable elec(cid:173)
`tronic transaction devices and associated terminals
`therefor.
`Recent years have seen the rapid growth in the num(cid:173)
`ber and types of devices carried by the user and em(cid:173)
`ployed for credit card, location access, facility access,
`bank tellering or guard routing purposes. Such devices
`will hereinafter be referred to by the generic term 15
`"transaction devices" to signify the use of these devices
`as a means for effecting a transaction, such as a credit
`card sale, a bank deposit, access authorization, etc.
`Prior art transaction devices have recently made use
`of a card or other compact structure for carrying infor- 20
`mation thereon and which is arranged to be inserted
`into a terminal to transfer information thereto. With the
`advent of micro-chip technology, some transaction
`devices have now incorporated electronic circuitry to
`store, transmit and receive various information such as 25
`identifier information, transaction and status informa(cid:173)
`tion. Thus, the transaction device itself only forms one
`portion of what can be called a transaction system. That
`system can include various independent terminals,
`which may include their own intelligence (via the use of 30
`microcomputers therein) or may be interconnected to a
`remote or host computer (e.g., a main frame computer)
`via telephone lines or other data transmission equip(cid:173)
`ment.
`As is known, the availability and proliferation of 35
`low-cost, powerful microcomputers has resulted in
`increasing numbers of unauthorized intrusions into
`computer-based systems by criminals as well as prank(cid:173)
`sters. Thus, the newly developing transaction devices
`are susceptible to attacks on the security in the systems 40
`using them. For example, existing transaction devices
`frequently make use of mechanical, e.g., metal, contacts
`for connection to the terminal or system. While such
`means are simple in construction and relatively low in
`cost, they offer a readily accessible means for connec- 45
`tion with an intruder's microcomputer to read the infor(cid:173)
`mation in the transaction device or otherwise use it.
`Such action can be readily effected by cycling the mi(cid:173)
`crocomputer through various possible identifier codes
`to gain access to the system and its data. A further 50
`problem with transaction devices employing metal elec(cid:173)
`trical contacts as the means for connection into the
`system is the tendency of such contacts to oxidize or be
`susceptible to physical damage. Either of these occur(cid:173)
`rences can reduce the reliability of electrical continuity 55
`and hence, data transfer.
`Other prior art transaction devices have utilized ca(cid:173)
`pacitance means encapsulated in a card for the storage
`of information therein. Such capacitance-based devices
`are also susceptible to unauthorized access through the 60
`use of various means, such as capacitance bridges. Still
`other electronic transaction systems have made use of
`magnetic strips, such as on conventional plastic credit
`cards, for carrying information. Needless to say, the
`latter type of transaction device offers a very low de- 65
`gree of security inasmuch as the magnetically stored
`data can be readily read and duplicated with existing
`equipment.
`
`OBJECTS OF THE INVENTION
`Accordingly, it is the general object of the instant
`invention to provide a transaction device which over(cid:173)
`comes the disadvantages of the prior art.
`It is a further object of the instant invention to pro(cid:173)
`vide a portable electronic transaction device suitable for
`a wide range of applications.
`It is a further object of the instant invention to pro(cid:173)
`vide a portable electronic transaction device which is
`physically and electrically insulated from the environ(cid:173)
`ment.
`It is a further object of this invention to provide a
`portable electronic transaction device including an en(cid:173)
`cryption/decryption system for communicating with an
`associated system.
`It is still a further object of the instant invention to
`provide a portable electronic transaction device with
`
`Page 8 of 18
`
`

`
`4,575,621
`
`4
`FIG. SC is an enlarged sectional view taken along
`line SC-SC of FIG. SB.
`
`3
`stand-alone monitoring and intrusion detection capabil(cid:173)
`ity.
`It is still a further object of this invention to provide
`a portable electronic transaction device having a capa(cid:173)
`bility to continually or periodically vary encryption and 5
`encoding formats for enhanced security.
`It is still a further object of the instant invention to
`provide a terminal which operates in conjunction with
`and provides a point of entry for an electronic portable
`transaction device.
`It is still a further object of this invention to provide
`a terminal with entry access for two portable electronic
`transaction devices to allow the devices to transmit and
`receive information to and from each other.
`
`10
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`Referring now in greater detail to the various figures
`of the drawing wherein like reference characters refer
`to like parts, there is shown a portable electronic trans(cid:173)
`action device 2 and an associated terminal 20 forming an
`electronic transaction system of the subject invention.
`The details of the portable transaction device and the
`terminal will be described in detail later. Suffice for
`now to state that in the preferred embodiment the porta(cid:173)
`ble transaction device is an electronic device whose
`15 components are encapsulated in a plastic body in the
`form of a flat card, like a conventional plastic credit
`card. Thus, when referring to the device 2 hereinafter,
`the term "card" will be used. It must be pointed out
`however, that the device can take other physical forms
`20 than a card.
`The card 2 includes a programmable data processor,
`a fixed memory to store various information such as,
`part of the operating system program, security informa(cid:173)
`tion in the form of "keys" for a cryptographic system
`25 and identifier information, etc. The card also includes
`an adaptable memory for the storage of transaction
`data, (e.g., financial information, purchase information,
`etc.).
`The card 2 is arranged to operate in either an operat-
`30 ing mode (during which is coacts with a terminal, such
`as terminal 20) or in a stand-alone or standby mode. The
`latter type of operation is that which occurs when the
`card is not connected in the transaction system. It is
`during this mode that the card monitors itself to guard
`35 against intrusion or component failure. Thus, the card 2
`includes a real-time clock and an interrupt control unit
`for effecting various "watchdog" functions when the
`card is in its standby mode.
`The transfer of information between the card and the
`terminal is effected optically. In particular, information
`is transferred from the terminal to the card through the
`use of a light emitting diode(s) in the terminal and
`phototransistor(s) in the card, while the transfer of in(cid:173)
`formation from the card to the terminal is similarly
`effected, via the use of a light-emitting diode(s) in the
`card and a phototransistor(s) in the terminal. Thus, the
`card is arranged to be inserted into a slot in the terminal
`so that the phototransistor(s) of the card is aligned with
`the light-emitting diode(s) in the terminal and with the
`50 light-emitting diode(s) of the card aligned with the
`phototransistor(s) in the terminal so that bi-directional
`communication between the device and the terminal
`can occur.
`As will be appreciated by those skilled in the art, the
`use of the optical means to effect communication be(cid:173)
`tween the card and terminal has the effect of obviating
`the problems inherent in prior art portable electronic
`transaction devices utilizing electrical contacts. More(cid:173)
`over, the encapsulation of the components in the card
`renders them physically, as well as electrically, insu(cid:173)
`lated from the terminal as well as the environment,
`thereby increasing the card's resistance to impairment
`or degradation.
`As stated earlier, the card 2 is arranged to operate in
`65 a stand-alone or standby mode. The power for the card
`when it is in its standby mode is supplied by an on-board
`battery. When in the standby mode, the card monitors
`itself, via its "watchdog" functions, provided by an
`
`45
`
`SUMMARY OF THE INVENTION
`A portable electronic transaction device for use in a
`transaction system having at least one terminal. The
`device is sealed in a container and comprises means for
`storing information therein, means for transmitting and
`receiving information to and from said terminal, inter(cid:173)
`nal, self-contained power source means, means for de(cid:173)
`tecting abnormal conditions in the device and means for
`incapacitating the device in response thereto. The de(cid:173)
`tecting means is powered by the internal power source
`means, whereupon the detecting means is operative at
`all times. When the device is incapacitated it cannot be
`used with the terminal. In accordance with one aspect
`. of the invention, the device includes optical means for
`effecting the transmission and receipt of information to
`and from the terminal and cryptographic means for
`insuring that information transmitted between the de(cid:173)
`vice and the terminal is secure. To that end, the encryp(cid:173)
`tion of information is a function of clock information
`and/or information received from the terminal.
`
`DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a perspective view of a portable electronic
`.transaction device constructed in accordance with the 40
`. instant invention and in the form of an encapsulated flat
`card similar in size and shape to a conventional credit
`card;
`FIG. 2 is a perspective view of a terminal used in
`conjunction with the card of FIG. 1;
`FIG. 3 is an enlarged, exploded perspective view of a
`portion of the terminal's slot and a portion of the card
`shown in FIG. 1;
`FIG. 4 is an enlarged sectional view taken along line
`4-4 of FIG. 3;
`FIG. 5 is a block diagram of the portable electronic
`transaction device and associated terminal of the instant
`invention;
`FIG. 6 is a logic diagram of the interrupt control
`portion of the portable electronic transaction device 55
`shown in FIG. 5;
`FIG. 7 is a block diagram of the central processing
`unit of the portable electronic transaction device;
`FIG. SA is a perspective view of an alternative termi(cid:173)
`nal and two portable electronic transaction devices of 60
`the instant invention for effecting the transfer of infor(cid:173)
`mation from one such device to the other and vice
`versa;
`FIG. SB is an enlarged vertical sectional view taken
`through the terminal of FIG. SA and showing the dis(cid:173)
`position of the two portable electronic transaction de(cid:173)
`vices therein for the transfer of information therebe(cid:173)
`tween; and
`
`Page 9 of 18
`
`

`
`4,575,621
`
`5
`interrupt control circuit therein. The interrupt control
`serves to monitor the card and disable it upon either the
`detection of physical intrusion into the card or the sens(cid:173)
`ing of an inoperative or marginally operative condition
`in the circuitry of the card. Moreover, the interrupt
`control is arranged to switch the card from its standby
`or watchdog function to its active state. In its active
`state power is provided to the card, via the use of photo(cid:173)
`cells in the card. Thus, when the card is inserted in a
`terminal and ready for use, e.g., when a signal is re(cid:173)
`ceived by the card's phototransistor from the terminal
`and light produced by the terminal is received by the
`card's photocells, the interrupt control switches the
`card into the operational mode.
`The card's microprocessor in conjunction with other
`components in the card, e.g., an encryption unit (to be
`described later), serves to encrypt and decrypt informa(cid:173)
`tion which is transmitted to and received from the ter(cid:173)
`minal. The "keys" for effecting the encryption-decryp(cid:173)
`tion process are stored in the card's fixed memory. In
`the interests of increased security the "keys" are ar(cid:173)
`ranged to be modified by the processor as a function of
`the real-time clock data and transaction data stored in
`the adaptable memory. Similarly, user identifier infor(cid:173)
`mation is stored in the fixed memory and may be modi(cid:173)
`fied by the processor as a function of the clock data and
`transaction information stored in the adaptable mem(cid:173)
`ory. External information from the terminal may also be
`placed into the adaptable memory to change the operat(cid:173)
`ing system program, as desired.
`Based on the program(s) within the card's memories,
`the data processor is arranged to calculate and maintain
`user profiles, based upon history of user transactions
`with the card. In such cases, aberrant user conduct can
`be detected by the transaction system and the system 35
`alerted to an unauthorized user in the case of loss or
`theft of the card.
`Moreover, when the transaction system is in a secu(cid:173)
`rity system, such as for providing access to secure facili(cid:173)
`ties, unique individual characteristics such as retinal 40
`patterns, hand geometry or fingerprints, can be stored
`in the card for comparison to information obtained at
`the point of the transaction, e.g., the terminal or entry
`point of the card.
`The data processing and storage capabilities of the 45
`card can be used for sales and marketing purposes as
`well as security. For example, discounts can be given to
`certain types of purchasers based upon the profile and
`data stored in the card. Moreover, credit limits can be
`altered as a function of the past transactions.
`In accordance with a preferred embodiment of the
`transaction system the terminal includes a keyboard for
`use by the terminal operator. The keyboard enables the
`terminal operation to insert various information onto
`the system, e.g., insert user identification codes etc.
`When a card is inserted into the terminal, the card
`transmits encrypted identifier or authentication codes
`and other information to the terminal. The terminal is
`arranged to decrypt the message and identifier informa(cid:173)
`tion. The term.inal then checks for correct corrolation 60
`between the user identifier code and the device's identi(cid:173)
`fier information. The transaction information is dis(cid:173)
`played on a display at the terminal to insure that correct
`keyboard entry is made. Other information, such as
`credit balances, etc., may also be displayed, if desired. 65
`As noted earlier and as will be appreciated by those
`skilled in the art, the transaction· system can be config(cid:173)
`ured for the use intended. Thus, the system can include
`
`6
`a single terminal or a plurality of terminals which can
`communicate with each other or with a remote central
`computer. In the latter case, a modem is included in the
`terminal for effecting communication to the remote
`5 computer. The information flow between the terminal
`and the computer is asynchronous, with the terminal
`providing a temporary buffer storage for outgoing and
`incoming messages. Moreover, if desired, the terminal
`can be constructed to provide a "store and forward"
`10 capability to store messages from cards for a period of
`time and thereafter transmit them to the remote com(cid:173)
`puter at some later time. As is the case with communica(cid:173)
`tions between the card and the terminal, all communica(cid:173)
`tions between the terminal and the remote computer is
`15 in encrypted form.
`Other transaction systems of the subject invention
`may include terminals having sufficient built-in intelli(cid:173)
`gence to operate directly with the card without the
`need for the use of a remote computer. In such a case
`20 the terminal itself is a stand-alone or "smart" terminal.
`With the foregoing summary of the system in mind,
`the details of the card 2 and the terminal 20 will now be
`considered with reference to FIG. 1.
`The card basically comprises an electronic, inte-
`25 grated circuit means 6, light emitting diode means 8,
`phototransistor means 10, battery means 12, photocells
`14, and a liquid crystal display 16.
`The circuit means 6 includes all of the components of
`the card necessary for the functioning of the card and
`30 will be described in detail with reference to FIG. 5. In
`accordance with a preferred embodiment of the inven(cid:173)
`tion circuit means 6 comprises a single VLSI (very large
`scale integrated) circuit chip in the interest of compact
`size.
`The light emitting diode (LED) means 8 can be a
`single light emitting diode or an array of diodes, either
`connected in series, in parallel or in a series-parallel
`arrangement, for producing optical signals to carry
`information from the card to the terminal. The photo(cid:173)
`transistor means 10 can similarly be a single phototran(cid:173)
`sistor or an array of either serial, parallel, or serial-par-
`allel connected phototransistors for receiving optical
`signals from the terminal and for converting them to
`electrical signals for use by the card.
`The liquid crystal display 16 serves to display infor(cid:173)
`mation to the user of the card and the operation of the
`terminal.
`As can be seen in FIG. 1, the card itself is of conven(cid:173)
`tional credit card size and shape, that is approximately
`50 85.5 X 54 X 0.8 mm and thus its body is formed of a plas(cid:173)
`tic or other suitable material, with the components mak(cid:173)
`ing up the operating portions of the device encapsulated
`therein. The plastic material making up the body of the
`card itself or portions of the card's body over the
`55 LED(s) 8, phototransistor(s) 10, photocells 14 and dis(cid:173)
`play 16 is preferably either translucent or transparent.
`Such a material is preferred so that the information may
`be transmitted and received by the light emitting diodes
`and phototransistors, power may be received by the
`photocells and the display 16 be readily visible, all with(cid:173)
`out optical impediment.
`The remainder of the body of the card may contain
`the features normally found on conventional credit or
`user access cards, such as embossed numbers and letters,
`an encapsulated photograph of the user, etc.
`Referring now to FIG. 2, the details of an exemplary
`terminal 20 is shown. As can be seen, terminal 20 basi(cid:173)
`cally comprises a display 22, a set of controls 24 and a
`
`Page 10 of 18
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`4,575,621
`
`7
`keyboard 26. The controls 24 provide for power and
`housekeeping functions, such as power on-off switches
`and indicator lamps. The keyboard can be any type,
`alpha/numeric, or numeric, and is used by the terminal
`operator to insert transaction information and an identi- 5
`fier code into the system.
`Terminal 20 includes a slot 28 into which the card is
`inserted to perform a transaction and effect the transfer
`of information between the terminal and card and vice
`versa. Thus, in the embodiment shown herein the card 10
`wiii be described as a retail purchase credit card, and
`the terminal as a point-of-sale terminal. One "transac(cid:173)
`tion" in such an application entails the sale of one or
`several items. As each item is "rung up" by the terminal
`operator, that is entered into the keyboard, the display 15
`22 shows the identity of each item purchased and its
`price. This serves as a check of keyboard entry accu(cid:173)
`racy. The credit balance available to the user of the card
`2 wiii be transmitted to the terminal during data transfer
`therebetween and may be displayed on the terminal 20
`display. Such information is based on information re(cid:173)
`ceived by the terminal either from a remote computer,
`if the terminal is connected thereto, or from the infor(cid:173)
`mation provided by the card itself.
`If the card is used in another application than the 25
`retail point-of-sale application just described, the trans(cid:173)
`action would obviously have a different format. For
`example, when the card 2 is used as a guard route
`checking device, the "transaction" entails the detection
`and recording of the use of the card at a prescribed 30
`· location along the guards route. The data and time of
`· use of the card is also detected and recorded.
`Referring now to FIG. 3 the details of the card re(cid:173)
`ceiving slot 28 of the terminal will now be described.
`Thus, as can be seen the upper wall 30 of the slot 28 35
`includes a source of light 32, electronic integrated cir-
`:·cuit means 38, phototransistor means 36 and light emit(cid:173)
`:.:ting diode means 34 all mounted therein. Those compo(cid:173)
`··"nents are so located so that when the card is fully in(cid:173)
`'Serted in the slot 28 and its leading edge 40 makes 40
`contact with the slot's rear wall 42, the card's photo(cid:173)
`transistor(s) 10 is located directly beneath the LED(s)
`of the terminal 20 so that the optical signals transmitted
`from the LED(s) are received by the phototransistor(s)
`for conversion into electrical signals for use by the 45
`card's circuitry. Similarly, LED(s) 8 of the card 2 is
`located directly beneath the phototransistor(s) of the
`terminal 20 so that the optical signal transmitted by the
`LED(s) are received by the phototransistor(s) for con(cid:173)
`version into electrical signals for use by the terminal's 50
`circuitry.
`Any commercially available light emitting diodes and
`phototransistors operating in either the infrared spec(cid:173)
`trum or visible light spectmm are suitable for use in the
`subject system. The light source 32 for powering the 55
`card in its operational mode can be any conventional
`lamp and is located in the slot position directly over the
`card's photocells. The photocells convert the light re(cid:173)
`ceived into electrical power for the card.
`As can be seen the card's displaY. means 16 is located 60
`on the card at a slightly inboard portion adjacent the
`end of the card so that it is fully visible when the card
`is inserted into the slot. This feature enables the user or
`terminal operator to read the card when it is in the
`terminal.
`As can also be seen in FIG. 3 each side of the slot 28
`includes a ledge 44. The ledges serve to properly posi(cid:173)
`tion the card within the slot. In this connection the
`
`8
`depth of each ledge is selected to insure proper distance
`between the light emitting diode(s) and phototransis(cid:173)
`tor(s) of the card and terminal for proper signal trans-
`mission and reception and for proper distance between
`the light source 32 and the photocells for efficient
`power transmission. In particular, spacing of approxi- ·
`mately 1 em between the top surface 46 of the card 4
`and the top wall 30 of the slot is desirable.
`The circuitry of the terminal 20 will be described in
`detail later. Suffice for now to say that it includes the
`integrated circuit means 38 mentioned heretofore. This
`circuit means effects data processing by the terminal
`and in addition includes logic and interfacing circuitry
`(to be described later), to allow for the operation of the
`display 22, controls 24 and keyboard 26.
`In FIG. 5 the block diagram of the components mak(cid:173)
`ing up the card 2 and the terminal 20 are shown. In that
`diagram the flow of signal information is depicted by
`solid lines, while the flow of power is denoted by bro(cid:173)
`ken lines. As can be seen the integrated circuit 6 basi(cid:173)
`cally comprises central processing unit (CPU) 52, a high
`speed crystal oscillator or clock 54, a read only memory
`(ROM) 56, a random access memory (RAM) 58, direct
`memory access (DMA) circuitry 60, an interrupt con(cid:173)
`trol unit circuit 62, a communications buffer 64, and a
`ti