SE449274B - Electronic equipment security system - Google Patents

Abstract

The system has the external main operating component of the electronic equipment, used for adjustment and control of its various functions, connected to a microprocessor which is pre-programmed to accept the effect of the external control in a specific sequence. The microprocessor is connected to a relay or other kind of switching device permitting 'on' and 'off' connection of at least one specific circuit in the electronic equipment, and is fed with current irrespective of the 'on'/'off' status of the equipment. A predetermined time after switching 'off' or fall-away of voltage feed, the electronic circuit is disconnected, and it can only be reconnected when the main operating component is manoeuvred in accordance with a given sequence. Where the sequence is fed in incorrectly, a time monitored period occurs during which new code sequences are not accepted, and where subsequently repeated feeds of erroneous sequences occur, this time monitored period is prolonged. (Provisional Basic advised week 84/06)

Description

449 274 The present invention is based on an utilization of the switches and other electrical switching means which are normally present in electronic equipment, intended to allow switching on / off, function setting, selection of channel or frequency range, or other similar functions, specific to the type concerned. of electronic equipment.

As an example of an embodiment, mention may be made here of a mobile radio receiver, which may also comprise a mobile tape recorder. Such equipment here comprises an electrical switching-on / disconnecting means, a potentiometer for adjusting the volume, a potentiometer for setting the bass / treble ratio, together with a number of switching means, partly intended to allow selection of frequency bands, but often also comprising quick selection of frequency within associated frequency bands. With respect to, for example, the latter switching means, which are usually present in a number between 4 - 12, these can advantageously be used as switching means, intended to allow practice of the method according to the present invention. The said means is in this case electrically connected to a microprocessor arranged in the mobile radio receiver, which is controlled by a program in the associated memory of the write type, i.e. PROM, E-PROM or similar. Furthermore, there is a second programmable memory, which in its simplest form can consist of a diode matrix, or an electrically or otherwise known programmable memory. The said second memory can in this case also be designed as an integrated part with the first memory. Furthermore, the microprocessor is connected to a relay or a switch transistor, or other switching means, arranged to interrupt / close the voltage supply to at least one vital part of the radio receiver.

In use, the above-mentioned switching means are pressed according to a predetermined sequence, and provided that the means are actuated in the correct order, the previously affected relay or switching means are actuated so that the radio can then be used in a conventional manner. If, on the other hand, there is an error, e.g. incorrect order, incorrectly actuated switch means or the like, a first time monitoring is started in the microprocessor during a given and predetermined time period, and during this time period no inputs are initiated, initiated by influencing previously affected external switch means at the radio receiver. As a suitable first monitoring period, a time period in the range of 30 - 60 seconds can be selected. After this first time monitoring period has elapsed, sequential input of a predetermined code sequence is again accepted and provided that this is correct, the relay or switch means which means that the radio receiver can be used is now affected. In the event that the incorrect code sequence is entered again, a second time monitoring period is started, which preferably has a greater length than the first period, but which can also be of substantially uniform length. After this second time monitoring period, input data is accepted again, and if an incorrect code sequence is again obtained, a third monitoring period begins, preferably with a length that is doubled in relation to the second monitoring period, or is of even greater length, e.g. . triple, quadruple or similar. Said time monitoring thus takes effect after each incorrectly entered code sequence, and the time period for monitoring is extended continuously, preferably by multiplying the previous monitoring period in time by a given and predetermined factor.

By continuously extending the time monitoring period in case of repeated and successive incorrect entries of the predetermined code sequence, an unauthorized person is repeatedly prevented from acquiring knowledge of the design of the code sequence through repeated attempts. It can be mentioned in this connection that there is also the possibility of achieving a considerably extended monitoring period after a certain number of attempts, e.g. in that a first factor is used in extending the monitoring period in a predetermined number of successive experiments performed, and that a second and considerably larger factor is used in subsequent experiments.

As a result, the length of a monitoring period can be extended to cover one or more days.

It is also possible to further strengthen the protection against unauthorized use by introducing a counting function with regard to the number of subsequent attempts to enter the correct code sequence, and that when a predetermined number of such attempts have been performed in continuous sequence, completely prevent the use of the radio receiver. . Thus, an available voltage potential, e.g. 12 volts, directly supplied to one or more electronic components included in the radio receiver, which are normally referred to as voltage-supplied with a lower potential, e.g. transistors, integrated circuits, diodes or the like. As a result of such a measure, one or more predetermined components are destroyed, which means that the radio receiver cannot be used without repair.

When using the present invention in mobile installations, such as mobile radio receivers and other radio communication equipment, the method can also be combined with a protection against unauthorized use of the vehicle, provided that the vehicle is equipped with such electronics that it can not be used if included electronic components are disabled. . Examples of such components are electronic ignition systems, electronically controlled injection systems and the like. Such systems can in this case be arranged comprising a relay, a switch transistor or the like, which is controlled by the microprocessor present in, for example, a radio installation in the vehicle. In order to influence the previously affected switching organ in the vehicle's electrical equipment, the previously determined predetermined code must be input to the microprocessor via existing external controls on the radio, whereby the microprocessor partly protects said radio against unauthorized use, and also the vehicle.

As previously briefly touched upon, the code sequence affecting the microprocessor can be arranged pre-programmed in various ways. Thus, it can be predetermined already in the manufacture of the electronic equipment, but it can also be arranged programmably electrically, with UV light, magnetically or in another manner known per se at a later time. Thus, the programming of a certain code sequence can also be performed at the time of sale of the equipment by means of knowledge and equipment available at the point of sale, but also later by the buyer, in that a first entry of a sequence results in programming.

The present invention may also include a further modification, namely voltage monitoring with respect to applied supply voltage.

This offers the possibility of reducing the number of times when the predetermined code sequence is to be input to only the time when there has been an interruption in the applied supply voltage. Such a function is particularly suitable for many applications, as only protection against theft is observed. In the case of, for example, television sets, stereo systems and other types of electronic equipment which are normally always connected to a voltage source, a theft attack means that interruptions occur during a certain period of time in the supplied supply voltage. Such a voltage interruption can be arranged in this case to initiate the monitoring function of the microprocessor 449 274, i.e. previously affected input of a predetermined code sequence is assumed after voltage connection has been performed.

In order to reduce the number of input operations of predetermined code sequence, a further modification can also be performed. Thus, a second time monitoring function can be introduced, which is initiated in connection with the electronic equipment being switched off after use with dedicated / disconnecting means. Provided that the equipment is still connected to a voltage source, this second time monitoring function can allow connection of the equipment with said on / off means for a predetermined period of time, without any code sequence having to be entered. Such a modification is of value in mobile electronic devices such as, for example, car radio systems intended for reception, radio communication or sound reproduction, as it is possible to disconnect such equipment when leaving the vehicle, and reconnect them when returning to the vehicle, without entering the previously affected code sequence needs to be executed. The period during which such an action can be performed can be chosen arbitrarily in time and adapted to the type and area of use of the equipment.

The present invention can be used with a particularly large number of different types of electronic equipment, both mobile and stationary equipment, as well as equipment with power supply from battery or mains-connected AC-powered equipment. In principle, the invention can be used with all such devices which comprise a number of electrical switching means or switching means, intended for use in the normal operation of the equipment.

Furthermore, indicated modifications previously discussed can also be combined arbitrarily with each other in order to obtain a solution that is well adapted to the various applications that are possible within the scope of the invention.

The present invention is thus in no way limited to any specific and limited field of use, but can be varied in a number of different ways within the scope of the inventors' idea and the appended claims.

Claims (10)

449 274 P A T E N T K R A V 1. A method of protecting electronic equipment against unauthorized use, characterized in that external operating means present in such equipment, intended to constitute function-controlling means during use of the equipment, are electrically connected to a microprocessor, which voltage is supplied separately and independently of the electronic equipment. the connection / disconnection status, and the microprocessor is electrically connected to a relay or other switching means, which by actuation from the microprocessor can switch on or off the function of at least a certain input circuit in the electronic equipment, and thereby disconnecting a function failure for said equipment, wherein the influence of the external equipment of the electronic equipment and connected to the microprocessor in a certain predetermined sequence is arranged to cause connection of the circuit included in the equipment monitored by the n fi body processor, while voltage drop with respect to out the equipment connected to a voltage source and / or the input of a sequentially subsequent code sequence via the external actuators which do not correspond to a pre-programmed sequence results in a disconnection of the circuit in the electronic equipment which is monitored by the microprocessor. 2. A method according to claim 1, characterized in that the disconnection function of the microprocessor is initiated a certain period of time after the electronic equipment has been disconnected from the connected voltage source by means of associated disconnection means, and that connection can be performed before said time period without predetermined code. is entered via the external control device of the electronic equipment. 3. A method according to any one of claims 1 and 2, characterized in that the number of consecutive erroneous code sequence entries is counted, and that a time monitoring is introduced after a predetermined number of such operations, wherein entry of code sequences during the time monitoring period is not accepted or is compared with a predetermined code sequence and does not result in a change in the disconnection status of the circuit in the electronic equipment monitored by the microprocessor. W; 449 274 u 4. A method according to claim 3, characterized in that the time-monitored period is extended by multiplying by a certain factor for each subsequent time period caused by an incorrectly entered code sequence. 5. A method according to claim 3, characterized in that the time-monitored period is extended by multiplying by a first and predetermined factor during a predetermined number of consecutive time-monitored periods caused by subsequent incorrectly entered code sequences, and that said factor is increased with respect to thereafter. the following time-monitored periods caused by additional subsequent and incorrectly entered code sequences. 6. A method according to any one of claims 1 to 5, characterized in that the number of consecutive erroneous code sequence inputs is counted, and that one or more components in the monitored electronic equipment are energized with an excessively high voltage potential for disturbing purposes when the number erroneous and consecutive code sequence entry operations exceed a predetermined number, 7. A method according to any one of claims 1 to 6, characterized in that the microprocessor is connected to at least two relays or switch means, one in the electronic equipment whose control means are used for code sequence input and connected to a circuit included therein, the other connected to a circuit in a second nearby electronic equipment. Device for practicing the method according to any one of claims 1 to 7, characterized in that it comprises a microprocessor arranged in an electronic equipment, electrically connected to a number of external operating means in said equipment used for function check determination when using the equipment, furthermore, a relay or a switching means is arranged as an integral part of the electronic equipment, arranged to allow at / when actuated by the microprocessor at least one circuit which upon disconnection causes a failure of the equipment, whereby actuation of the external operating means according to a predetermined sequence causes the circuit present in the electronic equipment to be switched on by means of the switch means controlled by the microprocessor, while incorrectly entered code sequence and / or loss of voltage in the voltage connection of the monitored electronic equipment causes disconnection to be performed with respect to controlled circuit, wherein the microprocessor is voltage supplied regardless of the electronic equipment's on / off status relative to a voltage source for the equipment, whereby disconnection caused by voltage failure in the supply circuit to the equipment can only be canceled by entering the correct code sequence via the equipment's external control. Device according to claim 8, characterized in that the microprocessor, when obtaining an incorrect code sequence from the external operating means, is arranged not to accept new input data for a certain period of time, and that said time period is successively extended for each subsequent incorrect input operation. Device according to one of Claims 8 and 9, characterized in that the microprocessor is arranged to count consecutive incorrect input operations of code sequences, and to supply at a predetermined number at least one component included in the monitored electronic equipment a voltage potential which exceeds the maximum permissible voltage potential for the component in question, whereby said voltage potential is supplied for destructive purposes with the intention of causing a malfunction of the monitored equipment.