Abstract:
A vehicle anti-theft arrangement and method relies on matching vehicle identifiers upon detection of vehicle battery cycling to confirm whether or not the component being protected is still resident in an authorized vehicle. The arrangement and method further includes a facile way for authorized personnel to override the protection mechanism using code word entries retrievable from a component manufacturer generated database.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to theft prevention/deterrence systems for vehicular components, such as radios. More particularly, the invention pertains to audio component anti-theft systems having the capability of being overridden by authorized personnel. 
     BACKGROUND OF THE INVENTION 
     Because audio equipment installed in vehicles are essentially expensive, lightweight and small in size, audio equipment has historically been the subject of much theft. With the thriving aftermarket network, the stolen equipment may be installed in almost any other vehicle. 
     Automobile manufacturers have employed numerous methods to prevent the audio equipment from being stolen out of the vehicles. For ease of description, the audio equipment will be referred to as a car radio. It is, however, understood that the audio equipment would encompass any sound system installed within an automobile, including cassette tape and compact disc (CD) players. 
     A variety of prior art approaches have been implemented to deter or prevent theft of such components, including mechanical methods utilizing special security screws to fasten the radio to the vehicle, and electronic methods requiring an operator to insert a special security code to unlock a car radio once the vehicle&#39;s battery has cycled. For example, see U.S. Pat. Nos. 4,720,700; 4,743,894; and 4,683,462. Similarly, U.S. Pat. No. 4,808,981 discloses an automotive electronic communication apparatus which prevents the connection of an external battery to a car radio prior to stealing it, in order to prevent an interruption in the power supplied to the car radio. 
     U.S. Pat. No. 5,870,018 teaches a theft prevention technique wherein a vehicle identification number (VIN) is initially loaded into non-volatile memory of the radio at the factory. Subsequently, upon battery cycling, a currently transmitted VIN on the vehicle&#39;s communication bus is compared to the previously stored VIN. If the VINs do not match, the normal operation of the radio is disabled. However, to reinitialize the radio for subsequent operation in a new vehicle, the dealer or service center must reinitialize the new VIN as the authorized VIN using a complex diagnostic system. 
     There is a need in the art for a component anti-theft arrangement which is both transparent to the vehicle operator and easily overridable by authorized service personnel. 
     SUMMARY OF THE INVENTION 
     Accordingly, a method for overriding an anti-theft arrangement for a vehicular audio component wherein a current vehicle identification number is compared to a previously stored VIN whenever the vehicle&#39;s battery has cycled comprises storing a preselected component identifier code in a non-volatile memory of the audio component. Whenever the current VIN is not identical to the stored VIN, entry of a code into the audio component is requested, and disablement of the audio component is overridden whenever an entered code is identical to the stored preselected component identifier code. 
     In another aspect of the invention, anti-theft apparatus for a vehicular audio component includes a stored program processor associated with the audio component and including a non-volatile memory, a vehicle communication bus coupling the processor to at least one vehicle control module for receipt of data messages thereover, and a data entry element coupled to the processor for transmitting externally entered code words thereto. The processor is operable to store a first vehicle identification number (VIN) and an audio component identifier code in the nonvolatile memory, to request receipt from the manual data entry element of a code word whenever a battery cycle has been detected by reinitialization of the processor and a second VIN read from the bus is not identical to the stored first VIN, and to inhibit operation of the audio component until receipt of a code word identical to the audio component identifier code. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The objects and features of the invention will become apparent from a reading of a detailed description, taken in conjunction with the drawing, in which: 
         FIG. 1  is a block diagram of radio anti-theft apparatus arranged in accordance with the principles of the invention; and 
         FIGS. 2A ,  2 B set forth a flow chart outlining a method of radio anti-theft provisions in accordance with the principles of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts a system block diagram of an arrangement  100  for providing anti-theft protection for a battery-powered vehicular component, such as a radio. With reference to  FIG. 1 , arrangement  100  centers about a vehicle radio  104  having a microprocessor  110  equipped with random access memory  112 . Additionally, microprocessor  110  includes a non-volatile memory  108 , such as an EEPROM. 
     Also included in radio  104  is a human/machine interface, such as a plurality of data entry elements, such as pushbutton switches  118  normally associated with a faceplate  122  of the radio. 
     A programmable controller, such as a body controller  102  is coupled to radio  104  via a vehicular communication bus  106 . The electrical components of the system  100  are powered principally by a vehicular battery  114 . 
     The system and method of the invention centers around detection of battery cycling. As known to those skilled in the relevant art, a battery cycle comprises either disconnecting the battery for a time long enough for all residually stored voltages to discharge, or taking a component such as radio  104  out of its authorized vehicle and putting it into another, or replacing the battery for maintenance reasons (or at least disconnecting it from the battery terminals in the vehicle). There are various methods of detecting the occurrence of a battery cycle. One would be for a hardware battery detector to set a software flag in the radio  104  microprocessor  110  as power is going down. Preferably, we rely on the fact that in modern vehicles equipped with software in various controllers, such software is restarted and goes through an initialization routine after a battery cycle. This initialization routine can be used in and of itself to indicate that cycling has taken place. 
     With continued reference to  FIG. 1 , once battery cycling has been detected at microprocessor  110 , the radio may be disabled as detailed below where it is determined that the radio  104  has been removed from its authorized vehicle. Under these circumstances, apparatus and methods must be provided to override the theft prevention system by authorized personnel. The invention contemplates a database  120  which is generated by the manufacturer of the audio component being protected. Essentially, the manufacturer will place a unique component identifier code, preferably of four digits, for each serial number of the component produced by the manufacturer. Authorized service personnel can then access database  120  to retrieve the identifier code for the serial number of radio  104  which they wish to reinitialize. Once the code has been retrieved it is manually entered via data entry switches  118  into microprocessor  110 . Upon receipt of this code, processor  110  compares the entered code with a code stored in non-volatile memory  108  either at the component manufacturer facility or at an assembly plant when the radio is first installed in the vehicle. Upon such a match, radio  104  is re-enabled for normal operation. 
     The details of the anti-theft prevention and override method of the invention are best described with reference to the flow chart of  FIGS. 2A and 2B . Routine  200  begins at step  202  where the identifier code is stored in the radio&#39;s non-volatile memory  108 . At decision block  204 , processor  110  determines whether the ignition and the radio power are on. If not, the routine continually loops back to decision block  204  to monitor for power up. 
     If the ignition and radio power is on, the routine proceeds to decision block  206  to determine whether a VIN is resident in nonvolatile memory  108 . If no VIN is present, this indicates an initial factory installation of a vehicle battery is taking place upon assembly of the new vehicle. If this is the initial battery connection, then processor  110  at step  212  fetches a factory VIN which is being transmitted over vehicle bus  106  by elements such as body control unit  102  and stores this initial VIN in non-volatile memory  108 . The routine then returns to normal radio operation at  208 . Once the radio is turned off, the routine returns to decision step  204 . 
     If a VIN is present at step  206 , then the routine proceeds to step  214  wherein the VIN being currently transmitted on the bus  106  is compared to the factory VIN stored in non-volatile memory  108 . If the VINs match at step  214 , the routine proceeds to normal radio operation at  208 . If the VINs do not match, the routine proceeds to the flow chart of  FIG. 2B  at entry point A. 
     With reference to  FIG. 2B , the routine then proceeds to step  216  where the program in processor  110  will request entry of an identifier code via switches  118 . At decision block  218 , if the entered code matches the initially stored identifier code in non-volatile memory  108 , the software in the radio  104  proceeds to block  220  and updates or overwrites the factory VIN in non-volatile memory for subsequent use. The routine then returns to normal operation  208  in  FIG. 2A  via entry point B. 
     If the entered code does not match the code stored in non-volatile memory  108  of the radio  104 , then the routine proceeds to decision block  222  where it is determined how many incorrect entries have been made. If the number of incorrect entries is more than a preselected number N, then the routine enters into a delay cycle, e.g., for 30 minutes, at step  224  prior to returning to step  216  to continue the request for code entry. If the number of incorrect entries is less than N, the routine returns immediately to step  216 . It is therefore seen that the radio will remain disabled until a code match is found at decision block  218 . If no code has been entered pursuant to request  216 , radio  104  will continue to prompt for code entry. 
     The method and arrangement of the invention is transparent to the customer so long as either no battery cycling occurs or if it does, the VIN match indicates that the radio has remained in its authorized vehicle. Additionally, the theft prevention arrangement may be easily overridden by authorized personnel having access to a database of code identifier words stored as a function of component identification numbers, such as serial numbers. 
     The invention has been described with reference to a detailed example. The scope and spirit of the invention is to be determined only with proper interpretation of the appended claims.