Abstract:
When receiving an incoming call to the previous phone number, adequacy of notification is determined on the basis of history data relating to a caller number and a previous phone number. The method includes: acquiring a caller number and a destination number upon receipt of a request for connecting to a specific destination number, acquiring history data relating to the destination number and caller number from history data storage, analyzing the acquired history data in accordance with preset notification adequacy determination rules to determine whether to provide notification of the new phone number, and transmitting notification data.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The present invention relates to a communication service. In particular, the present invention relates to a method for providing notification of a change of a phone number or a phone mail address. 
         [0003]    2. Description of the Related Art 
         [0004]    The notification of a change of a phone number is required to be provided to acquaintances of a cell phone user when the user changes his or her cell phone number. Instead of users notifying their acquaintances of new phone numbers, phone number change notification services have been provided by telephone service companies since the age of fixed telephones, where phone number change notification systems provide new phone numbers to all incoming calls to previous phone numbers. Also, such measures are considered that a phone number change notification system does not provide a new phone number to incoming calls from specific caller numbers or that a phone number change notification system provides a new phone number to incoming calls from specific caller numbers. These are efforts to limit targets to be notified of a phone number as personal information for the purposes of privacy protection, antistalking, prank call prevention, and the like. 
         [0005]    Japanese Laid-open Patent Publication No. 2005-328313 discusses a technology for causing a phone number change notification system to provide a new phone number to incoming calls from specific caller numbers. 
         [0006]    In order for the system of the cell phone service company to provide the new phone number to incoming calls from the specific caller numbers, the phone number changer (the person who changes his or her phone number) is required to previously register the phone numbers of targets to be notified of the new phone number. For this reason, the phone number changer uses the address book function of his or her cell phone, that is, the phone number changer selects the phone numbers of targets to be notified of the new phone number from among phone numbers included in the address book, and then registers the selected phone numbers in the system of the cell phone service company. 
         [0007]    However, if a lot of phone numbers are included in the address book, it is troublesome work for the phone number changer to determine, for each of the phone numbers, adequacy of notification of the new phone number so as to register adequate phone numbers. Also, if the phone number changer repurchases a cell phone due to the loss of his or her cell phone and thus changes the previous phone number, the phone number changer cannot use the address book function of the previous cell phone since he or she no longer has the previous cell phone at hand. Therefore, it is difficult for the phone number changer to specify the phone numbers of targets to be notified of his or her new phone number. This also applies to cases where a phone mail address is changed. 
       SUMMARY 
       [0008]    An object of the present invention is to provide an identifier change notification method by which when providing notification of the change of a communication identifier such as a phone number or a phone mail address, an identifier change notification apparatus notifies appropriate targets of a new identifier without the identifier changer (the person who changes his or her identifier for communication) previously specifying the communication identifiers of targets to be notified of the new identifier. 
         [0009]    According to an aspect of the present invention, provided is an identifier change notification method for notifying a communication device of a change of a communication identifier. An information processing apparatus includes a data storage storing a previous identifier, a new identifier, and history data. The method includes: acquiring a source identifier and a destination identifier from incoming data, acquiring history data relating to both the previous identifier and the source identifier if the destination identifier matches the previous identifier, determining adequacy of notifying the communication device of the new identifier, and transmitting the new identifier to the communication device. 
         [0010]    The communication identifier may be a phone number or a phone mail address. 
         [0011]    The method may further include: acquiring the previous identifier if the destination identifier matches the new identifier, acquiring history data relating to both the previous identifier and the source identifier if the destination identifier matches the new identifier, and refusing transfer of the incoming data if the determined adequacy indicates that notification is inadequate. 
         [0012]    The method may further include: acquiring the previous identifier if the destination identifier matches the new identifier, refusing transfer of the incoming data if the data storage has refusal data indicating that notification is inadequate with respect to the source identifier, and storing the refusal data in the data storage if the determined adequacy indicates that notification is inadequate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a diagram illustrating relations between phones and communication servers in a description of an identifier change notification method according to a first embodiment of the present invention; 
           [0014]      FIG. 2  is a diagram illustrating an example configuration of number notification data according to a first embodiment of the present invention; 
           [0015]      FIG. 3  is a diagram illustrating examples of notification adequacy determination rules according to a first embodiment of the present invention; 
           [0016]      FIG. 4  is a diagram illustrating an example configuration of history data according to a first embodiment of the present invention; 
           [0017]      FIG. 5  is a block diagram illustrating an outline configuration of a first communication server executing an identifier change notification method according to a first embodiment of the present invention; 
           [0018]      FIG. 6  is a flowchart illustrating a processing flow of a first communication server executing an identifier change notification method according to a first embodiment of the present invention; 
           [0019]      FIG. 7  is a flowchart illustrating a processing flow of a first communication server according to a first embodiment of the present invention when receiving an incoming call to a new phone number; 
           [0020]      FIG. 8  is a flowchart illustrating a processing flow of a first communication server according to a first embodiment of the present invention when receiving an incoming call to a new phone number; 
           [0021]      FIG. 9  is a diagram illustrating relations between phones and communication servers in a description of an identifier change notification method according to a second embodiment of the present invention; 
           [0022]      FIG. 10  is a diagram illustrating an example configuration of address notification data according to a second embodiment of the present invention; 
           [0023]      FIG. 11  is a diagram illustrating examples of notification adequacy determination rules according to a second embodiment of the present invention; 
           [0024]      FIG. 12  is a diagram illustrating an example configuration of history data according to a second embodiment of the present invention; 
           [0025]      FIG. 13  is a block diagram illustrating an outline configuration of a first communication server executing an identifier change notification method according to a second embodiment of the present invention; 
           [0026]      FIG. 14  is a flowchart illustrating a processing flow of a first communication server executing an identifier change notification method according to a second embodiment of the present invention; 
           [0027]      FIG. 15  is a flowchart illustrating a processing flow of a first communication server according to a second embodiment of the present invention when receiving a phone mail to a new phone mail address; 
           [0028]      FIG. 16  is a flowchart illustrating a processing flow of a first communication server according to a second embodiment of the present invention when receiving an incoming phone mail to a new phone mail address; and 
           [0029]      FIG. 17  is a diagram illustrating an example of a computer environment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    According to aspects of the present invention, an identifier change notification apparatus determines whether to provide notification of a new identifier of a destination (that is, the identifier changer) to a source, on the basis of history data of communications relating to the communication identifier of the source and the previous identifier of the destination. 
         [0031]    The previous identifier of the identifier changer is registered as a target of the identifier change notification process, and history data regarding the previous identifier is recorded. Also, notification data including the new identifier is registered in association with the previous identifier. 
         [0032]    When an acquaintance of the identifier changer makes a transmission to the previous identifier of the identifier changer, the identifier change notification apparatus receives the transmission. The identifier change notification apparatus acquires the communication identifier of the acquaintance as the source identifier and the previous identifier of the identifier changer as the destination identifier. The identifier change notification apparatus also acquires history data including the source identifier as the counterpart identifier from history data regarding the destination identifier. Then, the identifier change notification apparatus determines whether to provide identifier change notification according to rules previously set. 
         [0033]    The identifier change notification apparatus determines whether to provide identifier change notification on the basis of the history data. Thus, the identifier change notification apparatus may notify appropriate targets of the new identifier even if the identifier changer does not previously specify the communication identifiers of the targets to which notification of the new identifier is to be provided. 
       First Embodiment 
       [0034]    Referring now to  FIGS. 1 to 8 , an identifier change notification method according to a first embodiment of the present invention will be described. The first embodiment of the present invention allows notification of the change of a phone number.  FIG. 1  is a diagram illustrating relations between phones and communication servers in a description of an identifier change notification method according to a first embodiment of the present invention. 
         [0035]    A phone number changer  100  loses a first phone  104  controlled by a first communication server  102  and then uses a second phone  106  controlled by the same server. Accordingly, the phone number changer  100  is required to provide notification of a new phone number for identifying the second phone  106 , to acquaintances who know only the previous phone number for identifying the first phone  104 . The first communication server  102  stores history data relating to phones under its control in history data storage  108 . The phone number changer  100  sets rules for determining whether to provide notification of the new phone number on the basis of the history data stored in the history data storage  108 . These rules are contained in number notification data stored in number notification data storage  110  of the first communication server  102 . The phones and communication servers shown in  FIG. 1  may communicate with one another over communication networks  116 ,  118 , and  120 . 
         [0036]      FIG. 2  is a diagram illustrating an example configuration of number notification data according to a first embodiment of the present invention. A customer ID (identifier)  202  is data for uniquely identifying the phone number changer  100 . A previous phone number  204  is a phone number of the phone number changer  100  before a phone number change is made, and serves as a destination number when receiving incoming calls from acquaintances of the phone number changer  100 . A new phone number  206  is a phone number of the phone number changer  100  after the phone number change is made and serves as a main part of number notification data when a phone number change notification is provided. Notification adequacy determination rules  208  will be described later. A notification start date  210  is the start date of a phone number change notification service. A notification end date  212  is the end date of the phone number change notification service. The configuration of the number notification data stored in the number notification data storage  110  is not limited to the configuration shown in  FIG. 2  and may be any configuration as long as the number notification data stored in the number notification data storage  110  includes the previous phone number  204 , new phone number  206 , and notification adequacy determination rules  208 . 
         [0037]      FIG. 3  is a diagram illustrating examples of notification adequacy determination rules according to a first embodiment of the present invention. Each rule record contains a rule ID  252  identifiable of the rule, a notification adequacy  254  indicating a determination result, and conditions for determination. In this example, adequacy of notification is determined on the basis of an incoming call count  258 , an outgoing call count  260 , or a conversation count  262  during a target period  256  contained in the history data stored in the history data storage  108 . Any blank item in  FIG. 3  indicates that no condition is set for the blank item. A rule_ 11  indicates that the new phone number  206  will not be provided to a target to which no call has been made during the last 30 days according to the history data stored in the history data storage  108 . A rule_ 12  indicates that the new phone number  206  will not be provided to a target from which no incoming call has been received and with which no phone conversation has been held during the last 10 days according to the history data stored in the history data storage  108 . A rule_ 13  indicates that the new phone number  206  will not be provided to a target from which more than ten incoming calls have been received and to which no call has been made through the entire period of time according to the history data stored in the history data storage  108 . The phone number changer  100  defines rules in such manners. Accordingly, notification of the new phone number  206  is provided to targets that do not satisfy the conditions set under these rules. The rules shown in  FIG. 3  are applicable as long as the history data stored in the history data storage  108  includes, for example, data on the date &amp; time of incoming calls, date &amp; time of outgoing calls, and whether a phone conversation has been held. The notification adequacy determination rules  208  are not limited to what are shown in  FIG. 3  and any arbitrary rule may be set on the basis of data on the count or frequency of incoming/outgoing calls, a phone conversation time, an hour of day of incoming/outgoing calls, a time period between the time when a call reception request has arrived and the time when the request is cancelled, an operation for refusing call reception, or the like obtained from the history data stored in the history data storage  108 . In addition to rules based on the history data stored in the history data storage  108 , rules based on data on the current incoming call may be set. Such rules may include a rule based on the time of the all reception, the absence of notification of a caller number, a call from a public phone, a caller number registered to an incoming call refusal list, or the like. 
         [0038]      FIG. 4  is a diagram illustrating an example configuration of history data according to a first embodiment of the present invention. A customer phone number  214  is a phone number controlled by the first communication server  102 . For the sake of convenience, it is assumed that the history data storage  108  stores history data relating to the previous phone number of only a customer requesting the phone number change notification service. A counterpart phone number  216  is a phone number of a counterpart which the customer identified with the customer phone number  214  has had incoming/outgoing calls with. An incoming date &amp; time  218  is data indicating the date and time of when the incoming call has been received. An outgoing date &amp; time  220  is data indicating the date and time of when the outgoing call has been made. A conversation time  222  is data indicating the length of a time during which a phone conversation has been held. The configuration of the history data stored in the history data storage  108  is not limited to the configuration shown in  FIG. 4  and may be any configuration as long as the history data includes the customer phone number  214  and counterpart phone number  216 . The notification adequacy determination rules  208  are configured on the basis of data included in the history data stored in the history data storage  108 . 
         [0039]      FIG. 5  is a block diagram illustrating an outline configuration of a first communication server executing an identifier change notification method according to a first embodiment of the present invention.  FIG. 6  is a flowchart illustrating a processing flow of a first communication server executing an identifier change notification method according to a first embodiment of the present invention. 
         [0040]    When an acquaintance of the phone number changer  100  makes a call to the previous phone number  204  of the phone number changer  100  from a third phone  112 , the call is received by the first communication server  102  via a second communication server  114 . 
         [0041]    A call receiver  122  acquires the caller number  232  and destination number  234  (operation S 102 ) and outputs the acquired numbers to a history data acquirer  124 . 
         [0042]    The history data acquirer  124  search the history data storage  108  for history data  236  including the destination number  234  as the customer phone number  214  and the caller number  232  as the counterpart phone number  216  (operation S 106 ) and then outputs the acquired history data  236  as well as the caller number  232  and destination number  234  to a notification adequacy determiner  126 . If there is no history data including the destination number  234  as the customer phone number  214  (No in operation S 104 ), a normal inbound connection process is performed (operation S 120 ). This process will not be described. 
         [0043]    The notification adequacy determiner  126  searches the number notification data storage  110  for number notification data including the destination number  234  as the previous phone number  204  to acquire the notification adequacy determination rules  208  and the new phone number  206  (operation S 108 ). The notification adequacy determiner  126  analyses the history data  236  in accordance with the notification adequacy determination rules  208  so as to determine adequacy of notification of the phone number change (operation S 110 ). Then the notification adequacy determiner  126  outputs a determination result  238  as well as the caller number  232  and new phone number  206  to a report data transmitter  130 . If the determination result  238  indicates that notification is adequate (Yes in operation S 112 ), the notification adequacy determiner  126  outputs the new phone number  206  to a notification data transmitter  128 . If the determination result  238  indicates that notification is inadequate (No in operation S 112 ), a normal connection refusal process (operation S 118 ) is performed. The normal connection refusal process is the same process usually performed when the destination number  234  is invalid, thus the process will not be described. 
         [0044]    The notification data transmitter  128  incorporates the new phone number  206  into a previously prepared audio notification message and then transmits the resultant message  242  as a response to the above-described call (operation S 114 ). Instead of transmitting the audio notification message, the first communication server  102  may connect the above-described call to the second phone  106  which is identified with the new phone number  206 . 
         [0045]    The report data transmitter  130  selects an audio report message in accordance with the determination result  238  from among audio report messages previously prepared for each determination result, incorporates the caller number  232  into the selected audio report message, and transmits the resultant message  240  to the second phone  106  which is identified with the new phone number  206 . Or the report data transmitter  130  may register the resultant message  240  as an audio mail addressed to the new phone number  206 . The processing result of the notification data transmission may be notified to the report data transmitter  130  by the notification data transmitter  128 , and an audio report message or mail reflecting the processing result may be transmitted or registered. 
         [0046]    An incoming call to the new phone number  206  may be refused to connect if the caller number  232  is determined, by the notification adequacy determiner  126 , to be inadequate to be notified of the phone number change.  FIG. 7  is a flowchart illustrating a processing flow of a first communication server according to a first embodiment of the present invention when receiving an incoming call to a new phone number. If the history data storage  108  stores no history data including the destination number  234  as the customer phone number  214  (No in operation S 104 ), the history data acquirer  124  searches the number notification data storage  110  for number notification data including the destination number  234  as the new phone number  206  to acquire the previous phone number  204  (operation S 124 ). The history data acquirer  124  searches the history data storage  108  for the history data  236  including the previous phone number  204  as the customer phone number  214  and the caller number  232  as the counterpart phone number  216  (operation S 126 ) and then outputs the acquired history data  236  as well as the caller number  232  and destination number  234  to the notification adequacy determiner  126 . 
         [0047]    The notification adequacy determiner  126  searches the number notification data storage  110  for number notification data including the destination number  234  as the new phone number  206  to acquire the notification adequacy determination rules  208  (operation S 128 ). The notification adequacy determiner  126  analyses the history data  236  in accordance with the notification adequacy determination rules  208  to determine adequacy of the connection. If the notification adequacy determiner  126  determines that notification is adequate, in accordance with the notification adequacy determination rules  208 , the connection may be adequate. If it is determined that notification is inadequate, the connection may be inadequate. If the connection is adequate (Yes in operation S 130 ), a normal inbound connection process is performed (operation S 120 ). If the connection is inadequate (No in operation S 130 ), a normal connection refusal process is performed (operation S 118 ) and the notification adequacy determiner  126  outputs the determination result  238  as well as the caller number  232  and destination number  234  to the report data transmitter  130 . The report data transmitter  130  incorporates the caller number  232  into a previously prepared audio report message and then transmits the resultant message  240  to the second phone  106  which is identified with the destination number  234  (operation S 116 ). Or the report data transmitter  130  may register the resultant message  240  as an audio mail addressed to the destination number  234 . 
         [0048]    An incoming call to the new phone number  206  may be refused to connect if a call has been made from the caller number  232  to the previous phone number  204  and no phone number change notification has been provided thereto.  FIG. 8  is a flowchart illustrating a processing flow of a first communication server according to a first embodiment of the present invention when receiving an incoming call to a new phone number. If it is determined that notification is inadequate for an incoming call to the previous phone number  204  (No in operation S 112 ), the history data acquirer  124  adds data indicating that notification is inadequate, to the history data  236  including the destination number  234  as the customer phone number  214  and the caller number  232  as the counterpart phone number  216  (operation S 134 ). If the incoming call is not destined for the previous phone number  204 , that is, if the history data storage  108  stores no history data including the destination number  234  as the customer phone number  214  (No in operation S 104 ), the history data acquirer  124  searches the number notification data storage  110  for number notification data including the destination number  234  as the new phone number  206  to acquire the previous phone number  204  (operation S 124 ). The history data acquirer  124  searches the history data storage  108  for the history data  236  including the previous phone number  204  as the customer phone number  214  and the caller number  232  as the counterpart phone number  216  (operation S 126 ). If the acquired history data  236  contains data indicating that notification is inadequate (Yes in operation S 132 ), a normal connection refusal process is performed (S 118 ), and the history data acquirer  124  outputs the caller number  232  and destination number  234  to the report data transmitter  130 . The report data transmitter  130  incorporates the caller number  232  into a previously prepared audio report message and then transmits the resultant message  240  to the second phone  106  which is identified with the destination number  234  (operation S 116 ). Or the report data transmitter  130  may register the resultant message  240  as an audio message addressed to the destination number  234 . 
         [0049]    Although the phone number change notification is provided by the first communication server  102  in the above description, it may be provided by the second phone  106  instead. Such an arrangement is, for example, storing history data related to the previous phone number in a storage of the second phone  106  instead of the history data storage  108 , transferring an incoming call destined for the previous phone number to the second phone  106  from the first communication server  102 , and notifying the second phone  106  that the incoming call is destined for the previous phone number. In this arrangement, transmission of the report message  240  (operation S 116 ) may not be required. 
       Second Embodiment 
       [0050]    Referring now to  FIGS. 9 to 16 , an identifier change notification method according to a second embodiment of the present invention will be described. The second embodiment of the present invention allows notification of the change of a phone mail address.  FIG. 9  is a diagram illustrating relations between phones and communication servers in a description of an identifier change notification method according to a second embodiment of the present invention. 
         [0051]    A phone mail address changer (the person who changes his or her phone mail address)  300  loses a first phone  304  controlled by a first communication server  302  and then uses a second phone  306  controlled by the same server. Accordingly, the phone mail address changer  300  is required to provide notification of a new phone mail address for identifying the second phone  306 , to acquaintances who know only the previous phone mail address for identifying the first phone  304 . The first communication server  302  stores history data relating to phones under its control in history data storage  308 . The phone mail address changer  300  sets rules for determining whether to provide notification of the new phone mail address on the basis of the history data stored in the history data storage  308 . These rules are contained in address notification data stored in address notification data storage  310  of the first communication server  302 . The phones and communication servers shown in  FIG. 9  may communicate with one another over communication networks  316 ,  318 , and  320 . 
         [0052]      FIG. 10  is a diagram illustrating an example configuration of address notification data according to a second embodiment of the present invention. A customer ID  402  is data for uniquely identifying the phone mail address changer  300 . A previous phone mail address  404  is a phone mail address of the phone mail address changer  300  before a phone mail address change is made, and serves as a destination address when receiving incoming phone mails from acquaintances of the phone mail address changer  300 . A new phone mail address  406  is a phone mail address of the phone mail address changer  300  after the phone mail address change is made and serves as a main part of address notification data when a phone mail address change notification is provided. Notification adequacy determination rules  408  will be described later. A notification start date  410  is the start date of a phone mail address change notification service. A notification end date  412  is the end date of the phone mail address change notification service. The configuration of the address notification data stored in the address notification data storage  31 Q is not limited to the configuration shown in  FIG. 10  and may be any configuration as long as the address notification data stored in the address notification data storage  310  includes the previous phone mail address  404 , new phone mail address  406 , and notification adequacy determination rules  408 . 
         [0053]      FIG. 11  is a diagram illustrating examples of notification adequacy determination rules according to a second embodiment of the present invention. Each rule record contains a rule ID  452  identifiable of the rule, a notification adequacy  454  indicating a determination result, and conditions for determination. In this example, adequacy of notification is determined on the basis of an incoming phone mail count  458 , an outgoing phone mail count  460 , or an average received data amount  462  during a target period  456  contained in the history data stored in the history data storage  308 . Any blank item in  FIG. 11  indicates that no condition is set for the blank item. A rule_ 21  indicates that the new phone mail address  406  will not be provided to a target to which no phone mail has been sent during the last 30 days according to the history data stored in the history data storage  308 . A rule_ 22  indicates that the new phone mail address  406  will not be provided to a target from which no phone mail has been received during the last 10 days according to the history data stored in the history data storage  308 . A rule_ 23  indicates that the new phone mail address  406  will not be provided to a target from which more than ten phone mails have been received and an average data amount of the received incoming phone mails exceeds 1000 kB through the entire period of time according to the history data stored in the history data storage  308 . The phone mail address changer  300  defines rules in such manners. Accordingly, notification of the new phone mail address  406  is provided to targets that do not satisfy the conditions set under these rules. The rules shown in  FIG. 11  are applicable as long as the history data stored in the history data storage  308  includes, for example, data on the date and time of receiving phone mails, the date and time of sending phone mails, and the amount of received data. The notification adequacy determination rules  408  are not limited to what are shown in  FIG. 11  and any arbitrary rule may be set on the basis of data on the count or frequency of incoming/outgoing phone mails, an amount of sent/received data, an hour of day of incoming/outgoing phone mails, a character string included in an incoming phone mail, an operation for refusing phone mail reception, or the like obtained from the history data stored in the history data storage  308 . In addition to rules based on data on the history data stored in the history data storage  308 , rules based on data on the currently received incoming phone mail may be set. Such rules may include a rule based on the time of phone mail reception, a source address registered to a phone mail reception refusal list, or the like. 
         [0054]      FIG. 12  is a diagram illustrating an example configuration of history data according to a second embodiment of the present invention. A customer phone mail address  414  is a phone mail address controlled by the first communication server  302 . For the sake of convenience, it is assumed that the history data storage  308  stores history data relating to the previous phone mail address of only a customer requesting the phone mail address change notification service. A counterpart phone mail address  416  is a phone mail address of a counterpart which the customer identified with the customer phone mail address  414  has sent or received a phone mail to or from. An incoming date &amp; time  418  is data indicating the date and time of when the phone mail has been received. An outgoing date &amp; time  420  is data indicating the date and time of when the phone mail has been sent. A received data amount  422  is the amount of data contained in a received incoming phone mail. A sent data amount  424  is the amount of data contained in a sent phone mail. The configuration of the history data stored in the history data storage  308  is not limited to the configuration shown in  FIG. 12  and may be any configuration as long as the history data includes the customer phone mail address  414  and counterpart phone mail address  416 . The notification adequacy determination rules  408  are configured on the basis of data included in the history data stored in the history data storage  308 . 
         [0055]      FIG. 13  is a block diagram illustrating an outline configuration of a first communication server executing an identifier change notification method according to a second embodiment of the present invention.  FIG. 14  is a flowchart illustrating a processing flow of a first communication server executing an identifier change notification method according to a second embodiment of the present invention. 
         [0056]    When an acquaintance of the phone mail address changer  300  sends a phone mail to the previous phone mail address  404  of the phone mail address changer  300  from a third phone  312 , the phone mail is received by the first communication server  302  via a second communication server  314 . 
         [0057]    A phone mail receiver  322  acquires a source address  432  and destination address  434  (operation S 302 ) and outputs the acquired addresses to a history data acquirer  324 . 
         [0058]    The history data acquirer  324  searches the history data storage  308  for history data  436  including the destination address  434  as the customer phone mail address  414  and the source address  432  as the counterpart phone mail address  416  (operation S 306 ) and then outputs the acquired history data  436  as well as the source address  432  and destination address  434  to a notification adequacy determiner  326 . If there is no history data including the destination address  434  as the customer phone mail address  414 , a normal phone mail delivery process is performed (operation S 320 ). This process will not be described. 
         [0059]    The notification adequacy determiner  326  searches the address notification data storage  310  for address notification data including the destination address  434  as the previous phone mail address  404  to acquire the notification adequacy determination rules  408  and the new phone mail address  406  (operation S 308 ). The notification adequacy determiner  326  analyses the history data  436  in accordance with the notification adequacy determination rules  408  so as to determine adequacy of notification of the phone mail address change (operation S 310 ). Then the notification adequacy determiner  326  outputs a determination result  438  as well as the source address  432  and new phone mail address  406  to a report data deliverer  330 . If the determination result  438  indicates that notification is adequate (Yes in operation S 312 ), the notification adequacy determiner  326  outputs the source address  432 , destination address  434 , and new phone mail address  406  to a notification data transmitter  328 . If the determination result  438  indicates that notification is inadequate (No in operation S 312 ), a normal delivery refusal process (operation S 318 ) is performed. The normal delivery refusal process is the same process usually performed when the destination address  434  is invalid, thus the process will not be described. 
         [0060]    The notification data transmitter  328  incorporates the destination address  434  and new phone mail address  406  into a previously prepared notification message and then transmits the resultant message  442  as a replying phone mail to the source address  423  (operation S 314 ). A new phone number as well as the new phone mail address  406  may be incorporated into the notification message. Thus, the phone mail source may be also notified that a phone number has been changed. Also, the incoming phone mail may be delivered to a mailbox  332  for the new phone mail address  406  while transmitting the notification message as a phone mail. 
         [0061]    The report data deliverer  330  selects a report message in accordance with the determination result  438  from among report messages previously prepared for each determination result, incorporates the source address  432  into the selected report message, and delivers the resultant message  440  to the mailbox  332  for the new phone mail address  406 . The processing result of the notification data transmission may be notified to the report data deliverer  330  by the notification data transmitter  328 , and a report message reflecting the processing result may be delivered. 
         [0062]    A phone mail to the new phone mail address  406  may be refused to deliver if the source address  432  is determined, by the notification adequacy determiner  326 , f to be inadequate to be notified of the phone mail address change.  FIG. 15  is a flowchart illustrating a processing flow of a first communication server according to a second embodiment of the present invention when receiving an incoming phone mail to a new phone mail address. If the history data storage  308  stores no history data including the destination address  434  as the customer phone mail address  414  (No in operation S 304 ), the history data acquirer  324  searches the address notification data storage  310  for address notification data including the destination address  434  as the new phone mail address  406  to acquire the previous phone mail address  404  (operation S 324 ). The history data acquirer  324  searches the history data storage  308  for the history data  436  including the previous phone mail address  404  as the customer phone mail address  414  and the source address  432  as the counterpart phone mail address  416  (operation S 326 ) and then outputs the acquired history data  436  as well as the source address  432  and destination address  434  to the notification adequacy determiner  326 . 
         [0063]    The notification adequacy determiner  326  searches the address notification data storage  310  for address notification data including the destination address  434  as the new phone mail address  406  to acquire the notification adequacy determination rules  408  (operation S 328 ). The notification adequacy determiner  326  analyses the history data  436  in accordance with the notification adequacy determination rules  408  to determine adequacy of the delivery. If it is determined that notification is adequate, in accordance with the notification adequacy determination rules  408 , the delivery may be adequate. If it is determined that notification is inadequate, the delivery is inadequate. If the delivery is adequate (Yes in operation S 330 ), a normal delivery process is performed (operation S 320 ). If the delivery is inadequate (No in operation S 330 ), a normal delivery refusal process is performed (operation S 318 ) and the notification adequacy determiner  326  outputs the determination result  438  as well as the source address  432  and destination address  434  to the report data deliverer  330 . The report data deliverer  330  incorporates the source address  432  into a previously prepared report message and then delivers the resultant message  440  to the mailbox  332  for the destination address  434  (operation S 316 ). Or the report data deliverer  330  may deliver the incoming phone mail regardless of whether the delivery is adequate or not and then, if the delivery is inadequate, the report data deliverer  330  may send a phone mail on normal delivery refusal to the source address  432  and deliver a transmittal report of the phone mail on delivery refusal to the mailbox  332  for the destination address  434 . 
         [0064]    An incoming phone mail to the new phone mail address  406  may be refused to deliver if a phone mail has been sent from the source address  432  to the previous phone mail address  404  and no phone mail address change notification has been provided thereto.  FIG. 16  is a flowchart illustrating a processing flow of a first communication server according to a second embodiment of the present invention when receiving an incoming phone mail to a new phone mail address. If it is determined that notification is inadequate for an incoming phone mail to the previous phone mail address  404  (No in operation S 312 ), the history data acquirer  324  adds data indicating that notification is inadequate, to the history data  436  including the destination address  434  as the customer phone mail address  414  and the source address  432  as the counterpart phone mail address  416  (operation S 334 ). If the incoming phone mail is not destined for the previous phone mail address  404 , that is, if the history data storage  308  stores no history data including the destination address  434  as the customer phone mail address  414  (No in operation S 304 ), the history data acquirer  324  searches the address notification data storage  310  for address notification data including the destination address  434  as the new phone mail address  406  to acquire the previous phone mail address  404  (operation S 324 ). The history data acquirer  324  searches the history data storage  308  for the history data  436  including the previous phone mail address  404  as the customer phone mail address  414  and the source address  432  as the counterpart phone mail address  416  (operation S 326 ). If the acquired history data  436  contains data indicating that notification is inadequate (Yes in operation S 332 ), a normal delivery refusal process is performed (operation S 318 ), and the history data acquirer  324  outputs the source address  432  and destination address  434  to the report data deliverer  330 . The report data deliverer  330  incorporates the source address  432  into a previously prepared report message and then delivers the resultant message  440  to the mailbox  332  for the destination address  434 . Alternatively, the report data deliverer  330  may deliver the incoming phone mail, send a phone mail on normal delivery refusal to the source address  432 , and deliver a transmittal report of the phone mail on delivery refusal to the mailbox  332  for the destination address  434 . 
         [0065]    Although the phone mail address change notification is provided by the first communication server  302  in the above description, it may be provided by the second phone  306  instead. Such an arrangement is, for example, storing history data related to the previous phone mail address in a storage of the second phone  306  instead of the history data storage  308 , delivering an incoming phone mail destined for the previous phone mail address to the mailbox  332  for the new phone mail address with a memo reporting that the incoming phone mail is destined to the previous phone mail address. In this case, delivery of report message  440  (operation S 316 ) may not be required. 
         [0066]    The identifier change notification apparatus according to the above-described embodiments may be performed not only using hardware but also using software of a computer. For example, in the first embodiment, by creating a program for causing a computer to perform the functions of the call receiver  122 , history data acquirer  124 , notification adequacy determiner  126 , notification data transmitter  128 , and report data transmitter  130  shown in  FIG. 5  and by causing a memory of a computer to read and execute the program, the first communication server  102  shown in  FIG. 5  is achieved. The second embodiment may also be achieved using software (program) of a computer. 
         [0067]    Programs for achieving the identifier change notification methods according to the embodiments of the present invention may be stored in any of a transportable recording medium  502  such as a CD-ROM, a CD-RW, a DVD-R, a DVD-RAM, a DVD-RW, and a flexible disk, another storage unit  506  provided on a communication line  504 , and a storage unit or recording medium  508  of a computer system  500 , such as a hard disk or a RAM. The program is loaded into a main memory and executed therein.