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Contents
1. and received codes are identical until said external power is removed from said microcomputer 93 The security system as defined by claim 81 wherein said comparator means selectively produces said first output signal responsive to user actions upon determining that said first predetermined and received codes are identical until said external power is removed from said microcomputer 94 The security system as defined by claim 81 wherein said second predetermined code is used for a security related function 95 The security system as defined by claim 81 wherein said first and second predetermined codes are different from each other 96 The security system as defined by claim 81 wherein said microcomputer is programmed to use said first and second predetermined codes for different functions 97 The security system as defined by claim 96 wherein said first and second predetermined codes are used for different security related functions 98 The security system as defined by claim 7 wherein said microcomputer causes an encrypted version of said first B1 4 604 708 9 predetermined code to be displayed responsive to said received code matching said second predetermined code 99 The security system as defined by claim 8 wherein said first output signal comprises a control signal selectively produced by said microcomputer to control the operation of said protected device upon determining that said first pre determined and received codes2. are identical and wherein said coupling means comprises a signal path coupling said control signal from said microcomputer to said protected device 100 The security system as defined by claim 81 wherein said comparator means compares a first alphanumeric char acter of said received code with a first alphanumeric char acter of said first predetermined code and in the absence of a match compares said first received alphanumeric charac ter with a first alphanumeric character of said second predetermined code 101 The security system as defined by claim 81 further including display means coupled to said comparator means for displaying alphnumeric characters 102 The security system as defined by claim 81 wherein an encrypted version of said first predetermined code is displayed if said received code matches said second prede termined code 103 The security system as defined by claim 81 wherein said storage means includes an alarm routine stored as a predetermined sequence of binary quantities and said microcomputer means execuies said alarm routine in the absence of a match between said received code and said first and second predetermined codes stored within said storage means 104 The security system as defined by claim 81 wherein said electronic system includes a main power switch and wherein said microcomputer is coupled to said external power source upstream from the coupling of said main power switch to said external power
3. code system which re quires the user to input a predetermined code in order to gain access to or enable the protected device Thus each time a user desires to operate a device incorporat ing a security code system he must input the predeter mined code An example of an electronic system for a solid state device is disclosed in U S Pat No 4 139 864 by Schul man The Schulman security circuit is in part formed on one of the same micro electronic chips as that of the electronic device itself thereby preventing a thief from physically bypassing the circuit In order to enable the device a user must key in a pass code which when compared and matched with a preset internal code allows access to the device An example of an electronic security system for the control of communication signals is disclosed by Laun zel U S Pat No 4 179 733 The Launzel circuit incor porates a microprocessor which executes a predeter mined sequence of operations upon the activation of the device s power switch Once a predetermined security code has been entered by the user the circuit compares the inputted code with a code stored in memory and if a match occurs the communication system is enabled Systems such as Schulman and Launzel require that the user enter the pass code each time he desires to make use of the device For devices such as televisions stereo receivers microwave ovens and other related items which are frequently used sporadica
4. for electronic devices which is both secure and convenient for the user As will be disclosed below the present invention overcomes the disadvantages associated with pass code systems such as Schulman Launzel and other prior art systems by providing a unique security circuit which requires that a security code be entered only once in order to enable a device as long as a continuous source of power is supplied thereto SUMMARY OF THE INVENTION The present invention is most advantageously used in conjunction with televisions radio receivers and other electrical devices which require an external power source A microcomputer executes a power on routine stored in memory each time the device is coupled to the power source The user must enter a primary security code which is compared with a stored or algorithmi cally generated code and if the codes match the device is enabled Once enabled the device may be operated without reentering the security code as if the security system were not present until the power source is re moved by for example a thief unplugging the device from an A C line If an incorrect security code is entered the mi crocomputer executes an alarm routine which may display HOT or the like on a digital readout and may energize an audible alarm signal If the primary security code is misplaced by a user the manufacturer or its authorized agent after satisfacto rily identifying the user provides a sec
5. pling of said microcomputer to said extemal power source so that said microcomputer remains connected to said external power source independently of whether said relay means is coupling said external power source to said protected device whereby said received code need only be reentered if the coupling of said microcomputer to said external power source is interrupted 9 A security system including a microcomputer for protecting an electrically powered protected device corre sponding to all or a portion of an electronic system such that once said protected device has been enabled it will remain capable of being operated unless the security device system is disconnected from an external power source comprising a microcomputer connected to said external power source and receiving power from said external power source unless said security system is disconnected from the external power source storage means connected to said microcomputer for stor ing first and second predetermined codes input means connected to said micorcomputer micro computer for receiving a code comparator means included in the microcomputer said comparator means being coupled to said storage means and said input means for comparing said first pre determined code with said received code and for pro ducing a first output signal upon determining that said first predetermined and received codes are identical coupling means connected to receive said fi
6. previously known in the art the present invention does not require a user to enter the security code each time the device is to be operated Rather the security code need only be entered when power is initially applied to the device by plugging it into an A C socket or by coupling it to a D C power 4 604 708 7 source such as an automotive electrical system The use of a secondary code to provide an encrypted version of the primary security code and a decryption algorithm to recover the true primary code helps prevent abuses by personnel who are employed by the manufacturer in that the primary code may be available only on a need to know basis In addition the present invention is rela tively inexpensive and may be realized with little modi fication to devices already incorporating a microcom puter control system such as for example a frequency synthesized tuning circuit Thus a security system for electronic devices has been described which is both highly secure and conve nient for the user I claim 1 A security system including a microcomputer for protecting an externally powered device such that once said device has been enabled it will remain capable of being operated unless the security system is discon nected from the external power source comprising a microcomputer connected to said external power source storage means for storing a predetermined code input means for receiving a code comparator means c
7. said comparator means compares each of a plurality of entries of said received code with a corresponding portion of said stored predetermined codes as each of said entries are entered through said input means 51 The security system as defined by claim 46 wherein said storage means comprises a semiconductor program mable read only memory integrated circuit 52 The security system as defined by claim 46 wherein said electronic system includes a main power switch and wherein said microcomputer is coupled to said external power source upstream from the coupling of said main power switch to said extemal power source so that said microcomputer remains connected to said external power source independently of whether said main power switch is on or off 53 The security means as defined by claim 46 wherein said microcomputer executes a power up routine responsive to said external power source being initially applied to said microcomputer and wherein said power up routine causes said comparator means to compare said predetermined code with said received code 10 15 25 35 40 45 55 65 6 54 The security system as defined by claim 46 wherein said external power source comprises an AC power source 55 The security system as defined by claim 46 wherein said comparator means produces said first output signal immediately upon determining that said predetermined and received codes are identical 56 The security system as de
8. said external power source upstream from the coupling of said main power switch to said external power source so that said microcomputer remains connected to said external power source independently of whether said main power is on or of
9. source so that said microcomputer remains connected to said external power source independently of whether said main power switch is on or off 105 A security system for protecting an electrically powered protected device corresponding to all or a portion of an electronic system such that once said device has been enabled it will remain capable of being operated unless the security system ts disconnected from an external power source comprising a microcomputer connected to said external power source and receiving power from said external power source unless said electronic system is disconnected from the external power source storage means connected to said microcomputer for stor ing first and second predetermined codes input means connected to said microcomputer for receiv ing a code comparator means included in the microcomputer said comparator means being coupled to said storage means and said input means for comparing said first predetermined code with said received code and for producing a first output signal upon determining that said first predetermined and received codes are identical said first output signal being a control signal selectively produced by said microcomputer to control the operation of said protected device and coupling means connected to receive said first output signal for enabling said protected device upon receipt of said first output signal said coupling means includ ing a signal path coupling sai
10. the application of power to the power supply 12 executes a power on routine which is stored in ROM 32 The power on routine as will be described requires the microcomputer to await the input of a code from keypad 24 As the user inputs a code microcomputer 10 compares the keyed in security code keystroke by keystroke with a predetermined primary security code stored in PROM 34 If the codes match microcomputer 10 signals the relay driver 18 on line 36 to provide A C power to the device by activat ing the main power relay 22 Power is thereby provided to the device s main power supply 37 or other applica ble circuit depending on the nature of the device pro tected Additionally once the proper code is entered microcomputer 10 issues other control and enable sig nals as may be required by the particular device which is protected such as by way of illustration frequency selection timer volume and contrast control signals With reference to FIG 2 the power on sequence of operations of the microcomputer 10 is described In the diagrams there shown diamond shaped boxes with or marks represent decision points in the program If the condition received by the decision is satisfied at the time ma 0 25 30 50 60 4 it is encountered then the next operation is the one determined by following the line marked by a Y If the condition is not satisfied the next instruction is determined by following the line mark
11. wherein said microcomputer is coupled to said external power source upstream from the coupling of said main power switch to said external power source so that said microcomputer remains connected to said external power source independently of whether said main power switch is on or off 23 The security system as defined by claim wherein said microcomputer executes a power up routine responsive to said external power source being initially applied to said microcomputer and wherein said power up routine causes said comparator means to compare said first predetermined code with said received code 24 The security system as defined by claim wherein said external power source comprises an AC power source 25 The security system as defined by claim wherein said comparator means produces said first output signal imme diately upon determining that said first predetermined and received codes are identical 26 The security system as defined by claim 1 wherein said input means comprises a keypad 27 The security system as defined by claim wherein said microcomputer further controls the operation of at least a portion of said electronic system other than said security system 28 The security system as defined by claim 1 wherein said relay means comprise a relay coupled to said comparator means said relay coupling said external power source to said protected device responsive to receiving said first output signal from said comparator mea
12. D DEVICES This application is a continuation of application Ser No 328 080 filed Dec 7 1981 now abandoned BACKGROUND OF THE INVENTION 1 Field of the Invention The invention relates to electronic security systems particulary those systems which require a predeter mined code to be entered by a user in order to gain access to or enable a device 2 Prior Art The escalating crime rate in recent years has prompted a need for increased security measures to protect personal property A frequent target of thieves is electronic devices such as for example televisions radios microwave ovens calculators and stereophonic systems Due to the portability of many of these modern electronic devices a thief can with relative ease resell or fence the stolen device after altering or destroying the manufacturer s serial number thus rendering trac ing by law enforcement agencies difficult if not impossi ble Attempts to secure electronic devices were initially directed toward mechanical means which physically lock or disable the television calculator or the like However mechanical means have inherent disadvan tages which serverely limit the practicality of this type of solution For example the mechanical means are typically expensive and additionally eliminate or re strict portability which is a major advantage of modern electronic devices Electronic solutions to the problem of theft have included the use of a security
13. TION PATENT NO 4 604 708 DATED August 5 1986 INVENTOR S Lewis It is certified that error appears in the above identified patent and that said Letters Patent is hereby corrected as shown below COLUMN LINE DESCRIPTION 8 46 Between the words only and reentered delete a and insert be Signed and Sealed this Twenty first Day of April 1987 Attest DONALD J QUIGG Attesting Officer Commissioner of Patents and Trademarks ECEE O COR TE KDA CON TE DOD R AOO OTT US004604708B1 REEXAMINATION CERTIFICATE 3351st United States Patent 19 Lewis uu B1 4 604 708 45 Certificate Issued Oct 14 1997 54 ELECTRONIC SECURITY SYSTEM FOR EXTERNALLY POWERED DEVICES 76 Inventor Gainer R Lewis 7018 Pacific View Dr Hollywood Calif 90068 Reexamination Request No 90 004 150 Feb 23 1996 Reexamination Certificate for Patent No 4 604 708 Issued Aug 5 1986 Appl No 669 727 Filed Nov 8 1984 Related U S Application Data 63 Continuation of Ser No 328 080 Dec 7 1981 abandoned 51 Int CL Ul msson GOGF 13 00 GOGE 7 04 52 U S CI umamnannanaso mo 395 188 01 340 825 31 58 Field of Search u s 395 186 187 01 395 188 01 364 918 7 307 10 7 10 6 10 5 10 4 10 3 10 2 380 3 4 23 455 346 345 347 56 References Cited U S PATENT DOCUMENTS 3 796 889 3 1974 Fradkin et al 0 ccccsssccsscese 317 134 3 987 408 10 1976 Sassover et
14. United States Patent n9 Lewis 54 76 21 22 63 51 52 58 56 ELECTRONIC SECURITY SYSTEM FOR EXTERNALLY POWERED DEVICES Inventor Gainer R Lewis 7018 Pacific View Dr Hollywood Calif 90068 Appl No 669 727 Filed Nov 8 1984 Related U S Application Data Continuation of Ser No 328 080 Dec 7 1981 aban doned Tit C14 iina G08B 13 06 GO6F 1 00 B60R 25 00 LOPE PANATA 364 900 340 825 31 Field of Search 340 825 3 825 31 825 32 340 825 34 364 200 900 References Cited U S PATENT DOCUMENTS 4 103 289 7 1978 Kolber oo seen 340 825 32 4 179 733 12 1979 Launzel et al woe 364 200 4 288 659 9 1981 Atalla 340 825 31 4 310 720 1 1982 Check Jr neeese 364 900 4 333 074 6 1982 Sutherland et al 340 825 3 4 333 090 6 1982 Hirsch eee 340 825 3 4 366 466 12 1982 Lutz oo so 340 825 31 4 447 890 5 1984 Duwiel et al oo 364 900 11 Patent Number 4 604 708 45 Date of Patent Aug 5 1986 OTHER PUBLICATIONS Byte Word Protection for Your Computer by R Jordan Kreindler Mar 1979 pp 194 195 Primary Examiner Gareth D Shaw Assistant Examiner Daniel K Dorsey Attorney Agent or Firm Blakely Sokoloff Taylor amp Zafman 57 ABSTRACT An electronic security system for a device requiring an external power source is disclosed The security system includes a microcomputer which executes a power on routine stored in memory w
15. al e 340 53 4 002 956 1 1977 Minor et al 340 280 4 103 289 7 1978 Kolber ou eeccsssccsssesseccees 340 164 4 179 733 12 1979 Launzel et al 364 200 4 267 578 5 1981 Vetter 4 288 659 9 1981 Atalla enesesenoressssounnossosseas 178 22 08 4 288 778 9 1981 Zucker me 340 64 4 308 536 12 1981 Sims Jr et al wo csssssscecesesneee 34317 4 310 720 1 1982 Check Jr u 178 22 08 4 333 074 6 1982 Sutherland et al m ee 340 825 3 4 449 385 5 1984 Thirion et al 0 2 ssssscsseseeeeese 70 277 FOREIGN PATENT DOCUMENTS 49 29527 3 1974 Japan 56 42436 4 1981 Japan OTHER PUBLICATIONS Reference Data for Radio Engineers Sams and Co ITT pp 40 19 Webster s New World Dictionary of Computer Terms Pren tice Hall pp 234 235 1965 MCS 4 Microcomputer Set Users Manual Rev 5 Intel Corp p 4 1974 MCS 80 User Manual Intel Corp pp O 1977 Introduction to Microprocessors Software Hardware Pro gramming L Leventhal Printice Hall pp 19 435 1978 The art of electronics Horowitz and Hill CambridgeUni versity Press pp 453 and 484 1980 Primary Examiner Robert W Beausoliel Jr 57 ABSTRACT An electronic security system for a device requiring an external power source is disclosed The security system includes a microcomputer which executes a power on rou tine stored in memory whenever the microcomputer is initially coupled to a power source Th
16. an alarm mode and displays HOT or some other similar message in the digital display 26 and does not enable the main power relay 22 through the relay driver 18 Thus until power is re moved by for example removing the A C plug the microcomputer will not permit further keyboard entries and will not enable power to be coupled to the pro tected device through the main power relay 22 As illustrated in FIG 2 the alarm mode may include an 4 604 708 5 optional audible alarm tone in the form of a warble generated by the microcomputer as a digital pulse train of varying period and incorporate a flashing digital display As depicted if the first inputted digit matches with either the stored primary or secondary code any subsequent digit which when compared fails to match will automatically send the microcomputer into the alarm mode If all of the digits or characters comprising the pri mary security code are properly entered then mi crocomputer 10 signals relay driver 18 on line 36 to activate the main power relay 22 thereby providing power to the protected device In addition microcom puter 10 after a proper code has been fully entered performs all other functions as may be required by the particular device for example tuning channel selection and other similar functions Assume for the sake of example that a user plugs a device protected by the present invention into an A C outlet Microcomputer 10 executes the above des
17. be any one of a variety of types currently commercially available It will be appreciated from the discussion which follows that an existing on board microcomputer of the type typically used in frequency synthesized tuning systems in television and radio may be utilized with little modi fication to those devices which incorporate such tuning systems The microcomputer 10 receives D C power from a D C logic power supply 12 which in the presently preferred embodiment is coupled to an A C external power source 14 by line 16 The logic power supply 12 is also coupled to a relay driver 18 by line 20 which as will be discussed controls the operation of the main power relay 22 which in turn controls the availability of power to the protected device The microcomputer 10 is coupled to a keypad 24 by line 25 and to a digital display 26 by line 28 In addition microcomputer 10 is coupled to a read only memory ROM 32 and to a programable read only memory PROM 34 As will be discussed more fully below the ROM 32 contains a power on sequence of operations which the microcomputer performs whenever external A C power is initially supplied on line 16 In operation a device incorporating the present in vention is supplied with external power typically by coupling line 16 to a household A C outlet The logic power supply 12 converts the A C current into a D C source and provides the requisite D C current on line 17 Microcomputer 10 upon
18. claim 10 wherein an encrypted version of said first predeter mined code is displayed if said received code matches said second predetermined code 12 The security system as defined by claim 11 wherein said comparator means compares a first alpha numeric character of said received code with a first alphanumeric character of said first predetermined code and in the absence of a match compares said first re ceived alphanumeric character with a first alphanu meric character of said second predetermined code 13 The security system as defined by claim 12 wherein said comparator means comprises microcom puter means capable of executing stored sequences of binary quantities 14 The security system as defined by claim 13 wherein 4 604 708 9 said storage means includes an alarm routine stored as a predetermined sequence of binary quantities said microcomputer means executes said alarm rou tine in the absence of a match between said re ceived code and said first and second predeter mined codes stored within said storage means 15 The security system as defined by claim 14 10 20 25 30 35 45 50 55 65 10 wherein said relay means comprises an electrical relay driven by a relay driver coupled to said microcomputer means 16 The security system as defined by claim 15 wherein said input means comprises a keypad UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORREC
19. claim 9 wherein said coupling means enables said protected device by selectively coupling power to said protected device upon receipt of said first output signal 63 The security system as defined by claim 9 wherein said protected device comprises an applicable circuit component of said electronic system 64 The security system as defined by claim 9 wherein said comparator means compares each of a plurality of entries of said received code with a corresponding portion of said first predetermined code as each of said entries are entered through said input means 65 The security system as defined by claim 9 wherein said storage means comprises a semiconductor programmable read only memory integrated circuit 66 The security system as defined by claim 9 wherein said second predetermined code compries a plurality of charac ters 67 The security system as defined by claim 9 wherein said microcomputer executes a power up routine responsive to said external power source being initially applied to said microcomputer and wherein said power up routine causes said comparator means to compare said first predetermined code with said received code 68 The security system as defined by claim 9 wherein said external power source comprises an AC power source 69 The security system as defined by claim 9 wherein said comparator means produces said first output signal imme diately upon determining that said first predetermined and received codes a
20. conductor program mable read only memory integrated circuit 37 The security system as defined by claim 31 wherein said electronic system includes a main power switch and wherein said microcomputer is coupled to said external power source upstream from the coupling of said main power switch to said external power souce so that said microcomputer remains connected to said external power source independently of whether said main power switch is on or off 38 The security system as defined by claim 31 wherein said microcomputer executes a power up routine responsive to said external power source being initially applied to said microcomputer and wherein said power up routine causes said comparator means to compare said stored predeter mined code with said received code 39 The security system as defined by claim 31 wherein said external power source comprises an AC power source 40 The security system as defined by claim 31 wherein said comparator means produces said first output signal immediately upon determining that said predetermined and received codes are identical 41 The security system as defined by claim 31 wherein said input means comprises a keypad 42 The security system as defined by claim 31 wherein said microcomputer further controls the operation of at least a portion of said electronic system other than said security system 43 The security system as defined by claim 31 wherein said relay means comprises a relay cou
21. cribed power on routine and awaits the input of the primary security code After the user has inputted the code microcomputer 10 enables the protected device by sig naling the relay driver 18 to provide power to the de vice s other systems Once the proper code has been entered a subsequent user need not reenter the code in order to operate the device at a later time Rather the user may operate the device as if the security system was not installed in the device For example in the case of a radio or television the user would merely switch the device into the on position and operate it in a normal manner However if the protected device is unplugged as would be the case where a thief has re moved it or if the power fails then entry of the primary code would be required prior to subsequent use since once power has returned microcomputer 10 automati cally executes the above described power on routine Assume further that the registered owner of the pro tected device has misplaced or has forgotten the pri mary security code The owner contacts the manufac turer of the device or authorized representative and after supplying proper identification such as for exam ple name address serial number and or date and place of purchase the manufacturer or its representative supplies the owner with the above described secondary security code The owner plugs the device into an A C outlet and enters the secondary code on keypad 24 A
22. d by claim 77 wherein said microcomputer causes an encrypted version of said first predetermined code to be displayed responsive to said received code matching said second predetermined code 79 The security system as defined by claim 9 wherein said Jirst output signal comprises a control signal selectively produced by said microcomputer to control the operation of said protected device upon determining that said first pre determined and received codes are identical and wherein said coupling means comprises a signal path coupling said control signal from said microcomputer to said protected device 80 The security system as defined by claim 9 wherein said electronic system includes a main power switch and wherein said microcomputer is coupled to said external power source upstream from the coupling of said main power switch to said external power source so that said microcomputer remains connected to said external power source independently of whether said main power switch is on or off 81 A security system for protecting an electrically powered protected device corresponding to all or a portion of an electronic system such that once said device has been enabled it will remain capable of being operated unless the security system is disconnected from an external power source said security system comprising a microcomputer connected to said external power source and receiving power from said external power source unless said electronic
23. d control si gnal from said microcomputer to said protected device 5 10 15 20 35 40 first predetermined and received codes are 45 55 65 10 whereby said received code need only be reentered if the connection of said microcomputer to said external power source is interrupted 106 The security system as defined by claim 105 wherein said comparator means compares said first predetermined code with said received code responsive to said external power being applied to said microcomputer 107 The security system as defined by claim 105 wherein said protected device comprises an applicable circuit com ponent of said electronic system 108 The security system as defined by claim 105 wherein said comparator means compares each of a plurality of entries of said received code with a corresponding portion of said first predetermined code as each of said entries are entered through said input means 109 The security system as defined by claim 105 wherein said storage means comprises a semiconductor program mable read only memory integrated circuit 110 The security system as defined by claim 105 wherein said second predetermined code comprises a plurality of characters 111 The security system as defined by claim 105 wherein said external power source comprises an AC power source 112 The security system as defined by claim 105 wherein said comparator means produces said first output signal immediately upon deter
24. e microcomputer 10 com pares the first inputted digit with a secondary code also stored in PROM 34 As will be discussed this second ary code provides additional security to the device since it can only be obtained from the manufacturer or its authorized agents If the first inputted digit matches the first digit of the secondary code then subsequent digit entries by the user are compared only with the stored secondary code Thus it will be noted that in the presently preferred embodiment the primary and sec ondary codes may not incorporate identical first digits in order to avoid ambiguity as to which code mi crocomputer 10 is to compare However if identical first digits are desired the power up routine can be easily modified such that other digits or the like are compared to identify which code is being entered As shown in the flow diagram of FIG 2 upon the proper entry of all digits of the secondary code microcom puter 10 displays an encrypted version of the primary security code on digital display 26 It will be appreci ated that the encrypted version of the primary security code may be either stored in a memory location within the PROM 34 or may be generated by an encryption algorithm stored within ROM 32 and executed by the microcomputer As shown in FIG 2 if the first digit or character entered by the user does not match either the primary security code or the secondary code as discussed above the microcomputer enters
25. e user must enter a primary security code which is compared to a predetermined code and if the codes match the microcomputer signals a relay to provide power to the device thereby enabling it Once enabled the user need not reenter the security code as long as the external source of power to the device remains uninterrupted A secondary security code may be entered if the primary code has been forgotten or misplaced Upon entry of the secondary code the microcomputer displays an encrypted version of the primary security code If an incor tect code is entered by the user the microprocessor executes an alarm routine which may include visual and audible warnings fa Cournot amp Lvaakt EAMES B1 4 604 708 1 REEXAMINATION CERTIFICATE ISSUED UNDER 35 U S C 307 THE PATENT IS HEREBY AMENDED AS INDICATED BELOW Matter enclosed in heavy brackets appeared in the patent but has been deleted and is no longer a part of the patent matter printed in italics indicates additions made to the patent AS A RESULT OF REEXAMINATION IT HAS BEEN DETERMINED THAT Claims 1 2 9 15 are determined to be patentable as amended Claims 3 8 10 14 16 dependent on an amended claim are determined to be patentable New claims 17 126 are added and determined to be patentable 1 A security system including a microcomputer for protecting an externally powered protected device corre sponding to all or a portion of an electronic sy
26. ed N Rectan gular symbols represent operations which are carried out by he microcomputer and its associated elements An oval symbol represents a starting entry into the program sequence by virtue of the initial application of power to the microcomputer from logic power supply 12 once the device to be protected is plugged in The sequence of operations follows the path defined by the arrows The program is delineated by following the lines joining the various symbols FIG 2 indicates the sequence of steps executed when power is first applied by plugging the protected device into an A C power source The program begins at the oval marked Enter on Power up The microcom puter initially executes a getkey operation in which it scans the keypad 24 and awaits the input of the first digit or character of the primary security code Upon entry of a first digit by the user microcomputer 10 compares the entered digit with the first digit of the predetermined primary security code stored in PROM 34 As is illustrated in FIG 2 if a match exists the mi crocomputer executes another getkey operation and compares the second inputed digit or character to the second digit of the stored primary security code Mi crocomputer 10 continues this input and compare se quence until all of the digits of the security code are thereby entered and compared If the inputted first digit does not match the first digit of the stored primary cod
27. ernal power source 10 15 20 25 35 45 50 55 60 65 4 storage means for storing a predetermined code input means for receiving a code and comparator means included in the microcomputer said comparator means being coupled to said storage means and said input means for comparing said pre determined code with said received code and for pro ducing said first output signal upon determining that said predetermined and received codes are identical whereby said received code need only be reentered if the coupling of said microcomputer to said external power source is interrupted 32 The security system as defined by claim 31 wherein said comparator means compares said predetermined code with said received code responsive to said external power source being applied to said microcomputer 33 The security system as defined by claim 31 wherein said protected device comprises the main power supply of said electronic system 34 The security system as defind by claim 31 wherein said protected device comprises an applicable circuit component of said electronic system 35 The security system as defind by claim 31 wherein said comparator means compares each of a plurality of entries of said received code with a corresponding portion of said stored predetermined code as each of said entries are entered through said input means 36 The security system as defined by claim 31 wherein said storage means comprises a semi
28. evice and connected to be actuated by said first output signal such that external power is provided to the protected device by coupling said external power source to said device upon receipt of said first output signal whereby said received code need only be reentered if the coupling of said microcomputer to said external power source is interrupted 3 The security system as defined by claim 2 wherein said comparator means compares a first alphanumeric character of said received code with a first alphanu 15 20 30 50 60 65 8 meric character of said first predetermined code and in the absence of a match compares said first received alphanumeric character with a first alphanumeric char acter of said second predetermined code 4 The security system as defined by claim 3 further including display means coupled to said comparator means for displaying alphanumeric characters 5 The security system as defined by claim 4 wherein an encrypted version of said first predetermined code is displayed if said received code matches said second predetermined code 6 The security system as defined by claim 5 wherein said comparator means comprises microcomputer means capable of executing stored sequences of binary quantities 7 The security system as defined by claim 6 wherein said storage means includes an alarm routine stored as a predetermined sequence of binary quantities said microcomputer means executes said alarm
29. fined by claim 46 wherein said input means comprises a keypad 57 The security system as defined by claim 46 wherein said microcomputer further controls the operation ofat least a portion of said electronic system other than said security system 58 The security system as defined by claim 46 wherein said relay means comprises a relay coupled to said com parator means said relay coupled said external power source to said protected device responsive to receiving said first output signal from said comparator means 59 The security system as defined by claim 46 wherein said relay means comprises a relay driver coupled to said comparator means said relay driver receiving said first output signal and generating a relay drive signal responsive thereto and a relay coupled to said relay driver said relay coupling said external power source to said protected device responsive to receiving said relay drive signal from said relay driver 60 The security system as define by claim 46 wherein said comparator means continuously produces said first output signal upon determining that said predetermined and received codes are identical until said external power is removed from said microcomputer 61 The security system as defined by claim 9 wherein said comparator means compares said first predetermined code with said received code responsive to said external power source being applied to said microcomputer 62 The security system as defined by
30. henever the microcomputer is initially coupled to a power source The user must enter a primary security code which is compared to a predetermined code and if the codes match the mi crocomputer signals a relay to provide power to the device thereby enabling it Once enabled the user need not reenter the security code as long as the external source of power to the device remains uninterrupted A secondary security code may be entered if the primary code has been forgotten or misplaced Upon entry of the secondary code the microcomputer displays an encrypted version of the primary security code If an incorrect code is entered by the user the microproces sor executes an alarm routine which may include visual and audible warnings 16 Claims 2 Drawing Figures U S Patent Aug 5 1986 Sheet 1 of2 4 604 708 24 26 Ho T 25 ONLA S 28 32 34 KOM MC PROM CONTROL LVABLE SENA S 17 36 Dc RELAY DRWER 20 Wi 8 LOG C POWER SUPPLY 36 dc 6 3 14 RR U S Patent Aug 5 1986 Sheet2of2 4 604 708 ENTER ON PBWER UP N y 4ST SEC Coat CLTKEY nee y EF PD y SEC CODE eee emer DIG PI a a mad KAST N PC DEIT x tas Wo Code y ONG PROVIDE BWER TO _FROTECTED DEVICE UKAY Aor AOUMTIONS OPTIONAL KANI TONE War 4 LY BHD SOOS POR OTHER JUNCTION S EXECUTE FONCTIONS aar S00 ALS R 4 604 708 1 ELECTRONIC SECURITY SYSTEM FOR EXTERNALLY POWERE
31. if the protected device requires a microcomputer for operation the present invention may be realized without relay driver 18 or the main power relay 22 Rather than enabling the device by coupling external power to it microcomputer 10 may be programmed to withhold all command and control functions necessary to operate the device until a proper security code is entered As disclosed in the presently preferred embodiment upon the application of external power to the device microcomputer 10 exe cutes the aforementioned power on routine Only upon the entry by a user of a proper code would microcom puter 10 accept and issue the required control signals needed to operate the device Once the correct code is entered the user would not be required to reenter the code as long as power to the microcomputer remains uninterrupted In addition it will be apparent that al though in the presently preferred embodiment the pow er on routine and security codes are stored in ROM 32 and PROM 34 respectively memory means within the microcomputer 10 itself may be used for substantially the same purpose The security system of the present invention provides the owner of the device with a level of security hereto fore not known in the prior art A thief who removes a device protected by the present invention will be unable to use the device and thus once aware that the device is so protected will likely be deterred from removing it Moreover unlike devices
32. lly during the course of a day the requirement of entering a code each time operation is desired is extremely inconvenient Furthermore individuals who are not residents of the consumer s household such as baby sitters and house 10 20 25 30 35 40 45 50 55 60 65 2 guests would have to be provided with the particular pass code in order to operate a device so protected thereby potentially compromising security Moreover in a home or business equipped with several pass code protected devices known in the prior art the require ment of remembering which pass code enables which device would likely prove intolerable Thus it is likely that consumers would not purchase a device which incorporates a pass code security system as was typical in the art prior to the present invention since any secu rity benefit would be perceived as outweighed by the inconvenience factor in using the device In addition with systems such as Schulman and Launzel it is possible for a thief to alter or destroy the serial number of a stolen device and render tracing difficult if not impossible in many cases Furthermore an unauthorized user could likely obtain the pass code by contacting the manufacturer of the device and repre senting that he is the true owner inasmuch as the manu facturer had no straightforward method to check the credibility of the inquiring individual Accordingly there exists a need for a security system
33. mining that said first predetermined and received codes are identical 113 The security system as defined by claim 105 wherein said input means comprises a keypad 114 The security system as defined by claim 105 wherein said microcomputer further controls the operation of at least a portion of said electronic system other than said security system 115 The security system as defined by claim 105 wherein said comparator means continuously produces said first output signal upon determining that said first predetermined and received codes are identical until said external power is removed from said microcomputer 116 The security system as defined by claim 105 wherein said comparator means selectively produces said first ousput signal responsive to user actions upon determining that said identical until said external power is removed from said microcomputer 117 The security system as defined by claim 105 wherein said second predetermined code is used for a security related function 118 The security system as defined by claim 105 wherein said first and second predetermined codes are different from each other 119 The security system as defined by claim 105 wherein said microcomputer is programmed to use said first and second predetermined codes for different functions 120 The security system as defined by claim 119 wherein said first and second predetermined codes are used for different security related functions 121 The securi
34. ns 29 The security system as defined by claim 1 wherein said relay means comprise a relay driver coupled to said comparator means said relay driver receiving said first output signal and generating a relay drive signal responsive thereto and a relay coupled to said relay driver said relay coupling said external power source to said protected device responsive to receiving said relay drive si gnal from said relay driver 30 The security system as defined by claim 1 wherein said comparator means continuously produces said first output signal upon determining that said first predetermined and received codes are identical until said external power is removed from said microcomputer 31 A security system for protecting an externally powered protected device corresponding to ail or a portion of an electronic system such that once said device has been enabled it will remain capable of being operated unless the security system is disconnected from the external power source said security system comprising relay means coupled between said external power source and the protected device and connected to be actuated by a first output signal such that external power is provided to enable the protected device by selectively coupling said external power source to said device upon receipt of said first output signal a microcomputer connected to said external power source independently of whether or not said protected device is coupled to said ext
35. on of the protected device In addition it will be noted that the secondary code need not be unique to each device but may be common to the entire production run model or series Further more it will be appreciated that the serial number of a particular device may be cross referenced by the manu facturer to the encrypted version of the primary secu rity code or that the PROM 34 may contain the serial number which can be accessed only upon entry of the secondary code Thus the actual serial number of a device protected by the present invention can more readily be traced by law enforcement agencies even after a thief has altered or destroyed the serial number located physically on the device itself It will be apparent to one skilled in the art that al though the presently preferred embodiment as dis closed utilizes an A C source for external power the invention can be readily applied to D C external sources such as for example an automotive electrical system In the case of a D C system the logic power supply 12 would both regulate and provide the appro priate D C current and voltage for the microcomputer 10 Similarly additional obvious modifications to the invention to render it compatible with a D C source would be made Thus the present invention may be adapted to protect electronic devices used on automo biles aircraft or watercraft such as for example radio receivers and tape decks It will be appreciated that
36. ondary code which upon entry into the security system s microcom puter causes to be displayed an encrypted version of the primary security code The manufacturer using an de cryption algorithm then provides the primary security code to the user Additionally the primary code may be cross referenced to the device s serial number to facili tate tracing by law enforcement agencies BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a block diagram illustrating the security system of the present invention FIG 2 is a flow diagram showing the sequence of steps that the microcomputer executes when power is first applied to the protected electronic device 4 604 708 3 DETAILED DESCRIPTION OF THE INVENTION A security system for electronic devices such as tele visions radio receivers and the like which require an external source of power is disclosed In the following description for purposes of explanation specific num bers etc are set forth in order to provide a thorough understanding of the present invention However it will be apparent to one skilled in the art that the present invention may be practiced without these specific de tails In other instances well known circuits and devices are shown in block diagram form in order not to ob scure the present invention in unnecessary detail Referring now to FIG 1 the present invention in cludes as a part thereof a microcomputer indicated by Numeral 10 The microcomputer can
37. oupled to said storage means and said input means for comparing said first predeter mined code with said received code and for pro ducing a first output signal upon determining that said first predetermined and received codes are identical and relay means coupled between said external power source and the protected device and connected to be actuated by said first output signal such that external power is provided to enable the protected device by selectively coupling said external power source to said device upon receipt of said first out put signal whereby said received code need only be reentered if the coupling of said microcomputer to said external power source is interrupted 2 A security system including a microcomputer for protecting an externally powered device such that once said device has been enabled it will remain capable of being operated unless the security system is discon nected from the external power source comprising a microcomputer connected to said external power source storage means for storing first and second predeter mined codes input means for receiving a code comparator means coupled to said storage means and said input means for comparing said first predeter mined code with said received code and for pro ducing a first output signal upon determining that said first predetermined and received codes are identical and relay means coupled between said external power source and the protected d
38. pled to said com parator means said relay coupling said external power source to said protected device responsive to receiving said first output signal from said comparator means 44 The security system as defined by claim 31 wherein said relay means comprise a relay driver coupled to said comparator means said relay driver receiving said first output signal and generating a relay drive signal responsive thereto and a relay coupled to said relay driver said relay coupling said external power source to said protected device responsive to receiving said relay drive signal from said relay driver B1 4 604 708 5 45 The security system as defined by claim 31 wherein said comparator means continuously produces said first output signal upon determining that said predetermined and received codes are identical until said external power is removed from said microcomputer 46 A security system for protecting an externally powered protected device corresponding to all or a portion of an electronic system such that once said device has been enabled it will remain capable of being operated unless the security system is disconnected from the external power source said security system comprising relay means coupled between said external power source and the protected device and connected to be actuated by a first output signal such that external power is provided to enable the protected device by selectively coupling said external power
39. put signal 84 The security system as defined by claim 81 wherein said protected device comprises an applicable circuit com ponent of said electronic system 85 The security system as defined by claim 81 wherein said comparator means compares each of a plurality of entries of said received code with a corresponding portion of said first predetermined code as each of said entries are entered through said input means 86 The security system as defined by claim 81 wherein said storage means comprises a semiconductor program mable read only memory integrated circuit 87 The security system as defined by claim 81 wherein said second predetermined code comprises a plurality of characters 88 The security system as defined by claim 81 wherein said external power source comprises an AC power source 89 The security system as defined by claim 81 wherein said comparator means produces said first output signal immediately upon determining that said first predetermined and received codes are identical 90 The security system as defined by claim 81 wherein said input means comprises a keypad 91 The security system as defined by claim 81 wherein said microcomputer further controls the operation of at least a portion of said electronic system other than said security system 92 The security system as defined by claim 81 wherein said comparator means continuously produces said first output signal upon determining that said first predetermined
40. re identical 70 The security system as defined by claim 9 wherein said input means comprises a keypad BI 4 604 708 7 71 The security system as defined by claim 9 wherein said microcomputer further controls the operation of at least a portion of said electronic system other than said security system 72 The security system as defined by claim 9 wherein said comparator means continuously produces said first output signal upon determining that said first predetermined and received codes are identical until said external power is removed from said microcomputer 73 The security system as defined by claim 9 wherein said comparator means selectively produces said first output signal responsive to user actions upon determining that said first predetermined and received codes are identical until said external power is removed from said microcomputer 74 The security system as defined by claim 9 wherein said second predetermined code is used for a security related function 75 The security system as defined by claim 9 wherein said Jirst and second predetemined codes are different from each other 76 The security system as defined by claim 9 wherein said microcomputer is programmed to use said first and second predetermined codes for different functions 77 The security system as defined by claim 76 wherein said first and second predetermined codes are used for different security related functions 78 The security system as define
41. rou tine in the absence of a match between said re ceived code and said first and second predeter mined codes stored within said storage means 8 The security system as defined by claim 7 wherein said input means comprises a keypad 9 A security system including a microcomputer for protecting an electrically powered device such that once said device has been enabled it will remain capable of being operated unless the security device is discon nected from an external power source comprising a microcomputer connected to said external power source storage means connected to said microcomputer for storing first and second predetermined codes input means connected to said micorcomputer for receiving a code comparator means coupled to said storage means and said input means for comparing said first predeter mined code with said received code and for pro ducing a first output signal upon determining that said first predetermined and received codes are identical coupling means connected to receive said first output signal for enabling said protected device upon re ceipt of said first output signal and whereby said received code need only a reentered if the connection of said microcomputer to said exter nal power source is interrupted 10 The security system as defined by claim 9 further including display means coupled to said comparator means for displaying alphanumeric characters 11 The security system as defined by
42. rst output signal for enabling said protected device upon receipt of said first output signal and whereby said received code need only a be reentered if the connection of said microcomputer to said external power source is interrupted 15 The security system as defined by claim 14 wherein said relay coupling means comprises an electrical relay driven by a relay driver coupled to said microcomputer means 17 The security system as defined by claim 1 wherein said comparator means compares said first predetermined code with said received code responsive to said external power source being applied to said microcomputer 18 The security system as defined by claim wherein said protected device comprises the main power supply of said electronic system 19 The security system as defined by claim 1 wherein said protected device comprises an applicable circuit component of said electronic system B1 4 604 708 3 20 The security system as defined by claim 1 wherein said comparator means compares each of a plurality of entries of said received code with a corresponding portion of said first predetermined code as each of said entries are entered through said input means 21 The security system as defined by claim 1 wherein said storage means comprises a semiconductor programmable read only memory integrated circuit 22 The security system as defined by claim 1 wherein said electronic system includes a main power switch and
43. s previously described microcomputer 10 compares the entered secondary code with a predetermined code stored in PROM 34 If the secondary code has been properly entered microcomputer 10 displays on digital display 26 an encrypted version of the primary security code The owner reports the encrypted code to the manufacturer or its representative who in turn may enter the encrypted code into a computer which applies a decryption algorithm to recover the actual primary code The manufacturer may then report or mail the actual primary code to the owner and perhaps charge a fee for the service Furthermore if additional security is required the primary code may be printed sealed and mailed automatically by for example a computer such that the code is not observable by the manufacturer s personnel The number of digits and or characters which the primary and secondary codes are comprised of may vary with any given application of the present inven tion For example in cases where higher security is desired a length of ten digits may be used However it 20 25 30 35 45 50 55 65 6 is believed that a five digit code will provide the desired level of security without being ungainly for the user Additionally it will be noted that the security codes may comprise digits characters symbols or any combi nation thereof hereinafter referred to as alphanumeric characters which is appropriate for the specific appli cati
44. source to said device upon receipt of said first output signal a microcomputer connected to said external power source upstream from the coupling of said relay means to said external power source so that said microcomputer remains connected to said external power source inde pendently of whether said relay means is coupled said external power source to said protected device storage means for storing a predetermined code input means for receiving code and comparator means included in the microcomputer said comparator means being coupled to said storage means and said input means for comparing said pre determined code with said received code and for pro ducing said first output signal upon determining that said predetermined and received codes are identical whereby said received code need only be reentered if the coupling of said microcomputer to said external power source is interrupted 47 The security system as defined by claim 46 wherein said comparator means compares said predetermined code with said received code responsive to said external power source being applied to said microcomputer 48 The security system as defined by claim 40 wherein said protected device comprises the main power supply of said electronic system i 49 The security system as defined by claim 46 wherein said protected device comprises an applicable circuit com ponent of said electronic system 50 The security system as defined by claim 40 wherein
45. stem such that once said device has been enabled it will remain capable of being operated unless the security system is disconnected from the external power source comprising a microcomputer connected to said external power source and receiving power from said external power source unless said security system is disconnected from said external power source storage means for storing a first predetermined code input means for receiving a code comparator means included in said microcomputer said comparator means being coupled to said storage means and said input means for comparing said first prede termined code with said received code and for produc ing a first output signal upon determining that said first predetermined and received codes are identical and relay means coupled between said external power source and the protected device and connected to be actuated by said first output signal such that external power is provided to enable the protected device by selectively coupled said external power source to said device upon receipt of said first output signal said relay means being coupled to said external power source down stream from the coupling of said microcomputer to said extemal power source so that said microcomputer remains connected to said external power source inde pendently of whether said relay means is coupling said extemal power source to said protected device whereby said received code need only be reentered if
46. system is disconnected from said external power source storage means connected to said microcomputer for stor ing first and second predetermined codes input means connected to said microcomputer for receiv ing a code comparator means included in the microcomputer said comparator means being coupled to said storage means and said input means for causing said micro computer to execute a power up routine comparing said first predetermined code with said received code and for producing a first output signal upon determin ing that said first predetermined and received codes are 5 10 15 35 45 50 55 65 8 identical said microcomputer being inhibited from normal operation unless said first predetermined and received codes are identical and coupling means connected to receive said first output signal for enabling said protected device upon receipt of said first output signal whereby said received code need only be reentered if the connection of said microcomputer to said external power source is interrupted 82 The security system as defined by claim 81 wherein said comparator means compares said first predetermined code with said received code responsive to said external power source being applied to said microcomputer 83 The security system as defined by claim 81 wherein said coupling means enables said protected device by selec tively coupling power to said protected device upon receipt of said first out
47. the coupling of said microcomputer to said external power source is interrupted 2 A security system including a microcomputer for protecting an externally powered protected device corre sponding to all or a portion of an electronic system such that once said device has been enabled it will remain capable of being operated unless the security system is disconnected from the external power source comprising a microcomputer connected to said external power source and receiving power from said external power source unless said security system is disconnected from said external power source 10 15 20 25 30 45 55 65 2 storage means for storing first and second predetermined codes input means for receiving a code comparator means included in said microcomputer said comparator means being coupled to said storage means and said input means for comparing said first pre determined code with said received code and for pro ducing a first output signal upon determining that said first predetermined and received codes are identical and relay means coupled between said external power source and the protected device and connected to be actuated by said first output signal such that external power is provided to the protected device by coupled said exter nal power source to said device upon receipt of said first output signal said relay means being coupled to said external power source downstream from the cou
48. ty system as defined by claim 120 wherein said microcomputer causes an encrypted version of said first predetermined code to be displayed responsive to said received codes matching said second predetermined code 122 The security system as defined by claim 105 wherein said comparator means compares a first alphanumeric char acter of said received code with a first alphanumeric char acter of said first predetermined code and in the absence of a match compares said first received alphanumeric charac ter with a first alphanumeric character of said second predetermined code 123 The security system as defined by claim 105 further including display means coupled to said comparator means for displaying alphanumeric characters B1 4 604 708 11 124 The security system as defined by claim 105 wherein an encrypted version of said first predetermined code is displayed if said received code matches said second prede termined code 125 The security system as defined by claim 105 wherein said storage means includes an alarm routine stored as a predetermined sequences of binary quantities and said microcomputer means executes said alarm routine in the absence of a match between said received code and said first and second predetermined codes stored within said storage means 10 12 126 The security system as defined by claim 105 wherein said electronic system includes a main power switch and wherein said microcomputer is coupled to
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