Abstract:
A security system and method for protecting an item of merchandise includes a programming station including a logic control circuit having a controller, a communication circuit operably coupled to the controller, and a memory operably coupled to the controller for initially providing a security disarm code (SDC) to a programmable key including a logic control circuit having a controller, a communication circuit operably coupled to the controller and a memory operably coupled to the controller. The programmable key subsequently provides the SDC to a security device configured for attachment to the merchandise and including a logic control circuit having a controller, a communication circuit operably coupled to the controller, and a memory operably coupled to the controller. Thereafter, the security device is disarmed by using the programmable key to verify the SDC in the memory of the key with the SDC in the memory of the security device. A wireless interface is provided for the communication circuit of the programming station, programmable key and security device. An internal timer in the programmable key invalidates the SDC after a preset period of time period to prevent use of the key for disarming a security device after the time period has expired.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 11/639,102, filed on Dec. 14, 2006, now U.S. Pat. No. 7,737,846, which claims the benefit of U.S. Provisional Application No. 60/753,908, filed on Dec. 23, 2005, the entire disclosures of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to security devices, systems and methods for protection of merchandise, and in particular to a system based on a smart key that is programmed with a security disarm code (SDC) at a programming station, which key is used to program the SDC into various alarm modules attached to items of merchandise. 
     BACKGROUND OF THE INVENTION 
     Various retail establishments use numerous types of theft deterrent devices and systems to discourage shoplifters. Many of these systems use alarm modules or other security devices which are attached to the article to be protected in one manner or another. When the integrity of the module or the item of merchandise protected thereby is compromised in any manner, such as cutting cables which attach the security device to the item of merchandise, removing the merchandise from the security device or disturbing the security device, will cause an audible alarm to be sounded in the security device to alert store personnel that the item of merchandise or security device is being tampered with illegally. These security devices, as well as the items of merchandise protected thereby, also may contain various electronic article surveillance tags (EAS) which will sound an alarm at a security gate upon passing through the gate in an unauthorized manner. 
     These alarm modules or security devices which are attached to the items of merchandise usually have some type of key, either mechanical or magnetic, which is used to unlock the device from the protected item of merchandise to enable the merchandise to be taken to a checkout counter, as well as to disarm the alarm contained in the alarm module. One problem with such security systems is that these keys will be stolen from the retail establishment and used at the same establishment or at another store using the same type of alarm module or security device, to enable a thief to disarm the alarm module as well as unlock it from the protected merchandise. These keys also are stolen by dishonest employees for subsequent unauthorized use by the employee or sale to a thief for use at the same or other stores which use the same type of alarm modules and security devices controlled by the key. 
     It is extremely difficult to prevent the theft of these keys by dishonest employees or even by a thief within the retail establishment due to the number of keys that must be available and used by the clerks in the various departments of the store to facilitate the use of the numerous alarm modules and security devices that are needed to protect the numerous items of merchandise. 
     Thus, the need exists for a security system which uses various types of alarm modules and security devices which are attached to various items of merchandise, which will prevent a thief or dishonest employee from using the key that is needed to disarm and unlock the security device in an unauthorized manner on similar types of alarm modules at various retail establishments including the store from which the key was stolen. 
     BRIEF SUMMARY OF THE INVENTION 
     One aspect of the present invention is to provide a security system and method for protecting items of merchandise which use a smart key for disarming the security device which is attached to the merchandise, which key is programmable with a unique security disarm code (SDC), which code is provided to the key by a programming station, wherein the SDC is unique to a particular retail establishment, thereby preventing the key from being used at a different store than that from which the key is stolen. 
     A further aspect of the present invention is to use the SDC which is programmed into the smart key by a programming station, to program each of the individual alarm modules or security devices used in that store with the same SDC when the alarm modules and devices are first activated, which SDC remains with the alarm module throughout its use in the particular retail establishment. 
     Another aspect of the present invention is to provide such a security system in which the smart key is provided with an internal timer which after a preset period of time, for example 96 hours, will automatically invalidate or erase the SDC in the key thereby preventing its unauthorized use even in the particular retail establishment in which the programming station is located and the SDC was initially programmed into the key, after the preset time period. 
     A further feature of the present invention is to require the smart key to be reprogrammed with the SDC by the programming station within a preset time period, which reprogramming can be performed by authorized personnel insuring that the key can only be used by authorized clerks, and only in the store having the programmable station and the single unique SDC for all of the security devices in the store. 
     Another feature of the present invention is to provide the smart key with an internal counter which counts the number of activations performed by the key, that is, the initial activation of every alarm module as well as each time the key is used to disarm one or more of the alarm modules, and upon a predetermined number of activations occurring will permanently inactivate the key thereby ensuring that an active key always has sufficient internal power to receive the SDC and subsequently communicate with the alarm modules for disarming the modules when required. Furthermore, the internal counter will actuate an indicating signal a predetermined time period before permanently deactivating the control circuit of the key after the maximum number of activations have been provided by the key. 
     Still another aspect of the present invention is to provide wireless communication between the various elements of the system, namely the smart key, programming station and alarm module based upon infrared (IR), radio frequency (RF) or similar wireless transmission systems. 
     A still further aspect of the present invention is to enable the alarm module or security device to actuate an alarm if a key is attempted to be used to disarm the alarm module containing a wrong SDC. 
     Still another feature of the present invention is to retain the SDC in the programming station within a non-volatile memory enabling it to survive a power interruption. 
     A further aspect of the present invention is to enable the programming station upon reading a SDC stored in a key which does not match the SDC of the programming station to immediately time out the wrong SDC programmed into the key preventing subsequent use of the key. 
     Another feature of the present invention is to provide the programming station with a plurality of visual indicators which are illuminated and/or pulsed to indicate the status of the programming station. 
     Still another aspect of the present invention is the incorporation of an operational lifetime timer into the logic control circuit of the alarm module which is preset for a specific period of time to ensure that the self-contained battery has sufficient charge for operating the alarm module; and that the alarm module includes a counter which records the amount of time that the audible alarm is activated, which alarm activation time automatically reduces the lifetime period in the lifetime timer by a predetermined amount. The lifetime counter automatically disables the alarm module at the end of the adjusted lifetime. 
     A further aspect of the present invention is that the lifetime counter in the alarm module will activate an end-of-life signal a predetermined time period before the lifetime timer completely disables the alarm module enabling store personnel to replace the same with a new and sufficiently charged alarm module. 
     Another feature of the present invention is to mount a piezo electric audible alarm in the alarm module in direct communication with an open sound space formed between the bottom of the alarm module and mounting base to increase the dB level of the alarm sound more than that obtainable if the alarm was mounted entirely internally within the alarm housing. 
     A further feature of the present invention is to provide the alarm module with a plurality of connection ports for attachment of one or more attachment cables extending between the alarm module and items of merchandise, which cables will contain a sense loop which will sound an alarm within the module if the integrity of the sense loop is compromised by a thief. 
     Another aspect of the present invention is to enable the logic control circuit of the programming station to permanently inactivate the SDC in a smart key if the SDC contained therein does not match that of the programming station when in communication with the logic control circuit of the programming station. 
     Still another aspect of the present invention is to provide the programming station with a plurality of LEDs which provide various status displays depending upon the condition and state of operation of the programming station. 
     Another feature of the present invention is to provide the programming station with a mechanically actuated tumbler switch requiring a key to operate, which key can be controlled by the store manager or other authorized personnel in order to activate the programming station for the initial and subsequent programming of the SDC into the smart keys. 
     Still another feature of the present invention is to provide the programming station with mechanical attachment means for securing it to a supporting structure in a secure location wherein the programming station is connected to an external power source ensuring that the required power is always available at the programming station avoiding the use of an internal battery power supply source. 
     A further aspect of the present invention is to provide the key and alarm module with a light pipe which will facilitate the transfer of the IR wireless communication wavelengths between the key and alarm module. 
     Another aspect of the present invention is to form a portion of the housing of the programming station of an infrared clear plastic material to facilitate the transmission of IR waves between the wireless communication systems of the key and programming station. 
     Still another feature of the present invention is to form the sense loops extending between the alarm modules and attached items of merchandise of an electrical conductor or fiber optic conductor located within an outer mechanical attachment cable. 
     These aspects and features are obtained by the security system of the present invention the general nature of which may be stated as including a programmable key, a programming station for generating a security disarm code (SDC) in the key, a security device for attachment to an item of merchandise, said security device receiving the SDC from the key when initially activated and for subsequent use to disarm the security device. 
     These aspects and features are further obtained by the method of the present invention used for protecting an object, the general nature of which may be stated as including the steps of attaching an alarm module to the object, programming a key with a security disarm code (SDC), programming the SDC into the alarm module from the key, disarming the alarm module by verifying the SDC in the key with the SDC in the alarm module by wireless communication between the key and alarm module, and invalidating the SDC in the key after a period of time to prevent subsequent disarming of the alarm module by said key unless the SDC is refreshed in the key within said period of time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of the invention, illustrating the best mode presently contemplated for applying its principles, is set forth in the following description and is shown in the drawings, and is particularly and distinctly pointed out and set forth in the appended claims. 
         FIG. 1  is a diagrammatic view of the principal components of the security system of the present invention. 
         FIG. 2  is a diagrammatic side elevational view of the programming station component of the security system. 
         FIG. 3  is a cross-sectional view of the programming station of  FIG. 2 . 
         FIG. 4  is a block diagram of the logic control circuit of the programming station shown in  FIG. 2 . 
         FIG. 5  is a diagrammatic side elevational view of one type of security device which can be used in the security system of the present invention. 
         FIG. 6  is a cross-sectional view of the security device of  FIG. 5 . 
         FIG. 7  is a block diagram of the logic control circuit of the security device shown in  FIG. 5 . 
         FIG. 8  is a plan view of the programmable smart key of the security system shown in  FIG. 1 . 
         FIG. 9  is a cross-sectional view taken on line  9 - 9  in  FIG. 8 . 
         FIG. 10  is a block diagram of the logic control circuit of the programmable key shown in  FIG. 8 . 
         FIGS. 11 ,  11 A and  11 B are a flow chart of the control circuitry of the programmable key shown in  FIG. 8 . 
         FIGS. 12 ,  12 A and  12 B are a flow chart of the control circuitry of the programming station shown in  FIG. 2 . 
         FIG. 13  is the flow chart of the control logic circuit for the security device shown in  FIG. 5 . 
         FIGS. 14 ,  15 ,  16  and  17  are diagrammatic views of other types of security devices which can be used with the security system of the present invention. 
     
    
    
     Similar reference numbers and characters refer to similar parts throughout the various drawing figures. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of the improved security system of the present invention is indicated generally at  1 , and is shown in  FIG. 1 . Security system  1  includes three main components, a programming station  3 , a programmable smart key  5  and an alarm module or security device  7  which is adapted to be attached to an article of merchandise  9  by an attachment device such as a cable  11 , which preferably contains a sense loop  13 . 
     Programming station  3  preferably is of the type shown and described in greater detail in related U.S. application Ser. No. 11/638,814, filed on Dec. 14, 2006, now U.S. Pat. No. 7,737,844 entitled P ROGRAMMING  S TATION  F OR  A S ECURITY  S YSTEM  F OR  P ROTECTING  M ERCHANDISE , the entire disclosure of which is incorporated herein by reference. Programming station  3  is shown in  FIGS. 2-4  and includes a housing  15  formed by an internal housing shell  16  preferably formed of an infrared clear plastic material to facilitate the transfer of infrared wireless communication waves, as discussed further below. Housing  15  furthermore includes a top cover plate  14  snap-fitted onto shell  16  and a printed circuit board  17  containing a logic control circuit  18  located therein. Logic control circuit  18  is shown in block diagram form in  FIG. 4 . 
     Logic control circuit  18  includes a main controller  19  which preferably is a microprocessor, a wireless communication circuit  20  and a security disarm code (SDC) memory  21  communicating with controller  19 . A status display  22  which consists of three LEDs  24  also is part of logic control circuit  18  and provides a visual indication of the status of programming station  3  during and after the use of programming station  3  for programming the SDC into smart key  5 . Housing shell  16  is secured to a base  24  by fasteners  25 , which base can be secured to a supporting structure  26  by fasteners  27 . Wireless communication circuit  20 , and in particular the transmission and receive components thereof, are aligned with a key receiving port  29  formed in housing shell  16 , which port is adapted to receive smart key  5  therein as shown in  FIG. 2 . Wireless communication circuit  20  and the various components thereof which are formed on circuit board  17 , in the preferred embodiment will be an infrared (IR) system, although radio frequency (RF) or other types of wireless communications could be used without affecting the concept of the invention. 
     A key-actuated tumbler switch  31  is mounted in housing  15  and is controlled by a mechanical key  33  for activating the logic control circuit  18  within programming station  3  for programming a smart key  5  with the SDC as discussed further below. The particular circuitry of logic control circuit  18  is shown in further detail in the above-referenced related patent application, but could be other types of circuitry than that shown therein, which circuits are readily known to those skilled in the art for obtaining the features and results of the programming station as discussed further below. 
     Programming station  3  preferably is powered by an external power supply such as a usual 120 volt electrical outlet readily found in a retail establishment. Preferably, station  3  will be secured to support surface  26  in a secure location, such as the store manager&#39;s office or similar protected environment. Likewise, activation key  33  will be kept in the possession of the store manager or other highly trusted employee to prevent the unauthorized use of programming station  3 . 
     Alarm module  7 , shown particularly in  FIGS. 5 ,  6  and  7  is one type of security device which can be used with the security system of the present invention. Alarm module  7  is of the type shown and described in greater detail in related U.S. application Ser. No. 11/638,727 filed on Dec. 14, 2006, now U.S. Pat. No. 7,737,843 entitled P ROGRAMMABLE  A LARM  M ODULE  A ND  S YSTEM  F OR  P ROTECTING  M ERCHANDISE , the entire disclosure of which is incorporated herein by reference. Alarm module  7  includes a housing  35  preferably formed of plastic material which includes a top cover plate  36  which is snap-fitted on a top housing member  37 , which in turn is secured to a bottom housing member  38  by a plurality of fasteners  39 . Aligned posts  40  extending between a base  41  and bottom housing member  38  provides an open sound space  42  therebetween as shown in  FIG. 6 . 
     A battery  44  is mounted in the interior of housing  35  and provides the source of power to a logic control circuit indicated generally at  46 , and shown diagrammatically in  FIG. 7 , which logic control circuit  46  is formed on a printed circuit board  48  mounted within housing  35 . Logic control circuit  46  includes a main controller  49  and a wireless communication circuit  50 , which preferably is an IR system to match that of programming station  3  as discussed above. Logic control circuit  46  furthermore includes an audible alarm  51 , which preferably is a piezoelectric alarm mounted within housing  35  and communicating directly with sound space  42  as shown in  FIG. 6 . Logic control circuit  46  further includes a SDC memory  53 , an EAS tag detector circuit  54 , and one or more sense loops  13 . A plunger switch  57  preferably is mounted within bottom housing member  38  and includes a plunger  58  which engages a support surface  59  on which alarm module  7  is mounted, preferably by one or more attachment screws (not shown). Plunger switch  57  will actuate alarm  51  if the alarm module is illegally removed from the supporting surface. An LED  61  is connected to logic control circuit  46  and extends through an opening formed in top housing member  37  and cover plate  36  to provide a visual indication of the status of alarm module  7 . 
     One or more connection jacks  63  are formed in alarm module  7 , for connecting an attachment cable  11  to alarm module  7 , which cable  11  contains a sense loop  13 . Sense loops  13  preferably are electrical conductors, fiber optic conductors or the like, which as shown in  FIG. 1  extend between alarm module  7  and an item of merchandise  9  to be protected thereby. Each sense loop  13  is operationally connected to controller  49  so that should the integrity of the sense loop  13  or cable  11  be compromised, such as by cutting of the cable  11 , or by pulling the cable  11  loose from alarm module  7  or from merchandise  9 , controller  49  will sound audible alarm  51 , as well as provide a certain flashing pattern to LED  61 . If desired, cable  11  could be connected to an automatic recoiler located within alarm module  7  without affecting the concept of the invention. The main feature is that the sense loop, and in particular conductor  13  thereof, is optically or electrically connected to controller  49  and to an item of merchandise  9 . 
     A key receiving port  65  is formed in top cover plate  36  and top housing member  37  of housing  35  adjacent a light pipe  67  to enhance the transmission of infrared signals when smart key  5  is placed in port  65  and aligned with the transmitter and receiver  69  mounted on circuit board  48  below port  65  as shown in  FIG. 6 . This facilitates the transmission of IR waves between key  5  as discussed further below, and the wireless communication components  69  of communication circuit  50 . Further details and manner of operation of alarm module  7  are shown and described in the above-referenced related patent application, and it is readily understood that other types of circuit arrangements than that shown therein and shown in  FIG. 7  could be utilized to achieve the features of alarm module  7  without affecting the concept of the invention. 
     Smart key  5  is shown in detail in  FIGS. 8-10 . Key  5  includes a housing  71  formed by upper and lower plastic housing members  72  and  73  respectively, which are joined together to form a hollow interior  74  in which is mounted a battery  75  and a printed circuit board  76  containing a logic control circuit indicated generally at  77 , and shown in block diagram form in  FIG. 10 . As shown in  FIG. 10 , logic control circuit  77  will include a wireless communication circuit  79  which preferably is IR operated so as to be compatible with the send and transmit components of programming station  3  and alarm module  7 . A central controller  80 , which preferably is a type of microprocessor, controls wireless communication circuit  79 , a SDC memory  81 , an internal timer  82  and an activation counter  83 . Logic control circuit  77  is energized by an activation switch  85  which is mounted on circuit board  76  and located beneath a flexible member  87  mounted in upper housing member  72 , so that when depressed as shown by Arrow A in  FIG. 9 , it will actuate the controller  80  and logic control circuit  77 . 
     A light pipe  89  preferably is mounted in upper housing member  72  in alignment with an LED  90  mounted on circuit board  76 . LED  90  provides a visual indication of the status and activation of key  5  as discussed further below. A lens  91  is mounted in an opening  92  of housing end  93 , which preferably is a visible light filter to enhance the transmission and reception of infrared waves when the key interfaces with programming station  3  and alarm module  7 . Again, details of the circuitry and components of logic control circuit  77  are shown in the above-referenced related patent application showing one example of a preferred circuit arrangement. However, it is readily understood that other circuit configurations can be utilized to achieve the results and features of key  5  than that shown and discussed above and in the related patent application without affecting the concept of the invention. 
       FIG. 1  best illustrates the preferred system and method of the present invention. Programming station  3  is actuated by use of security key  33  which is placed in a circular key opening  95  which energizes the station. Smart key  5  is placed in key receiving port  29  and key switch  85  is actuated by depressing downwardly on flexible member  87 . This causes logic control circuit  18  of programming station  3  to randomly generate a unique SDC which is transmitted via wireless communication circuit  20  to wireless communication circuit  79  of key  5  which stores the generated SDC in SDC memory  81  of the key. One or more of the LEDs  24  of programming station  3  and LED  90  of key  5  will illuminate or flash to indicate that station  3  is activated and operating satisfactorily, and that the SDC has been transmitted to key  5 . 
     In accordance with one of the features of the invention, the SDC which is initially generated by programming station  3  is randomly generated and is unique to station  3  and always remains with the station for subsequent use. Thus, when the first SDC is generated, this is the SDC that always stays with station  3  and is subsequently programmed into one or more keys  5 . Key  5  now containing the SDC is taken to one or more alarm modules  7  and key end  93  is inserted into key receiving port  65  as shown in  FIG. 5 . Key switch  85  is then actuated, thereby programming the SDC via the wireless communication systems  50  and  79  from key  5  into SDC memory  53  of logic control circuit  46  of alarm module  7 . SDC memory  53  permanently stores this SDC in the programmed alarm module  7 , preferably for the life of the alarm module. Again, upon actuation of key switch  85 , key LED  90  will flash as well as LED  61  of alarm module  7  indicating that a successful programming of the alarm module with the SDC has occurred. 
     In accordance with another of the features of the invention, the SDC when stored in memory  81  of key  5  will actuate a timer  82  for a predetermined time period, for example 96 hours. At the end of this time period, the SDC in memory  81  will automatically be erased or invalidated by logic control circuit  77 , thereby rendering the key inoperative if attempted to be used with alarm module  7 . This prevents a key  5  from being stolen by a thief or dishonest employee and attempted to be reused after passage of this time period to disarm an alarm module  7  in the same store from which the key was stolen. Furthermore, since the SDC in key  5  is unique to the particular programming station  3  of that retail establishment, even if key  5  is taken to another store using the same type of alarm module  7  when still within the valid time period of the SDC, the key will not function with the other store&#39;s alarm module since it will have been programmed with a different SDC. Thus, programmed key  5  prevents one of the main drawbacks of current security systems which uses various types of keys, since these prior security keys can always be used at one or more stores which use similar types of security devices, whether the key is a mechanical or magnetic actuated type of key. Thus, key  5  could only be used for a relatively short period of time by a thief or a dishonest employee, and only in the particular store from which it was stolen. This preset time period could always be adjusted to 24 hours, 36 hours etc. without affecting the concept of the invention, although 96 hours has been found to be the preferred time period. Again, the transmission of the SDC between programming station  3  and key  5 , and subsequently between key  5  and alarm module  7 , is by the wireless communication transmission systems, preferably operating on IR or RF wavelengths. 
     Counter  83  of key logic control circuit  77  counts each time that key switch  85  is activated, whether when programmed with an SDC from programming station  3  or disarming an alarm module  7 . After a predetermined number of activations, for example 55,000, counter  83  will cause logic control circuit  77  to inactivate the key  5  rendering it inoperative for further use. This ensures that battery  75  always has a sufficient charge for the transmission of the SDC between the key  5  and the programming station  3 , and between the key  5  and the alarm module  7 . 
     In order to disarm alarm module  7 , a validly programmed key  5  which is still within its active time period, will be placed into key receiving port  65  as shown in  FIG. 5  and switch  85  is energized by depressing member  87 . Wireless communication systems  50  and  79  will deactivate alarm  51  enabling cable  11  to be removed from an item of merchandise  9  or from the alarm module jack  63  for sale of the merchandise to a customer or for attachment of a new or different type of merchandise to the alarm module  7 . After the desired product manipulation has occurred, key  5  is then used to rearm the alarm module  7 . Again, key LED  90  and alarm module LED  61  will flash in various patterns to indicate that the disarming has occurred and then subsequently that the rearming has occurred. Again, SDC memory  53  of alarm module  7  must read the same SDC generated by key  5  in order to disarm alarm module  7 . If a different SDC is sensed by alarm module  7  than that stored in memory  53 , module  7  will sound alarm  51  indicating that an incorrect key  5  is being used. Likewise, if the SDC had been removed from the key  5  by timer  82 , the key will not operate or disarm the alarm module  7  and will provide a flashing signal that the disarming has not occurred and that an uncoded key is being used. 
     Furthermore, as shown in  FIG. 6 , the formation of sound space  42  and its direct communication with piezo alarm  51  will provide a greater dB level for the same size alarm than that which occurs in prior alarm modules wherein the piezo alarm is mounted entirely within the alarm module housing. Alarm module  7 , and in particular logic control circuit  46 , contains an end of life (EOL)  97  or lifetime timer which is actuated when alarm module  7  is first energized. This timer has been preset at the factory for a specific time period, for example three or five years, depending upon the particular size of battery  44  contained therein. At the end of this lifetime period, control logic circuit  46  will deactivate alarm module  7  preventing its subsequent arming with an SDC. This ensures that the battery has sufficient power throughout the useful life of the alarm module. Furthermore, a counter  98  is provided in the alarm module which records the length of time that alarm  51  is operated since the alarm results in additional drain to the battery charge. This alarm time is then subtracted from the EOL period by a certain formulation. Again, this ensures that battery  44  has sufficient power to satisfactorily operate alarm module  7  even though the audible alarm has been used a number of times during its life. 
     A near end-of-life (NEOL) feature is also provided in logic control circuit  46  which will provide a visual signal, such as a particular flashing pattern of LED  61  and a different non-alarming chirping sound from alarm  51 , when the end-of-life time out is approaching, for example five days before the end-of-life timer completely inactivates the alarm module circuitry. 
     Further details of the operation of logic control circuit  77  of programmable key  5  are shown in  FIGS. 11 ,  11 A and  11 B.  FIGS. 12 ,  12 A and  12 B shows additional details of the manner and method of operation of the logic control circuit  18  of programming station  3 , with  FIG. 13  showing the manner of operation of the logic control circuit  46  of alarm module  7 . The sequence of events and actions taken by these various components shown in the flow charts of  FIGS. 11-13  are readily understood and followed by one skilled in the art. 
       FIGS. 14-17  show examples of four other types of security devices which could be used in the security system and method of the present invention.  FIG. 14  shows a product display security device indicated at  100  for displaying and protecting an item of merchandise  101  attached to a cable  102  which would contain a sense loop. A smart key receiving port  103  is formed in the security device housing  104 , which when a key  5  is inserted therein would initially program and then subsequently disarm security device  100 .  FIG. 15  shows a type of garment tag security device  105  which is formed with a smart key receiving port  106  which is used to deactivate the security tag to enable a pin alarm  107  to be removed from a garment  108 .  FIG. 16  shows another type of cable alarm security device  109  which is connected about an item of merchandise  110  by a cable  111 . Cable  111  contains a sense loop and will be formed with a smart key receiving port  112  therein in order to deactivate security device  109  enabling it to be removed from protected item  110 . Still another type of security device, indicated generally at  115 , is shown in  FIG. 17  which includes a plurality of cables  116  which extend about an item  117  to be protected thereby. It is readily understood that cables  116  preferably contain sense loops and are tightened about package  117  by a ratchet mechanism  118 . A smart key receiving port  119  is provided, along with a logic control circuit, within a housing  120  containing the ratchet mechanism.  FIGS. 14-17  merely show other examples of how the security system of the present invention and its method of operation can be utilized and that it need not be limited to the particular alarm module  7  shown and described above. 
     In summary, the improved security system of the present invention provides a system which can be used in numerous retail establishments, which utilizes a smart key as the main component, which even if stolen, cannot be used even in the store of its origin after a predetermined time period to disarm an alarm module, and can never be used in another store to disarm a security device since it is programmed with a SDC unique to that particular store, and that the SDC is initially randomly generated by a programming station used only by that store. The smart key contains an internal timer which will deactivate a validly stored SDC after a predetermined time period thereby rendering the key completely useless even in the store of its origin after this time period. The key has to be taken back to the programming station which can be maintained in a secure location enabling an authorized clerk to reprogram the key with the same SDC for subsequent use with the various alarm modules in the store, all of which will have been programmed from one of the smart keys with the unique SDC for that store. Also, programming station  3 , smart key  5  and alarm module  7  each have various types of visual indicators and/or alarms which advise a store clerk of the status of these components, and which will alert the clerk if an item of merchandise and/or alarm module is being tampered with. Also, programming station  3  will deactivate a stored SDC in a key if it is the wrong SDC when attempting to reprogram the key at programming station  3 . Also alarm module  7  will sound an alarm if a key containing a wrong SDC is attempted to be used on the alarm module. In addition to these features, each of the individual components have various timing circuits, control circuits and visual indicating circuits all of which are part of the internal logic control circuits contained in the components, which features are described in further detail in the above-referenced related patent applications covering each of these components. 
     Another feature which may be incorporated into the present invention is the use of a “master” key and “employee” keys in order to provide an additional layer of security to the security system of a particular retail store. In this dual key system, the random number generator contained in the logic control circuit of the programming station will only generate the SDC when the master key is presented to the station and a limited access switch is activated. This master key then can be used to program the SDC into the various alarm modules, as well as the employee keys which are subsequently programmed with the SDC by the programming station once the SDC is generated by using the master key. 
     The use of the master key enables the store manager to change the SDC of the programming station which then is subsequently used by the employee keys and the alarm modules throughout the store, if for some reason the manager believes that the original SDC was compromised. Should a new SDC be generated by the master key and then reprogrammed into the employee keys, the control logic circuit of the alarm module will be provided with a means of recognizing both the old and the new SDC of a key when in wireless communication therewith. This will enable the alarm module to accept the new SDC to disarm the alarm module without activating the audible alarm, which would occur as discussed above when the alarm module reads the use of a key having a wrong SDC programmed therein. 
     This dual key system would increase the complexity of the various logic control circuits in the smart keys, programming station and alarm modules, but would provide an additional layer of security should the location using the improved security system of the present invention desire such an increased level of security. However, the preferred embodiment described previously is believed to provide adequate security protection for a merchandise system by the use of only a single key. However, the dual key system can be used without departing from the concept of the present invention. 
     Although the above description refers to the security code being a disarm code, it is understood that the code can activate and control other functions and features of the security device such as unlocking the device from the product, shutting off an alarm etc. without departing from the concept of the invention. Likewise, the various components of the logic circuit and resulting flow charts can easily be modified by one skilled in the art to achieve the same results. Also, the security code can be preset in the programming station at the factory or chosen by the customer, and if desired, be changed later by the customer, also without affecting the concept of the invention. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
     Moreover, the description and illustration of a preferred embodiment of the invention is an example and the invention is not limited to the exact details shown or described.