Abstract:
Internet Protocol (IP) telephone number information system performs for the telephone number in the existing communication systems. A number information server in the system has a region information database representing an IP telephony service area for each of a plurality of Internet Service Providers (ISPs) having a corporate information database. The number information server specifies one of the plurality of ISPs from the region information database, based on a search condition input from a user terminal connected to the Internet. The specified ISP searches the corresponding corporate information database, and obtains number information matching the search condition. The number information server notifies the user terminal of the number information obtained from searching the corporate information database, in response to the search condition input from the user terminal.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a method for providing a telephone number information service in Internet Protocol telephone service (IP telephony), and more particularly a method for providing a telephone number information service in IP telephony enabling corporate information search for each region on which the corporation is based, such as telephone number of a corporation contracting with an Internet Service Provider (ISP: a service provider providing a connection service to the Internet) which provides ‘Voice over Internet Protocol’ (VoIP: a voice communication service using a telephone number with a particular prefix such as ‘050’, using the Internet as communication infrastructure, which is referred to as IP telephony).  
         [0003]     2. Description of the Related Art  
         [0004]     With wide spread of the Internet, use of low cost IP telephony is becoming popular. In particular, to obtain subscribers, Internet Service Providers (ISPs) take into view the provision of IP telephony services.  
         [0005]     In case of portable telephone mainly owned personally, a telephone number information service is not particularly necessary. However, in case of IP telephony, particularly when a corporate body obtains an IP telephone number, it becomes necessary for the corporate body to make the obtained telephone number known to others through the telephone number information service, because the way of use is near to a fixed telephone service.  
         [0006]     In case of a fixed network, implementation of the information service is easy, because the telephone service is mostly provided by a restricted number of authorized telephone service providers. Since such telephone service providers own nationwide information, when searching a telephone number, it becomes necessary for the users to begin the search with specifying the region of the target.  
         [0007]     The methods for installing such a service are shown in  FIGS. 1, 2 . A typical system is disclosed in the official gazette of the Japanese Unexamined Patent Publication No. 2003-125084, as shown in  FIG. 1 . In this system, a number information service user  2  receives telephone number information from an information database  12  through the Internet  3 , using a Web browser  20 . Information database  12  includes corporate telephone numbers, etc. open to public, and is installed in a Web server  1  to provide the telephone number information service. Number information service user  2  sends a request for telephone number information by accessing Web content  10  provided for number information. Web server  1  searches database  12  using a search engine  11 , and displays the search result on Web browser  20 . Thus, the number information service user can receive the desired telephone number.  
         [0008]      FIG. 2  shows an example of utilizing a telephone number information system provided in a telephone office  1   1 . Telephone office  1   1  provides a telephone number information operator  10   1 , and a telephone number database  12   1 . Using a telephone set  20   1 , number information service user  2  receives a search result obtained by searching telephone number database  12   1 , from telephone number information operator  10   1  through a telephone line network  3   1 .  
         [0009]     As such, in the conventional systems, by inputting a search condition to Web contents  10  or operator  10   1  (by selecting on the browser or through voice), database  12  is searched for the corresponding information, and the search result is either displayed on Web browser  20  or forwarded via voice announcement.  
         [0010]     As compared with this, in case of IP telephony, assignment of telephone number is not based on an address (location) of the subscriber. Accordingly, in order to actualize provision of telephone number information in an IP telephony service, it is necessary to specify the location of a corporation or an individual who wants to provide telephone number information, etc.  
         [0011]     For this reason, as shown in  FIG. 3 , an IP telephone subscriber  2  accesses a location registration content  10   2  of an ISP  1   2 , and edits a location information database  12   2 , so as to supply the own telephone number to the users of the telephone number information service. Thus, the location of IP telephone subscriber  2  can be specified.  
         [0012]     When an IP telephone set is moved to a different place, IP telephone subscriber  2  again accesses location registration content  10   2  of ISP  1   2 , and edits location information database  12   2  for subscriber  2 . Thus, the system can easily provide the telephone number information of IP telephone subscriber  2  to the users who want to receive it.  
         [0013]     However, IP telephony is serviced by a multiple of Internet Service Providers (ISPs)  1   2 , each managing the telephone numbers on an ISP-by-ISP basis. This makes it very difficult to construct a system for the telephone number information service. Moreover, from the viewpoint of ISP  1   2 , making good use of local features is requested.  
       SUMMARY OF THE INVENTION  
       [0014]     Accordingly, in consideration of the aforementioned IP telephony environment, it is an object of the present invention to provide an IP telephone number information system particularly having local features.  
         [0015]     In order to attain the aforementioned object according to the present invention, as a first aspect, an IP telephone number information system includes a number information server connected through the Internet, and corporate information databases provided in a plurality of Internet Service Providers (ISPs). The number information server includes a region information database indicating IP telephony service areas provided by the plurality of ISPs. Each of the plurality of ISPs comprises a corporate information database, and the number information server specifies one of the plurality of ISPs from the region information database, based on a search condition input from a user terminal connected to the Internet. The specified ISP searches the corresponding corporate information database and obtains number information matching the search condition, and the number information server notifies to the user terminal the number information resulting from searching the corporate information database, in regard to the search condition input from the user terminal.  
         [0016]     As a second aspect of the IP telephone number information system in accordance with the present invention to attain the aforementioned object, in the first aspect, the search condition to be input from the user terminal is input by accessing Web content of the number information server through a Web browser, and narrowing a search condition range properly is enabled on the Web browser.  
         [0017]     As a third aspect of the IP telephone number information system to attain the aforementioned object, in the first aspect, the region information database stores information for specifying ISP in reference to an information pair constituted of region information and additional information. Also, the corporate information database stores an IP telephone number in reference to an information pair constituted of location information and additional information.  
         [0018]     As a fourth aspect of the IP telephone number information system to attain the aforementioned object, in the first aspect, the number information server includes a cache memory for temporarily preserving the searched corporate information, and when the identical search condition is input afterward, the number information server searches the cache memory.  
         [0019]     As a fifth aspect of the IP telephone number information system to attain the aforementioned object, in the fourth aspect, a management terminal connected to the number information server is provided. A supervisory time period is set from the management terminal, and the number information server deletes a preservation area in the cache memory at the set period.  
         [0020]     Further scopes and features of the present invention will become more apparent by the following description of the embodiments with the accompanied drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  shows a diagram illustrating a conventional system in which a user of telephone number information receives telephone number information through the Internet using a Web browser.  
         [0022]      FIG. 2  shows a diagram illustrating a conventional system in which a user receives a telephone number information service from a telephone number information operator.  
         [0023]      FIG. 3  shows a diagram illustrating a conventional system enabling providing a telephone number of the own office to a number information service user.  
         [0024]      FIG. 4  shows a configuration diagram of an IP telephone number information system, according to an embodiment of the present invention.  
         [0025]      FIG. 5  shows an explanation diagram illustrating operation for narrowing down a search range by inputting keyword selection on a Web browser from a number information service user shown in  FIG. 4 .  
         [0026]      FIG. 6  shows a diagram illustrating an embodiment in which the user further expands the search range from the obtained search result output on the Web browser of the number information service user in step S 5 , in the embodiment shown in  FIG. 4 .  
         [0027]      FIG. 7  shows a diagram illustrating an embodiment to improve search efficiency by use of a cache.  
         [0028]      FIG. 8  shows a diagram illustrating a management method of a temporary preservation area  13  (cache memory) in a telephone number information server  1  in the embodiment shown in  FIG. 7 .  
         [0029]      FIG. 9  shows an example for preventing temporarily preserved corporate information from becoming out of date, similar to the embodiment shown in  FIG. 8 .  
         [0030]      FIG. 10  shows a diagram illustrating still another management method of a temporary preservation area of a cache memory, initiated from a management terminal.  
         [0031]      FIG. 11  shows a diagram illustrating an example of a different management method of the cache memory for preventing preserved corporate information from becoming out of date.  
         [0032]      FIG. 12  shows a diagram illustrating a second example of the different management method of cache memory for preventing preserved corporate information from becoming out of date.  
         [0033]      FIG. 13  shows a diagram illustrating a third example of the different management method of cache memory for preventing preserved corporate information from becoming out of date.  
         [0034]      FIG. 14  shows an exemplary configuration to improve search efficiency when searching region information and corporate information.  
         [0035]      FIG. 15  shows an exemplary configuration to improve efficiency by grouping Internet Service Providers (ISPs) having corporate information.  
         [0036]      FIG. 16  shows a diagram illustrating creation of region information.  
         [0037]      FIG. 17  shows a diagram illustrating a process when corporate information is added.  
         [0038]      FIG. 18  shows a diagram illustrating an example of automatically creating region information and storing the created information into a region information database.  
         [0039]      FIG. 19  shows a diagram illustrating deletion and update of corporate information databases.  
         [0040]      FIG. 20  shows a diagram illustrating deletion and update of region information by setting a supervisory time period.  
         [0041]      FIG. 21  shows a diagram illustrating deletion and update of region information by a region information management means.  
         [0042]      FIG. 22  shows a diagram illustrating a method of deleting and updating region information by timer setting.  
         [0043]      FIG. 23  shows a diagram illustrating a method of deleting and updating region information by date and time setting.  
         [0044]      FIG. 24  shows a diagram illustrating a method of deleting and updating region information corresponding to the case of no matched record found (NL) based on a search result.  
         [0045]      FIG. 25  shows a diagram illustrating a method of deleting and updating region information by setting an access count.  
         [0046]      FIG. 26  shows a diagram illustrating a method of deleting and updating region information by setting a supervisory time period. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0047]     The preferred embodiment of the present invention is described hereinafter referring to the charts and drawings. However, it is noted that the scope of the present invention is not limited to the embodiments described below.  
         [0048]      FIG. 4  shows a configuration diagram of an IP telephone number information system, according to an embodiment of the present invention. In  FIG. 4 , number information service user  2  accesses to Web content  10  provided in telephone number information server  1  using HTTP (Hypertext Transfer Protocol) (step S 1 ), and input a search condition (step S 1 ).  
         [0049]     From Web content  10 , the search condition input by number information service user  2  is fed to a search engine  11  (step S 2 ).  
         [0050]     Telephone number information server  1  has a region information database  120 . This region information database  120  represents the relation of correspondence between the region of each ISP and additional information. Therefore, search engine  11  accesses region information database  120 , and collects a record(s) in region information database  120  of which ‘region’ field matches the search condition, by which the Internet Service Provider(s) ISP 1 , ISP 2  to be searched is specified.  
         [0051]     Search engine  11  collects a record(s) of which ‘location’ field in corporate information database  121 ,  122  of the specified Internet Service Provider(s) ISP 1 , ISP 2  to be searched matches a ‘region’ field in region information database  120 , using SQL (Structure Query Language) (steps S 4 - 1 , S 4 - 2 ).  
         [0052]     Next, the collected corporate information is output to a Web browser  20  in number information service user  2  in the HTML (Hypertext Markup Language) format.  
         [0053]     Here, as mentioned above, corporate information databases  121 ,  122  of the Internet Service Providers ISP 1 , ISP 2  are searched for ‘location’ data, using ‘region’ information in region information database  120  as an index. However, as a modification, it may also be possible to perform the data search using the following method.  
         [0054]     Namely, the following information is available as a search index key: address, station name, line name of electric train, postal code, telephone number, landmark (building, facilities), latitude and longitude, “Mapcode” (i.e. a location code in Japan developed by Denso Corp.), “Standard grid square code” (based on “Standard Grid Squares and Standard Grid Square Code used for the Statistics”, Announcement No. 143 by the then Administrative Management Agency of Japan on Jul. 12, 1973), road name, intersection name, interchange, bus stop, bus route, province, river, mountain, see, etc. The search may be performed using the above information individually, or in combination thereof.  
         [0055]     Further, as shown in  FIG. 5 , number information service user  2  can request to narrow down a search range by inputting selected keyword on Web browser  20 . Or, number information service user  2  can request to expand the search range through the operation for expanding the region for search, as shown in  FIG. 6 .  
         [0056]     In  FIG. 5 , number information service user  2  accesses Web content  10  provided in telephone number information server  1  using HTTP, and inputs a search condition (step S 1 ). Further, number information service user  2  selects (clicks) a ‘keyword’ KW. (In  FIG. 5 , hospital/clinic is selected.) (step S 1   1 ).  
         [0057]     From Web content  10 , the search condition and the keyword input by number information service user  2  are fed to search engine  11  (step S 2 ).  
         [0058]     Search engine  11  collects a record(s) of which ‘region’ field in region information database  120  matches the search condition, and at the same time ‘additional information’ field in the region information matches the keyword, and specifies the Internet Service Provider(s) ISP 1 , ISP to be searched (step S 3 ).  
         [0059]     Search engine  11  collects a record(s) of which ‘location’ field incorporate information database(s)  121 ,  122  of the Internet Service Provider(s) ISP 1 , ISP 2  matches the ‘region’ field in region information database  120 , and at the same time, ‘additional information’ field in corporate information databases  121 ,  122  matches the ‘additional information’ field in region information database  120  (step S 4 ).  
         [0060]     Search engine  11  then outputs the collected corporate information to Web browser  20  in number information service user  2 , in the HTML format.  
         [0061]     Here, as a modification of the ‘additional information’ for narrowing the search range, it is also possible to use business category, ISP, etc.  
         [0062]     Also, in consideration of a case such that the search condition does not match data in region information database  120 , by creating and deleting region information database  120  automatically, region information database  120  can be maintained up to date as will be described later.  
         [0063]      FIG. 6  shows a diagram illustrating an embodiment in which the user further expands a search range from the obtained search result output on Web browser  20  of number information service user  2  in step S 5 , in the embodiment shown in  FIG. 4 .  
         [0064]     Number information service user  2  expands, and inputs, the search condition using Web browser  20  (from  20 A to  20 B) (step S 1 ). For example, number information service user  2  expands a search condition of the location address from “1-3 Minato-ku, Tokyo” to “Tokyo Metropolis”. Corresponding to this, the search condition is fed from Web content  10  to search engine  11  (step S 2 ).  
         [0065]     Next, search engine  11  collects a record(s) of which ‘region’ field in region information database  120  matches the search condition (step S 3 ), and specifies the Internet Service Provider(s) ISP 1 , ISP 2  to be searched. Then, using SQL, search engine  11  collects a record(s) of which ‘location’ field incorporate information database(s)  121 ,  122  of the Internet Service Provider(s) ISP 1 , ISP 2  to be searched matches the ‘region’ field in region information database  120  (step S 4 ). Search engine  11  then outputs the collected corporate information to Web browser  20  in number information service user  2 , in the HTML format.  
         [0066]      FIG. 7  shows a diagram illustrating an embodiment to improve search efficiency by use of a cache memory (or simply, a cache), as a feature of the present invention. In  FIG. 7 , number information service user  2  expands, and inputs, the search condition using Web browser  20  (step S 1 ). For example, number information service user  2  expands a search condition of the location address from “1-3 Minato-ku, Tokyo” to “Tokyo Metropolis”. Corresponding to this, the search condition is fed from Web content  10  to search engine  11  (step S 2 ).  
         [0067]     Next, search engine  11  collects a record(s) of which ‘region’ field in region information database  120  matches the search condition (step S 3 ), and specifies the Internet Service Provider(s) ISP 1 , ISP 2  to be searched. Then, using SQL, search engine  11  collects a record(s) of which ‘location’ field incorporate information database(s)  121 ,  122  of the Internet Service Provider(s) ISP 1 , ISP 2  to be searched matches the ‘region’ field in region information database  120  (steps S 4 - 1 , S 4 - 2 ). Search engine  11  then outputs the collected corporate information to Web browser  20  in number information service user  2 , in the HTML format (step S 5 ).  
         [0068]     Here, according to the embodiment shown in  FIG. 7 , ‘corporate information’ is also stored into a temporary preservation storage area  13 . With this, it becomes possible to improve search efficiency when successive searches are performed in reference to the same search condition.  
         [0069]      FIG. 8  shows a diagram illustrating a management method of temporary preservation area (cache memory)  13  in a telephone number information server  1 , in the embodiment shown in  FIG. 7 . As shown in  FIG. 8 , a management terminal  30  is provided. From this management terminal  30 , a supervisory time period for supervising the temporary preservation area is set into a cache manager  14  (step S 10 ) At each supervisory time period being input and set from management terminal  30 , cache manager  14  deletes the corporate information, which has temporarily been stored in cache memory  13 , at the time period input from management terminal  30 . With this function, it becomes possible to prevent the corporate information temporarily stored in cache memory  13  from becoming out of date.  
         [0070]     Similar to the embodiment shown in  FIG. 8 ,  FIG. 9  shows an example for preventing the temporarily preserved corporate information from becoming out of date. When the corporate information in corporate information database  121  managed by the Internet Service Provider ISP 1  is deleted (DL), the deleted corporate information is transmitted to cache manager  14  in telephone number information server  1  (step S 4 - 3 ). Cache manager  14  in telephone number information server  1  searches the temporary preservation area in cache memory  13 , and if there is any data matching the received corporate information in the temporary preservation area, cache manager  14  deletes this data. With this function, it is possible to prevent the temporarily stored corporate information from becoming out of date.  
         [0071]      FIG. 10  shows a diagram illustrating another management method of the temporary preservation area in cache memory  13 , initiated from management terminal  30 . When search engine  11  in telephone number information server 1 caches the corporate information into cache memory  13 , search engine  11  sets a timer for the corporate information concerned (step S 5 - 1 ).  
         [0072]     The timer value set by search engine  11  and a supervisory time period for supervising the timeout of the timer to be measured are set in advance from management terminal  30  (step S 10 - 1 ).  
         [0073]     Cache manager  14  checks the timer value of the corporate information preserved in cache memory  13  at the period set in the step S 10 - 1 . If a timeout occurs, cache manager  14  deletes the corresponding corporate information (step S 11 - 1 ). With this function, the temporarily preserved corporate information is prevented from becoming out of date.  
         [0074]     FIGS.  11  to  13  show diagrams respectively illustrating examples of other management methods for the cache memory to prevent the preserved corporate information from becoming out of date.  
         [0075]     Referring to  FIG. 11 , when search engine  11  caches ‘corporate information’ into cache memory  13 , search engine  11  sets the date and time of the corporate information being generated in the cache (step S 51 ). Also, at the time of searching, search engine  11  checks cache memory  13 , and updates the date and time if matched corporate information exists.  
         [0076]     Here, both the lapse of time from the latest access date and time to delete the corporate information preserved in cache memory  13  and the time period for supervising the date and time are set in advance from management terminal  30  to cache manager  14  (step S 10 ). Cache manager  14  checks the date and time of the corporate information preserved in cache memory  13  at the period having been set in the step S 10 - 2 , and if the lapse of time from the latest access date and time exceeds the preset value, cache manager  14  deletes the corresponding corporate information (step S 11 ). With this function, the temporarily preserved corporate information is prevented from becoming out of date.  
         [0077]     In  FIG. 12 , when search engine  11  caches the corporate information into cache memory  13 , search engine  11  sets an access count for the corporate information concerned (step S 11 : In this embodiment, the access count is assumed to set to  10 .)  
         [0078]     Further, search engine  11  checks cache memory  13  at the time of searching. When matched corporate information is found, search engine  11  increments the access count. The time period for supervising the access count is set in advance from management terminal  30  (step S 10 ). Cache manager  14  decrements the access count for the corporate information preserved in cache memory  13  at the period preset in the step S 10 .  
         [0079]     If the access count becomes zero, cache manager  14  deletes the corresponding corporate information (step S 11 ) With this function, the temporarily preserved corporate information is prevented from becoming out of date.  
         [0080]     In the example shown in  FIG. 13 , the time period to be supervised and a condition for deletion are input from management terminal  30  (step S 10 ). Cache manager  14  compares the corporate information preserved in cache memory  13  with the deletion condition (additional information or location information) at the period preset in the step S 10 . When the comparison results in a match, cache manager  14  deletes the corresponding corporate information (step S 11 ). With this function, the temporarily preserved corporate information is prevented from becoming out of date.  
         [0081]     Now,  FIG. 14  shows an exemplary configuration to improve search efficiency of searching ‘region information’ and ‘corporate information’.  
         [0082]     In  FIG. 14 , number information service user  2  accesses Web content  10  provided in telephone number information server  1  using HTTP, and inputs a search condition (step S 1 ).  
         [0083]     The search condition input by number information service user  2  is fed from Web content  10  to search engine  11  (step S 2 ). Search engine  11  searches region information database  120 , and collects a record(s) of which ‘region’ field in region information database  120  matches the search condition, and specifies the Internet Service Provider(s) to be searched (step S 3 ). At this time, search engine  11  increments the ‘count’ field in region information database  120 , and compares the number with the number stored in the previous record. If the value in the ‘count’ field is larger than the value in the previous record, then search engine  11  replaces the record with the newly obtained record (step S 4 ).  
         [0084]     Then, using SQL, search engine  11  collects a record(s) of which ‘location’ field incorporate information database  121  of the Internet Service Provider ISP 1  to be searched matches the ‘region’ field in region information database  120 . At this time, search engine  11  increments the ‘count’ field in corporate information database  121 , and compares the count value with the value stored in the previous record. If the value in the ‘count’ field is larger than the value in the previous record, then search engine  11  replaces the record with the newly obtained record (step S 4 ).  
         [0085]     Search engine  11  then outputs the collected corporate information to Web browser  20  in number information service user  2  in the HTML format. With this function, search efficiency of searching the region information and corporate information can be increased.  
         [0086]      FIG. 15  shows an exemplary configuration to improve efficiency by grouping the Internet Service Providers (ISPs) based on the location in the corporate information.  
         [0087]     In  FIG. 15 , number information service user  2  accesses Web content  10  provided in telephone number information server  1  using HTTP, and inputs a search condition (step S 1 ).  
         [0088]     The search condition input by number information service user  2  is fed from Web content  10  to search engine  11  (step S 2 ).  
         [0089]     Search engine  11  refers to region information database  120 , and collects a record(s) of which ‘region’ field in the region information matches the search condition, and specifies the ISP group to be searched (step S 3 ).  
         [0090]     Using the specified group number, search engine  11  searches a group database  110 , and specifies the Internet Service Provider(s) ISP 1 -ISP 4  to be searched (step S 4 ).  
         [0091]     Then, using SQL, search engine  11  collects a record(s) of which ‘location’ field incorporate information database  121 ,  122  of the Internet Service Provider(s) to be searched matches the ‘region’ field in the region information (step S 4 ). Search engine  11  then outputs the collected corporate information to Web browser  20  in number information service user  2  (step S 5 ).  
         [0092]      FIG. 16  shows a diagram illustrating creation of the region information. In  FIG. 16 , a time period is input from management terminal  30  (step S 20 ), which is set to a region information manager  16 . At the above period, each corporate information database  121 ,  122  of the Internet Service Provider ISP 1 , ISP 2  is searched, and ‘region information’ is created. The created region information is stored into region information database  120 .  
         [0093]      FIG. 17  shows a diagram illustrating a process when ‘corporate information’ is added. When the corporate information is added in each Internet Service Provider ISP 1 , ISP 2 , the added corporate information is transmitted to region information manager  16  provided in telephone number information server  1  (step S 22 ). On receipt of this information, region information manager  16  creates region information database  120  based on the received corporate information.  
         [0094]      FIG. 18  shows a diagram illustrating an example of automatically creating ‘region information’ and storing the created information into region information database  120 . In  FIG. 18 , number information service user  2  accesses Web content  10  provided in telephone number information server  1  using HTTP, and inputs a search condition (step S 1 ). From Web content  10 , the search condition is fed to search engine  11  (step S 2 ).  
         [0095]     Search engine  11  compares the ‘region’ field in region information database  120  with the search condition. As a result of this comparison, if no matched record is found, then search engine  11  compares the search condition with the ‘location’ field in corporate information database  121 ,  122  of each Internet Service Provider ISP 1 , ISP 2 , and checks whether any matched record exists. If there is a matched record(s), search engine  11  automatically creates the region information, and stores the created information into region information database  120 .  
         [0096]      FIG. 19  shows a diagram illustrating update of corporate information databases  121 ,  122 . In  FIG. 19 , a VoIP user 2  accesses Web content  10  provided in telephone number information server  1  using HTTP (step S 1 ), and then the input corporate information is fed from Web content  10  to region information manager  17  (step S 15 ).  
         [0097]     Region information manager  17  automatically creates the region information based on the corporate information. From Web content  10 , the input corporate information is fed to a corporate information manager  18  (step S 17 ). Corporate information manager  18  transmits the corporate information to the corresponding Internet Service Provider ISP 1 , ISP 2 . Each Internet Service Provider ISP 1 , ISP 2  updates each corporate information database  121 ,  122 .  
         [0098]      FIG. 20  shows a diagram illustrating update of region information database  120 . In  FIG. 20 , a supervisory time period of region information database  120  is set from management terminal  30  to region information manager  17  (step S 19 ). Region information manager  17  deletes the entire region information in region information database  120  at the period input from management terminal  30  (step S 16 ). With this function, the region information is prevented from becoming out of date.  
         [0099]     In  FIG. 21 , when the contents registered in corporate information database  121 ,  122  managed by the Internet Service Provider ISP 1 , ISP 2  are deleted, the deleted corporate information is transmitted to region information manager  17  in telephone number information server  1 . (step S 20 ).  
         [0100]     Region information manager  17  then deletes the region information matching the ‘region’ field of the received corporate information (step S 21 ). With this function, the region information is prevented from becoming out of date.  
         [0101]     In  FIG. 22 , when search engine  11  creates the region information into region information database  120 , search engine  11  sets a timer for the region information concerned. Both the timer value set by search engine  11  and the supervisory time period for supervising the occurrence of a timeout in the timer are set in advance from management terminal  30  (step S 10 ).  
         [0102]     Region information manager  17  checks the timer value of the region information at the preset period. On the occurrence of a timeout, region information manager  17  deletes the corresponding region information from region information database  120  (step S 21 ). With this function, the region information is prevented from becoming out of date.  
         [0103]     In  FIG. 23 , when search engine  11  creates the region information, the created date and time are set into the region information. Also, when the region information already exists, search engine  11  updates the date and time in the corporate information.  
         [0104]     The lapse of time from the latest access date and time to the deletion of the region information, as well as the time period for supervising the date and time, is set in advance from management terminal  30 . Region information manager  17  checks the date and time value in the region information at the preset period. When the lapse of time from the date and time of the latest access exceeds the preset value, region information manager  17  deletes the corresponding region information. With this function, the region information is prevented from becoming out of date.  
         [0105]     In  FIG. 24 , number information service user  2  accesses Web content  10  in the telephone number information server by use of HTTP, and inputs a search condition (step S 1 ).  
         [0106]     From Web content  10 , the search condition is fed to search engine  11  (step S 2 ). Search engine  11  collects a record(s) of which ‘region’ field in region information database  120  matches the search condition (step S 3 ), and specifies the Internet Service Provider(s) ISP 1 , ISP 2  to be searched. Next, using SQL, search engine  11  compares the ‘location’ field in corporate information database(s)  121 ,  122  of the Internet Service Provider(s) ISP 1 , ISP 2  to be searched matches the ‘region’ field in region information database  120  (step S 4 ). Based on the comparison result, search engine  11  deletes the region information in region information database  120  corresponding to the case of no matched record found (‘NL’). With this function, the region information is prevented from becoming out of date.  
         [0107]     In  FIG. 25 , when search engine  11  creates the region information, search engine  11  sets the access count for the corporate information concerned. (In this embodiment, the access count is assumed to set to 10.) Further, search engine  11  increments the access count when the region information exists at the time of searching.  
         [0108]     The time period for supervising the access count is set in advance from management terminal  30  (step S 10 ). Region information manager  17  decrements the access count for the region information in region information database  120  at the period preset above. If the access count becomes zero, region information manager  17  deletes the corresponding region information. With this function, the region information is prevented from becoming out of date.  
         [0109]     In  FIG. 26 , the time period to be supervised and a condition for deletion are input from management terminal  30  (step S 10 ). Region information manager  17  compares the region information in region information database  120  with the deletion condition at the preset period. When the comparison results in a match, region information manager  17  deletes the corresponding region information. With this function, the region information is prevented from becoming out of date.  
         [0110]     To summarize, according to the present invention, it becomes possible to provide an IP telephone number information service, like the telephone number information service provided for the existing communication system. With this, the users can receive excellent convenience in IP telephony, which will become more and more popularly used hereafter.  
         [0111]     The foregoing description of the embodiments is not intended to limit the invention to the particular details of the examples illustrated. Any suitable modification and equivalents may be resorted to the scope of the invention. All features and advantages of the invention which fall within the scope of the invention are covered by the appended claims.