Abstract:
A method of message management is provided for use with a mobile communications device having core and protected memories. The mobile communications device is in communication with a radio telecommunications system comprised of authorized and unauthorized radio telecommunications system operators, each operator have a unique identification code which is associated with messages communicated therefrom. The method of message management includes the step of storing the identification code of the authorized system operator in the core memory, receiving a message with an identification code associated therewith from the radio telecommunications system, and comparing the identification code of the message with the identification code of the authorized system operator. The method further includes the step of storing the message in the protected memory only if the identification code of the message matches the identification code of the authorized system operator. An apparatus is also provided for practicing the above mentioned method.

Description:
FIELD OF THE INVENTION 
     This invention is directed to a security system and a method for securing communications between a mobile communications device and one of a plurality of radio telecommunications service providers, and in particular, to a security system and a method for securing communications wherein messages from the one of the plurality of radio telecommunications service providers has a unique identification code associated therewith which is provided to the mobile communications device. 
     BACKGROUND OF THE INVENTION 
     In this age of radio telecommunications, one of the most important radio telecommunications devices is the mobile or cellular phone. At the present time, it is common for cellular phone service providers or system operators to offer significant bargains on the purchase of a cellular phone to encourage customers to sign up or subscribe to their cellular phone service for a fixed period of time. For example, it is not uncommon for cellular phone service providers to offer free cellular phones to prospective subscribers. 
     It is therefore of significant concern to cellular phone service providers that the cellular phones which they offer as a premium not be programmable for use with a competitor&#39;s cellular phone service until the service period of the contract has elapsed so as to allow the provider to recapture the cost of the phone. If the cellular phones could be easily reprogrammed to recognize and be used with a competitor&#39;s service, those system operators offering no or low cost cellular phones would lose a significant economic investment to service providers who choose not to offer premium pricing on cellular phones. As a consequence, it is presently highly desirable to provide some type of security measure to prevent the reprogramming of cellular phones. 
     One way in which a cellular phone can be protected against reprogramming is by “hard-coding” key or core service provider information into the cellular phone such that the phone only recognizes messages from the system operator which provides the phone, also referred to as the home system operator. Hard-coding refers to a parameter whose value is not variable, but is determined at the time a software program is written. Such hard coding would occur at the factory as the manufacture of the mobile phone is completed. 
     This solution is a rather extreme security measure. Hard-coding core information into a phone presents the same inflexibility to modification to the home system operator&#39;s programmer that it would to a competitor&#39;s programmer. To implement changes in the core information, it would be necessary to rewrite not just individual parameter values, but the software itself. This can result in significant hindrances in updating the core information. 
     Furthermore, it is now known in the art to provide over-the-air teleservices. An over-the-air teleservice is a service wherein the remote programming of cellular phones is achieved through the use of radio frequency messages. 
     There are two specific over-the-air teleservices which are coming into widespread use in the industry. The first teleservice is known as an over-the-air activation teleservice (OATS), and the second is known as an over-the-air programming teleservice (OPTS). Through OATS, a system operator can download core information to the mobile phone to configure the phone to be compatible with the system operator&#39;s service. Through OPTS, a system operator can, for example, download information on partner, favored, and forbidden radio telecommunications systems, which information may then be used by the cellular phone in selecting a service from the radio telecommunications systems. 
     These over-the-air teleservices provide the radio telecommunications system operators with greater flexibility in tailoring cellular phones to meet the needs of their subscribers. It would not be possible to use these, however, if the phones had been hard-coded to prevent overwrites. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the invention, a method of message management is provided for use with a mobile communications device having a core memory and a protected memory. The mobile communications device is in communication with a radio telecommunications system comprised of an authorized radio telecommunications system operator and an unauthorized radio telecommunications system operator. The authorized and unauthorized radio telecommunications system operators each have a unique identification code which is associated with messages communicated therefrom. The method of message management includes the step of storing the identification code of the authorized radio telecommunications system operator in the core memory. The method further includes the steps of receiving a message with an identification code associated therewith from the radio telecommunications system, and comparing the identification code of the message with the identification code of the authorized radio telecommunications system stored in the core memory if the message is to be stored in the protected memory. The method further includes the step of storing the message in the protected memory only if the identification code of the message matches the identification code of the authorized radio telecommunications system operator stored in the core memory. 
     Moreover, the method may include the step of transmitting a reject-message signal to the radio telecommunications system if the message is not stored in the protected memory. 
     Moreover, wherein the mobile communications device has an unprotected memory, the method may include the steps of determining if the message is to be stored in the protected memory or the unprotected memory, and storing the message in the unprotected memory if the message is to be stored in the unprotected memory. The method may also include the step of transmitting an accept-message signal to the radio telecommunications system if the message is stored either in the protected memory or the unprotected memory. 
     Moreover, the message may be an over-the-air-activation message and the identification code associated with the message may be a system operator code identifying an authorized or an unauthorized radio telecommunications system operator. 
     Moreover, the message may be an over-the-air-programming message having information regarding the bands of the authorized and unauthorized radio telecommunications service providers and the identification code associated with the message are the values of a predetermined sequence of bands representative of an authorized or an unauthorized radio telecommunications system operator. 
     In another aspect of the invention, a mobile communications device is provided for use with a radio telecommunications system. The radio telecommunications system includes an authorized radio telecommunications system operator and an unauthorized radio telecommunications system operator. The authorized and unauthorized radio telecommunications system operators each have a unique identification code which is associated with messages communicated therefrom. The mobile communications device includes a receiver to receive messages from a radio telecommunications network. The device also includes a core memory with an identification code stored therein, the identification code associated with an authorized radio telecommunications system operator, a protected memory, and a programmable computational apparatus coupled to the receiver and the core memory. The mobile communications device further has a message management program operating in the programmable computational apparatus, wherein the message management program controls the programmable computational apparatus to compare an identification code of a message received by the receiver with the identification code of the authorized radio telecommunications system operator stored in the core memory if the message is to be stored in the protected memory. The message management program also operates in the programmable computational apparatus to store the message in the protected memory only if the identification code of the message matches the identification code of the authorized radio telecommunications system operator stored in the core memory. 
     Moreover, the mobile communications device may have an unprotected memory, wherein the message management program controls the programmable computational apparatus to determine if a message is to be stored in the protected memory or the unprotected memory. The message management program also controls the programmable computational apparatus to store the message in the unprotected memory if the programmable computational apparatus determines that the message is to be stored in the unprotected memory. The mobile communications device may also have a transmitter to transmit an accept-message signal to the telecommunications system, wherein the data management program controls the programmable computational apparatus to provide an accept-message signal to the transmitter if the message is stored in either the protected or unprotected memories. 
     Moreover, the message may be an over-the-air-activation message. The protected memory may contain a site for storing over-the-air activation messages. 
     Moreover, the message may be an over-the-air-programming message having information regarding the bands of the authorized and unauthorized radio telecommunications service providers. The protected memory may contain a site for storing over-the-air programming messages. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic representation of a radio telecommunications system including a plurality of radio telecommunications service providers in communication with a mobile communications device; 
     FIG. 2 is a block diagram of a mobile station or mobile communications device according to an embodiment of the present invention having a protected, permanent memory; 
     FIG. 3 is a block diagram of a mobile station or mobile communications device according to a further embodiment of the present invention having a permanent memory with protected and unprotected sections; 
     FIG. 4 is a flow chart illustrating a program according to an embodiment of the present invention for allowing only over-the-air activation messages from an authorized radio telecommunications service provider to be written into a protected memory of a mobile station or mobile communications device while rejecting other messages; 
     FIG. 5 is a flow chart illustrating a program according to a further embodiment of the present invention for allowing only over-the-air programming messages from an authorized radio telecommunications service provider to be written into a protected memory of a mobile station or mobile communications device while rejecting other messages; and 
     FIG. 6 is a flow chart illustrating a program according to a still further embodiment of the present invention for allowing messages from an authorized radio telecommunications service provider to be written into a protected memory of a mobile station or mobile communications device and messages from either authorized or unauthorized service providers to be written into an unprotected memory. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIG. 1, a radio telecommunications system  10  is shown. Within the radio telecommunications system  10  are a plurality of radio telecommunications service providers  12 ,  14 ,  16 . Each of the service providers  12 ,  14 ,  16  may operate one or more radio telecommunications networks, each network being represented by a cell cluster. Each cell cluster has, in turn, a plurality of cells, each cell having base station represented by an antenna. 
     For example, as shown in FIG. 1, the service provider  12  has two radio telecommunications networks  18 ,  20 , the network  18  having base stations  22 ,  24 ,  26 ,  28 ,  30 ,  32 ,  34  and the network  20  having base stations  36 ,  38 ,  40 ,  42 ,  44 ,  46 ,  48 . Similarly, the service provider has three radio telecommunications networks  50 ,  52 ,  54 , the network  50  having base stations  56 ,  58 ,  60 ,  62 ,  64 ,  66 ,  68 , the network  52  having base stations  70 ,  72 ,  74 ,  76 ,  78 ,  80 ,  82  and the network  54  having base stations  84 ,  86 ,  88 ,  90 ,  92 ,  94 ,  96 . Further, the service provider  16  has a network  98  with base stations  100 ,  102 ,  104 ,  106 ,  108 ,  110 ,  112 . 
     While each of the radio telecommunications networks  18 ,  20 ,  50 ,  52 ,  54 ,  98  is shown separated spatially from the other radio telecommunications networks, it should be recognized that one radio telecommunications network, for example the radio telecommunications system  18 , may overlap geographically with another radio telecommunications network, such as the radio telecommunications network  50 . By way of example, a coverage area  114  of the base station  26  may overlap, in whole or in part, with a coverage area  116  of the base station  66 . 
     It should also be recognized that messages transmitted by the service providers may be structured data messages, such as over-the-air activation messages or over-the-air programming messages, but that the messages referred to herein encompass any transmission of information in any form by the service providers. 
     It should further be recognized that the messages transmitted from the base stations within a predetermined telecommunications network of a predetermined service provider typically have identification codes associated therewith which are unique to the network and to the service provider. A message, represented by an arrow  118 , transmitted from the base station  48  has one or more identification codes associated therewith which identify the message  118  as originating from within the network  20  and the service provider  12 . Similarly, a message, represented by an arrow  120 , has codes associated therewith identifying the network  52  and the service provider  14 , and a message, represented by an arrow  122 , has codes associated therewith identifying the network  98  and the service provider  16 . 
     In the case of an over-the-air activation message, the code which can be used to identify the messages of a service provider with that service provider is known as a system operator code (SOC). In the case of an over-the-air programming message, and in particular an over-the-air programming message for use in selecting a service provider from among partner, favored and forbidden service providers, the specific service provider can be identified by the bands associated with the service provider which are used by the networks of that service provider across its coverage area. For example, for the service provider  12 , the network  18  may use specific cellular bands a and b, and Personal Communications Service (PCS) bands A and C, while the network  20  may use the same cellular bands a, b and PCS band A, but PCS band D rather than band C because of an agreement reached with the service provider  14 . In this case, messages from the networks  18  and  20  of the service provider  12  can be identified through the specific cellular bands a, b and PCS band A. 
     Also shown in FIG. 1 is a mobile station or mobile communications device  124 . A first embodiment of the mobile communications device  124  is shown in greater detail in FIG.  2 . The mobile communications device has an antenna  126  and a transmitter/receiver assembly  128  coupled thereto to receive messages  118 ,  120 ,  122  from the service providers  12 ,  14 ,  16 . The messages  118 ,  120 ,  122  are transferrable from the transmitter/receiver assembly  128  to a data bus  130 . 
     The mobile communications device  124  also has a programmable computational apparatus  132 , a permanent (i.e. non-volatile) memory  134 , and a core memory  136 . The programmable computational apparatus  132  is used, according to the method of the present invention, to selectively control which of the messages  118 ,  120 ,  122  may be stored in the permanent memory  134 . 
     The mobile communications device  124  also has a program which operates the programmable computational apparatus  132  to make a comparison between an identification code associated with the messages  118 ,  120 ,  122  and an identification code stored in the core memory  136  representative of a home system or service provider, such as the service provider  12 . If it is determined that the identification code received with the message  118 , for example, matches the identification code stored in the core memory  134  for the home system or service provider  12  (which in this case it does), then the message  118  is stored in the permanent memory  134  under the control of the programmable computational device  132 . 
     The structure and operation of the first embodiment of the present invention is now discussed in greater detail. In addition to the antenna  126 , the transmitter/receiver  128 , the programmable computational apparatus  132 , the data bus  130 , the permanent memory  134 , and the core memory  136 , the mobile communications device  124  includes a temporary (volatile) memory  138  and an input-output assembly  140 . The data bus  130  is connected to the transmitter/receiver  128 , the programmable computational device  132 , the temporary memory  138 , the permanent memory  134 , the core memory  136  and the input-output assembly  140  as shown in FIG. 2 so that data can be transferred between these elements in accordance with a program operating in the programmable computational apparatus  132 . The program operates the programmable computational apparatus  132  as shown in FIGS. 4 and 5. 
     FIG. 4 illustrates a program according to the present invention for preventing an over-the-air activation teleservice (OATS) message sent by an unauthorized radio telecommunications system from being stored in the permanent memory  134 . At block  142 , a message is received by the mobile communications device  124  from one of the radio telecommunications service providers of the radio telecommunications system  10 . At block  144 , the OATS message received by the mobile telecommunications device  124  is stored in the temporary memory  138 . At block  146 , the programmable computational apparatus  132  determines whether the permanent memory  134  is code-protected, i.e. whether the security system is activated. According to the present invention, the security system may be activated by the service provider when the mobile communications device  124  is assembled and programmed, or later by the service provider when the mobile communications device is provided to the subscriber, or may even be an option which the subscriber may select through the use of the input-output assembly  140 . 
     If the programmable computational apparatus  132  determines at block  146  that the code-protection has not been selected, then at block  148  the programmable computational apparatus  132  allows the message stored in the temporary memory  138  to be stored in the memory  134 . The programmable computational apparatus  132  then sends at block  150  an accept-message signal via the antenna  126  and the transmitter/receiver assembly  128  to the radio telecommunications network  10  indicating that the message which the mobile communications device  124  received has been stored in the permanent memory  134 . 
     Alternatively, if the programmable computational apparatus  132  determines that the permanent memory  134  is code-protected at block  146 , then the programmable computational apparatus  132  accesses the temporary memory  138  and the core memory  136 . As the message received was an OATS message, the programmable computational device  132  retrieves the system operator code (SOC) associated with the data message stored in temporary memory  138  and compares it with the SOC for the home system stored in the core memory  136 . 
     If the SOC associated with the message stored. in the temporary memory  138  matches the SOC stored in the core memory  136 , then the programmable computational apparatus  132  allows the message stored in the temporary memory  138  to be transferred to and stored in the permanent memory  134  at block  148 . At block  150 , an accept-message signal is then sent as before. 
     If, however, the SOC associated with the message stored in the temporary memory  138  does not match the SOC stored in the core memory  136 , then at block  154  the programmable computational apparatus  132  allows the message to be discarded. That is, the message is not transferred and stored in permanent memory  134 , but may be allowed to remain in the temporary memory  138  until the message is overwritten, or the mobile communications device  124  is turned off. If the data message is to be discarded at block  154 , then at block  156  the programmable computational apparatus  132  sends a signal via the antenna  126  and transmitter/receiver assembly  128  to the radio telecommunications network  10  that the message was rejected. 
     FIG. 5 illustrates a program according to the present invention for preventing an over-the-air programming teleservice (OPTS) message (in particular an over-the-air programming message for use in selecting a service provider from among partner, favored and forbidden service providers) sent by an unauthorized radio telecommunications system from being stored in the protected memory  134 . At block  158 , an OPTS message is received by the mobile communications device from one of the radio telecommunications service providers of the radio telecommunications system  10 . At block  160 , the OPTS message received by the mobile telecommunications device  124  is stored in the temporary memory  138 . At block  162 , the programmable computational apparatus  132  determines whether the permanent memory  134  is code-protected, i.e. whether the security system is activated. According to the present invention, the security system may be activated by the service provider when the mobile communications device  124  is assembled and programmed, or later by the service provider when the mobile communications device  124  is provided to the subscriber, or may even be an option which the subscriber may select through the use of the input-output assembly  140 . 
     If the programmable computational apparatus  132  determines at block  162  that the code-protection has not been selected, then at block  164  the programmable computational apparatus  132  allows the message stored in the temporary memory  138  to be stored in the permanent memory  134 . The programmable computational apparatus  132  then sends at block  166  an accept-message signal via the antenna  126  and the transmitter/receiver assembly  128  to the radio telecommunications network  10  indicating that the message which the mobile communications device  124  received has been stored in the permanent memory  134 . 
     Alternatively, if the programmable computational apparatus  132  determines that the permanent memory  134  is code-protected at block  162 , then the programmable computational apparatus  132  accesses the temporary memory  138  and the core memory  136 . As the message received was an OPTS message, the programmable computational device  132  retrieves the values of a predetermined sequence of bands associated with the data message stored in temporary memory  138  and compares them with the values for the predetermined sequence of bands associated with the home system throughout the home system coverage area which were stored in the core memory  136 . As indicated above, the predetermined sequence of bands may be selected from cellular a, cellular b, and PCS A-F. Most preferably, the predetermined sequence of bands is made up of three bands, in particular the cellular a, cellular b, and PCS A bands. 
     If the values of the predetermined sequence of bands associated with the message stored in the temporary memory  138  match the values for the predetermined sequence of bands stored in the core memory  136 , then the programmable computational apparatus  132  allows the message stored in the temporary memory  138  to be transferred to and stored in the permanent memory  134  at block  164 . An accept signal message is then sent at block  166 . 
     If, however, the values for the bands associated with the message stored in the temporary memory  138  do not match the values of the bands stored in the core memory  136 , then at block  170  the programmable computational apparatus  132  allows the message to be discarded. If the data message is to be discarded at block  170 , then at block  172  the programmable computational apparatus  132  sends a signal via the antenna  126  and transmitter/receiver assembly  128  to the radio telecommunications network  10  that the message was rejected. 
     Having discussed code-protection for both OATS and OPTS messages, it should be recognized that the mobile communications device  124  may have code-protection for both OATS and OPTS messages, either OATS or OPTS messages, or neither OATS nor OPTS messages. Moreover, it should also be recognized that while the discussion above highlights the utility of the present invention with respect to messages transmitted from radio telecommunications service providers to the mobile communications device  124  over-the-air, the security method according to the present invention could be used with messages that are received from the radio telecommunications service providers, for example, through the input/output assembly  140 . For example, messages could be communicated to the mobile communications device  124  by attaching a cable to the data bus  130  of the mobile communications device  124  via the input/output assembly  140  and downloading thereby messages from the radio telecommunications service provider stored, for example, in a data storage apparatus in a form readable by the programmable computational apparatus  132 . 
     The system and method according to the present invention are now discussed with reference to messages  118 ,  120 , the security system being activated, the messages  118 ,  120  being OATS messages, the service provider  12  being the home system operator and service provider  14  being a competitor. First, the message  118  is received by the mobile communications device  124  from the radio telecommunications service provider  12  at block  142 . At block  144 , the OATS message  118  is stored in the temporary memory  138 . 
     At block  146 , the programmable computational apparatus  132  determines whether the protected memory is code-protected, i.e. whether the security system is activated. As the security system has been activated, then the programmable computational apparatus  132  accesses the temporary memory  138  and the core memory  136  at block  152 . The programmable computational device  132  retrieves the system operator code (SOC) associated with the data message  118  and compares it with the SOC for the home system operator  12  stored in the core memory  136 . As the SOC associated with the message stored in the temporary memory  138  matches the SOC stored in the core memory  136 , the programmable computational apparatus  132  allows the message  118  stored in the temporary memory  138  to be transferred to and stored in the permanent memory  134  at block  148 . An accept-message signal (block  150 ) is sent. 
     Alternatively, if the message  120  was received, then program would follow the same steps of storing the message  120  in temporary memory  138  (block  144 ), checking to see that the security system is activated (block  146 ), and comparing the SOC codes (block  152 ). However, as the SOC associated with the message  120  does not match the SOC stored in the core memory  136 , then at block  154  the programmable computational apparatus  132  allows the message  120  to be discarded. At block  156 , the programmable computational apparatus  132  sends a signal via the antenna  126  and transmitter/receiver assembly  128  to the radio telecommunications network  10  that the message was rejected. 
     Alternatively, the system and method according to the present invention may be discussed with reference to messages  118 ,  120 , the security system being activated, the messages  118  and  120  being OPTS messages, the service provider  12  being the home system operator and service provider  14  being a competitor. First, the message  118  is received by the mobile communications device  124  from the radio telecommunications service provider  12  at block  158 . At block  160 , the OPTS message  118  is stored in the temporary memory  138 . 
     At block  162 , the programmable computational apparatus  132  determines whether the protected memory is code-protected, i.e. whether the security system is activated. As the security system has been activated, then the programmable computational apparatus  132  accesses the temporary memory  138  and the core memory  136  at block  168 . The programmable computational device  132  retrieves the values for a predetermined sequence of bands associated with the data message  118  and compares them with the values for the predetermined sequence of bands for the home system operator  12  stored in the core memory  136 . As the values of the bands associated with the message stored in the temporary memory  138  match the values for the bands stored in the core memory  136 , the programmable computational apparatus  132  allows the message  118  stored in the temporary memory  138  to be transferred to and stored in the permanent memory  134  at block  164 . An accept message signal is sent at block  166 . 
     Alternatively, if the message  120  was received, then the program would follow the same steps of storing the message  120  in temporary memory  138  (block  160 ), checking to see that the security system is activated (block  162 ), and comparing the band values (block  168 ). However, as the values of the predetermined sequence of bands associated with the message  120  do not match the values of values of the predetermined sequence of bands the stored in the core memory  136 , then at block  170  the programmable computational apparatus  132  allows the message to be discarded. At block  172 , the programmable computational apparatus  132  sends a signal via the antenna  126  and transmitter/receiver assembly  128  to the radio telecommunications network  10  that the message was rejected. 
     As still further alternative, wherein the message  122  is received from a competitor service provider  16  and the permanent memory  134  is not code-protected for either OATS messages or OPTS messages, the programs would follow the same steps of storing the message (block  144  or block  160 ) and checking to see if the permanent memory was code-protected (block  146  or  162 ). However, finding that the permanent memory  134  was not code-protected, the program would allow the data message to be stored in the permanent memory  134  (block  148  or  164 ) and send an accept-message signal (block  150  or  166 ). 
     According to another embodiment of the present invention, as shown in FIG. 3, the mobile communications device includes an antenna  174 , a transmitter/receiver assembly  176 , a data bus  178 , a programmable computational apparatus  180 , a temporary memory  182 , a permanent memory  184  with an unprotected section  186  and a protected section  188 , a core memory  190 , and an input-output assembly  192 . The transmitter/receiver assembly  176 , the programmable computational apparatus  180 , the temporary memory  182 , the permanent memory  184 , the core memory  190 , and the input-output assembly  192  are connected to the data bus  178  so that data can be transferred between these elements in accordance with a program operating in the programmable computational apparatus  180  which operates the programmable computational apparatus  180  as shown in FIG.  6 . 
     The program illustrated in the flow chart of FIG. 6 is substantially similar to either of the programs shown in FIGS. 4 and 5. At block  194 , a message is received by the mobile communications device  124 . The message is stored in the temporary memory  182  at block  196 . 
     Because the permanent memory  184  of the mobile communications device  124  shown in FIG. 3 is divided into unprotected and protected sections, i.e. some sections of the memory  184  are not subject to code-protection, the programmable computational device determines at block  198  whether the message is addressed to go to the unprotected memory  186  or the protected memory  188 . If the message is addressed to the unprotected memory  186 , then the programmable computational device  180  transfers the message from the temporary memory  182  to the permanent memory  184  at block  200 . An accept-message signal is then sent at block  202 . 
     If, however, it is determined that the message is addressed to the protected memory  188  of the permanent memory  184 , then the programmable computational apparatus  180  checks to see if the code-protection has been activated at block  204 . As described above, if the programmable computational apparatus  180  determines that the code-protection is not activated, then the message is stored in the protected memory section  188  of the permanent memory  184  (block  200 ) and the accept-message signal is sent (block  202 ). 
     If it is determined at block  204  that the protected memory section  188  is code-protected, then at block  206  the programmable computation device  180  accesses the temporary memory  182  and the core memory  190 , retrieves the codes associated with the message and the home system operator (whether those are SOC codes for OATS messages, values of a predetermined sequences of bands for OPTS messages, or some other code), and determines if the codes match. If the codes match, then the message is transferred from the temporary memory  182  to the permanent memory  184  at block  200 . If the codes do not match, then the message is discarded at block  208  and the reject-message signal is communicated at block  210  to the radio telecommunications system  10 . 
     Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims.