Abstract:
It is made possible to share presence information, make address books uniform, and conduct communication between a terminal connected to a system and a terminal connected to another system. An exchange system comprises: an exchange server which is adopted to connect exchange-connected terminals to each other; pseudo exchange-connected terminals which are adopted to be associated respectively with external terminals and which are adopted to function as exchange-connected terminals with respect to the exchange server; pseudo external terminals which are adopted to be associated respectively with the exchange-connected terminals and which are adopted to function as external terminals with respect to an external server; a database which is adopted to retain association relations between first user identification information to be used in the exchange-connected terminals and second user identification information to be used in the external terminals; and a pseudo external terminal &amp; pseudo exchange-connected terminal which is adopted to retrieve the second user identification associated with the first user identification information from the database, retrieve the first user identification associated with the second user identification information from the database, function as the exchange-connected terminal with respect to the exchange server by using the first user identification information, and cause one of the pseudo external terminals to function as an associated external terminal with respect to the external server by using the second user identification information.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an exchange system used to connect an exchange-connected terminal connected to an exchange and an external terminal connected to an external server to each other.  
         [0003]     2. Description of the Related Art  
         [0004]     In recent years, instant message servers (hereafter referred to as “IM servers”) which are communication servers having application sharing functions such as instant messages, presence, audio/video talking and white boards have appeared.  
         [0005]     If a first terminal logs in only one of an IM server intended for ordinary consumers and an exchange intended for enterprises, a second terminal that logs in the other of them cannot give a notice of presence information of the second terminal to the first terminal, according to a conventional technique. Therefore, it is difficult to give a notice of one&#39;s current presence information to all colleagues, customers, acquaintances and friends who keep company with oneself. Even if there is a measure which solves this problem, it is a measure that requires that a special mechanism should be mounted on IM servers intended for ordinary consumers as well. The measure cannot be applied to IM servers intended for ordinary consumers which are basically different in manufacturer and difficult in specification alteration.  
         [0006]     If one has a user account in both the IM server intended for ordinary customer and the exchange intended for enterprise and wants to generate address books in both of them, the address books are not synchronized to each other. At the time of registration and deletion, therefore, it is necessary to conduct the same operation in both terminals twice, resulting in troublesome work. Even if there is a measure which solves this problem, it is a measure that requires that a special mechanism should be mounted on IM servers intended for ordinary consumers as well. The measure cannot be applied to IM servers intended for ordinary consumers which are basically different in manufacturer and difficult in specification alteration.  
         [0007]     Furthermore, if one logs in only one of the IM server intended for ordinary consumers and an exchange intended for enterprises, it is not possible to start a communication session with a terminal user in the other of them. Thus, it is not possible to immediately establish communication with all colleagues, customers, acquaintances and friends who keep company with oneself Even if there is a measure which solves this problem, it is a measure that requires that a special mechanism should be mounted on IM servers intended for ordinary consumers as well. The measure cannot be applied to IM servers intended for ordinary consumers which are basically different in manufacturer and difficult in specification alteration.  
         [0008]     A technique which synchronizes presences between terminals of a user who uses a plurality of terminals is described in JP-A-2004-30371. However, this is synchronization in the case where there are a plurality of terminals connected to the same system. This does not synchronize presences of different systems unlike the present invention.  
         [0009]     A technique of synchronizing a current presence to a presence of a transfer destination is described in JP-A-2003-296525. This technique is different in effect from the present invention which aims at different systems and in particular at IM servers intended for ordinary consumers and synchronizes presences at terminals of different systems used by the same user.  
         [0010]     A technique which processes presence information according to the state of the opposite party when transmitting the presence is described in JP-A-2003-189009. However, there is no concrete technique for the case where the opposite terminal belongs to a different system. Its main object is observability on the terminal side and to prevent transmission of a presence to a terminal having no relation. The technique is different in both object and measure from the present invention.  
         [0011]     A method for mutually connecting presence information between systems which are different in configuration of presence information is described in JP-A-2003-186775. However, the prime object of this method is to absorb the difference in configuration of presence information. A method for connecting completely different servers to each other, such as a system login method and a management method, is not described. The method described in JP-A-2003-186775 differs from the present invention in object, measure and effect.  
         [0012]     As for a technique which connects an existing telephone system and an IM system, a technique which synchronizes presence information according to the line situation of the existing telephone system is described in JP-A-2002-16696. Unlike the present invention, presence information of an existing telephone system terminal instead of the login situation or line is not synchronized. The technique is utterly different from the present invention.  
       SUMMARY OF THE INVENTION  
       [0013]     An object of the present invention is to provide an exchange system which makes it possible to know presence information of a terminal connected to one system, at a terminal connected to the other system.  
         [0014]     Another object of the present invention is to provide an exchange system which makes it possible to automatically conduct synchronization between an address book of one system and an address book of the other system.  
         [0015]     Further object of the present invention is to provide an exchange system which makes it possible to establish a communication session between a terminal connected to one system and a terminal connected to the other system.  
         [0016]     According to the present invention, there is provided an exchange system comprising: an exchange server which is adopted to connect exchange-connected terminals to each other; pseudo exchange-connected terminals which are adopted to be associated respectively with external terminals and which are adopted to function as exchange-connected terminals with respect to the exchange server; pseudo external terminals which are adopted to be associated respectively with the exchange-connected terminals and which are adopted to function as external terminals with respect to an external server; a database which is adopted to retain association relations between first user identification information to be used in the exchange-connected terminals and second user identification information to be used in the external terminals; and a pseudo external terminal &amp; pseudo exchange-connected terminal which is adopted to retrieve the second user identification associated with the first user identification information from the database, retrieve the first user identification associated with the second user identification information from the database, function as the exchange-connected terminal with respect to the exchange server by using the first user identification information, and cause one of the pseudo external terminals to function as an associated external terminal with respect to the external server by using the second user identification information.  
         [0017]     The exchange system may further comprise means for transmitting a presence alternation notice of one of the exchange-connected terminals to the external terminals.  
         [0018]     In the exchange system, the exchange server may be adopted to, upon receiving a presence alteration notice containing the first user identification information from one of the exchange-connected terminals, transfer the presence alteration notice to at least the pseudo external terminal &amp; pseudo exchange-connected terminal; the pseudo external terminal &amp; pseudo exchange-connected terminal may be adopted to, upon receiving the transferred presence alteration notice, retrieve the second user identification information associated with the first user identification information contained in the presence alteration notice, from the database, and transmit a presence alteration notice containing the retrieved second user identification information to the pseudo external terminal; and the pseudo external terminal may be adopted to, upon receiving the presence alteration notice containing the retrieved second user identification information, transfer the presence alteration notice to the external server.  
         [0019]     The exchange system may further comprise means for transmitting a presence alternation notice of one of the external terminals to the exchange-connected terminals.  
         [0020]     In the exchange system, the pseudo external terminal &amp; pseudo exchange-connected terminal may be adopted to, upon receiving a presence alteration notice containing the second user identification information from the external server, retrieve the first user identification information associated with the second user identification information contained in the presence alteration notice, from the database, and transmit a presence alteration notice containing the retrieved first user identification information to the pseudo exchange-connected terminal having the first user identification information; the pseudo exchange-connected terminal may be adopted to, upon receiving the transmitted presence alteration notice, transfer the presence alteration notice to the exchange server; and the exchange server may be adopted to, upon receiving the presence alteration notice containing the first user identification information, transfer the presence alteration notice to the exchange-connected terminals.  
         [0021]     The exchange system may further comprise means for synchronizing a personal address book used by individual one of the exchanged-connected terminals with an external address book used by the external terminals.  
         [0022]     In the exchange system, the database may be adopted to retain association relations between first user identification information used by the exchange-connected terminals and the second user identification information and passwords used by the external terminals, and personal address books associated with the first and second user identification information; the exchange server is adopted to, upon receiving a login notice containing the first user identification information from one of the exchange-connected terminals, transfer the login notice to at least the pseudo external terminal &amp; pseudo exchange-connected terminal; the pseudo external terminal &amp; pseudo exchange-connected terminal, upon receiving the transferred login notice, retrieve the second user identification information and password associated with the first user identification information contained in the login notice, from the database, and transmit a login notice containing the retrieved second user identification information and password to the associated pseudo external terminal; the associated pseudo external terminal may be adopted to, upon receiving the login notice containing the second user identification information and password, log in the external server; the associated pseudo external terminal may be adopted to receive the external address book from the external server; the associated pseudo external terminal may be adopted to acquire the personal address book associated with the first and second user identification information from the database; and the associated pseudo external terminal may be adopted to conduct synchronization between the external address book and the personal address book, and update the external address book and the personal address book in accordance with the synchronization.  
         [0023]     The exchange system may further comprise means for synchronizing a personal address book used by individual one of the exchanged-connected terminals and a shared address book used by all of the exchange-connected terminals with an external address book used by the external terminals.  
         [0024]     In the exchange system, the database may be adopted to retain association relations between first user identification information used by the exchange-connected terminals and the second user identification information and passwords used by the external terminals, the shared address book, and personal address books associated with user identification information; the exchange server may be adopted to, upon receiving a login notice containing the first user identification information from one of the exchange-connected terminals, transfer the login notice to at least the pseudo external terminal &amp; pseudo exchange-connected terminal; the pseudo external terminal &amp; pseudo exchange-connected terminal may be adopted to, upon receiving the transferred login notice, retrieve the second user identification information and password associated with the first user identification information contained in the login notice, from the database, and transmit a login notice containing the retrieved second user identification information and password to the associated pseudo external terminal; the associated pseudo external terminal may be adopted to, upon receiving the login notice containing the second user identification information and password, log in the external server; the associated pseudo external terminal may be adopted to receive the external address book from the external server; the associated pseudo external terminal may be adopted to acquire the shared address book and the personal address book associated with the first and second user identification information from the database; the associated pseudo external terminal may be adopted to conduct synchronization between the external address book and the personal address book, and update the external address book and the personal address book in accordance with the synchronization; and the associated pseudo external terminal may be adopted to conduct synchronization between the external address book and the shared address book, and update the external address book in accordance with the synchronization.  
         [0025]     The exchange system may further comprise means for establishing a communication session between one of the exchange-connected terminals and one of the external terminals.  
         [0026]     In the exchange system, the external terminals may be adopted to be associated respectively with the exchange-connected terminals; the exchange server may be adopted to, upon receiving from first one of the exchange-connected terminals a communication session start request which designates, as an opposite party of communication, a pseudo exchange-connected terminal associated with second one of the exchange-connected terminals by using the first user identification information to be used in the pseudo exchange-connected terminal, transfer the communication session start request to the pseudo exchange-connected terminal; the pseudo exchange-connected terminal may be adopted to, upon receiving the transferred communication session start request, transfer the communication session start request to the pseudo external terminal &amp; pseudo exchange-connected terminal; the pseudo external terminal &amp; pseudo exchange-connected terminal may be adopted to, upon receiving the transferred communication session start request, retrieve the second user identification information associated with the first user identification information contained in the communication session start request, from the database, and transmit a communication session start request containing the retrieved second user identification information to a pseudo external terminal associated with the first exchange-connected terminal; and the pseudo external terminal may be adopted to, upon receiving the communication session start request containing the second user identification information, transfer the communication session start request to the external server.  
         [0027]     In the exchange system, the external terminals may be adopted to be associated respectively with the exchange-connected terminals; the pseudo external terminal may be adopted to, upon receiving from a first external terminal via the external server a communication session start request which designates, as an opposite party of communication, a pseudo external terminal associated with a second external terminal by using the second user identification information to be used in the pseudo external terminal, transfer the communication session start request to the pseudo external terminal &amp; pseudo exchange-connected terminal; the pseudo external terminal &amp; pseudo exchange-connected terminal may be adopted to, upon receiving the transferred communication session start request, retrieve the first user identification information associated with the second user identification information contained in the communication session start request, from the database, and transmit the communication session start request containing the retrieved first user identification information to a pseudo exchange-connected terminal associated with the first external terminal; the pseudo exchange-connected terminal associated with the first external terminal may be adopted to, upon receiving the communication session start request, transfer the communication session start request to the exchange server; and the exchange server may be adopted to, upon receiving the transferred communication session start request, transfer the communication session start request to an exchange-connected terminal associated with the second external terminal.  
         [0028]     In the exchange system, the pseudo exchange-connected terminals, the pseudo external terminals, the database, and the pseudo external terminal &amp; pseudo exchange-connected terminal may be included in an exchange.  
         [0029]     In the exchange system, the pseudo exchange-connected terminals, the database, and the pseudo external terminal &amp; pseudo exchange-connected terminal may be included in an exchange, and the pseudo external terminals may be included in the exchange-connected terminals.  
         [0030]     Even if the user logs in only one of the external IM server and the exchange, terminals of both external IM server and terminals of the exchange are notified of the presence information of the user according to the present invention. Terminals of the two kinds are used simultaneously and the presence information is conveyed to the necessary opposite party without conducting presence alteration operation on both terminals. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]      FIG. 1  is a block diagram showing a communication exchange according to an embodiment of the present invention and an apparatus group connected to the communication exchange;  
         [0032]      FIG. 2  is a block diagram showing a configuration of the communication exchange shown in  FIG. 1 ;  
         [0033]      FIG. 3  is a block diagram showing a configuration of an exchange-connected terminal shown in  FIG. 1 ;  
         [0034]      FIG. 4  is a block diagram showing modules and a database included in an exchange software shown in  FIG. 2 ;  
         [0035]      FIG. 5  is a diagram showing a configuration of a table and a data example included in the database shown in  FIG. 4 ;  
         [0036]      FIG. 6  is a sequence diagram showing a first method of a presence alteration notice according to an embodiment of the present invention;  
         [0037]      FIG. 7  is a sequence diagram showing a second method of a presence alteration notice according to an embodiment of the present invention;  
         [0038]      FIG. 8  is a sequence diagram showing a first method of address book synchronization according to an embodiment of the present invention;  
         [0039]      FIG. 9  is a sequence diagram showing a second method of address book synchronization according to an embodiment of the present invention;  
         [0040]      FIG. 10  is a sequence diagram showing a first method of communication session establishment according to an embodiment of the present invention; and  
         [0041]      FIG. 11  is a sequence diagram showing a second method of communication session establishment according to an embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0042]     Hereafter, embodiments of the present invention will be described in detail with reference to the drawings.  
         [0043]     The IM server is opened to a large-scaled public with ordinary consumers regarded as users. On the other hand, communication systems intended for enterprises, such as KTSs (key telephone systems) and PBXs, on which an apparatus having a function similar to that of the IM server is mounted, have increased recently. The IM server has a merit that communication with worldwide subscribers can be conducted. The communication system intended for enterprises has a groupware function, a multi-line function and reliability with due regard to business use. Since a server is disposed within one&#39;s own company in principle, the communication system intended for enterprises has a merit that secret information can be protected.  
         [0044]     Traditionally, separate terminals must be prepared to enjoy merits of both the IM server and the communication system intended for enterprises. In that case, the presence/address book is not synchronized between terminals of them and communication cannot be conducted between the terminals of them, resulting in inconvenience. The present invention implements a communication system intended for enterprises which operates in cooperation with the IM server intended for ordinary consumers.  
         [0045]     With reference to  FIG. 1 , a communication exchange (hereafter referred to as “exchange”)  102  which conducts exchange of communication such as telephone, E-mails, or instant messages (hereafter referred to as “IM”) and exchange-connected terminals  103  connected to the exchange  102  are included in an office  101 .  
         [0046]     An office LAN  104  is connected to the Internet  106  via a gateway  105 . Beyond the Internet  106 , there are an IM server  107  for consumers (hereafter referred to as “external IM server”) and external instant message terminals (hereafter referred to as “IM terminals”)  108  of the external IM server  107 . If the user requests presence information alteration or communication session by operating an exchange-connected terminal  103 , it is conveyed to the exchange  102 . The exchange  102  conveys its information to the external IM server  107 , and the external IM server  107  conveys its information to the external IM terminal  108 . If the user requests presence information alteration or communication session by operating the external IM terminal  108 , it is first conveyed to the external IM server  107 , and conveyed from the external IM server  107  to the exchange  102 . The exchange  102  conveys its information to an exchange-connected terminal  103 . In this way, exchange of presence information and establishment of the communication session can be conducted between the terminals  103  and  108 .  
         [0047]     In this way, it becomes possible for the user to receive IM service intended for ordinary consumers and IM service intended for enterprises simultaneously by using one terminal application.  
         [0048]     With reference to  FIG. 2 , respective units in the exchange operate as described roughly below. A LAN I/F unit  102 - 1  conducts data transmission and reception on the office LAN  104 . A CPU  102 - 2  executes general control on the exchange  102 . A memory  102 - 3  stores data required to control the exchange  102 . Exchange software  102 - 4  is stored in the memory  102 - 3 . The exchange software  102 - 4  is a software for general control of the exchange  102 , and is executed by the CPU  102 - 2 .  
         [0049]     With reference to  FIG. 3 , respective units in the exchange-connected terminal  103  operate as described roughly below. A keyboard I/F unit  103 - 1  receives an input signal from a keyboard. A mouse I/F unit  103 - 2  receives an input signal from a computer mouse. A display I/F unit  103 - 3  outputs a picture signal to a display. A LAN I/F unit  103 - 4  transmits a signal to or receives a signal from the office LAN  104 . A CPU  103 - 5  controls the whole exchange-connected terminal  103 . A memory  103 - 6  stores software used to control the whole exchange-connected terminal  103  and necessary data. The software is executed by the CPU  103 - 5 .  
         [0050]      FIG. 4  shows a module configuration of the exchange software  102 - 4  stored in the memory  102 - 3  in the exchange. Here, the module means, for example, an instance generated on the basis of a class expressed in an object-oriented programming language.  
         [0051]     An exchange server module  401  receives information from each terminal, and issues an order. A pseudo exchange-connected terminal module  402  is a pseudo module which conducts operation similar to that conducted by software in the exchange-connected terminal  103  connected to the exchange  102 . As occasion demands, a plurality of pseudo exchange-connected terminal modules  402  are generated. A pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  is a module obtained by combining a pseudo model which conducts operation similar to that conducted by software in the exchange-connected terminal  103  with a pseudo model which conducts operation similar to that conducted by software in the external IM terminal  108 . In principle, only one pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  is generated. A pseudo IM terminal module  404  is a pseudo module which conducts operation similar to that conducted by software in the external IM terminal  108 . As occasion demands, a plurality of pseudo IM terminal modules  404  are generated. A database  405  stores user account information of users using the exchange-connected terminals  103 , personal address books used respectively by the users, and a shared address book used by all the users.  
         [0052]     The pseudo exchange-connected terminal modules  402  are provided so as to be respectively associated with the external IM terminals  108 . The pseudo IM terminal modules  404  are provided so as to be respectively associated with the exchange-connected terminals  103 . Each user owns one exchange-connected terminal  103  and one external IM terminal  108 . Therefore, the exchange-connected terminals  103  are respectively associated with the external IM terminals  108 . As a result, the exchange-connected terminals  103 , the external IM terminals  108 , the pseudo exchange-connected terminal modules  402 , and the pseudo IM terminal modules  404  have a relation of 1:1:1:1.  
         [0053]      FIG. 5  shows a table provided in the database  405  shown in  FIG. 4  to store account information of users and personal and shared address books. In each record in this table, an exchange user ID  501  is an ID to be used by the exchange server module  401  to identify an exchange-connected terminal  103 . An exchange user password  502  is a password associated with an exchange user ID. An IM user ID  503  is an ID to be used when a user having the exchange user ID logs in the external IM server  107 . An IM user password  504  is a password associated with an IM user ID. Personal address book data  505  is address book data to be used by the user on the exchange-connected terminal  103 . Shared address book data  506  is shared address book data to be used by all the users in common.  
         [0054]     Operation of the present embodiment will now be described specifically.  
         [0055]     First, a method for synchronizing presences between the exchange  102  and the external IM server  107  will now be described with reference to  FIGS. 6 and 7 .  
         [0056]     It is supposed that the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  has a dedicated ID for external IM client, and previously registers IM user IDs  503  of all the records in the table in the database  405  in the exchange  102  with the external IM server  107  as a Buddy list. Simultaneously with starting the exchange  102 , the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  conducts logging in the external IM server  107  and logging in the exchange server module  401 . Therefore, if the user has conducted login or presence alteration via an external IM terminal  108 , then the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  can receive the information on it from the external IM server  107 , and if the user has conducted login or presence alteration via an exchange-connected terminal  103 , then the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  can receive the information on it from the exchange server module  401 .  
         [0057]     With reference to  FIG. 6 , if a user conducts presence alteration operation on an exchange-connected terminal  103  (step S 201 ), a notice of the alteration operation is sent to the CPU  103 - 5  by the keyboard I/F unit  103 - 1  or the mouse I/F unit  103 - 2  according to the operation device. The CPU  103 - 5  sends a notice of the presence alteration to the exchange  102  via the LAN I/F unit  103 - 4  (step S 203 ). An exchange user ID is contained in this notice.  
         [0058]     A notice of presence alteration is sent to the exchange server module  401  in the exchange software  102 - 4  via the LAN I/F unit  102 - 1  in the exchange  102 . The exchange server module  401  sends a notice of the information to all the logged in exchange-connected terminals  103 , all the logged in pseudo exchange-connected terminal modules  402  and the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  (step S 205 ). Therefore, the notice of presence alteration is sent to the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  as well.  
         [0059]     Upon receiving the presence alteration notice, the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  locates an, exchange user ID contained in the notice, from the table in the database  405 , and acquires an IM user ID  503  and an IM user password  504  of a hit entry (steps S 207  and S 209 ). And the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  adds the IM user ID  503  and the IM user password  504  to the presence alteration notice, and transmits the presence alteration notice having the IM user ID and the IM user password associated with the exchange-connected terminal  103  on which the presence alteration operation has been conducted, to a pseudo IM terminal module  404  associated with the exchange-connected terminal  103  on which the presence alteration operation has been conducted (step S 211 ).  
         [0060]     Unless logged in, the pseudo IM terminal module  404  logs in the external IM server  107  by using the received IM user ID and password (step S 213 ). Thereafter, the pseudo IM terminal module  404  notifies the external IM server  107  that its own presence has been altered to via the LAN I/F unit  102 - 1 , the office LAN  104 , the gateway  105 , and the Internet  106  (step S 215 ). Upon receiving the notice, the external IM server  107  sends out a presence alteration notice to the external IM terminals  108  which register the user conducted the presence alteration operation with the Buddy list of them (step S 217 ).  
         [0061]     With reference to  FIG. 7 , if a user conducts presence alteration operation on an external IM terminal  108  (step S 221 ), a presence alteration notice is transmitted to the external IM server  107  (step S 223 ). An external IM user ID is contained in this notice.  
         [0062]     The external IM server  107  transfers the presence alteration notice to all the logged in external IM terminals  108 , all the logged in pseudo IM terminal modules  404 , and the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  (step S 225 ). Therefore, the presence alteration notice is sent to the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  in the exchange software  102 - 4  via the Internet  106 , the gateway  105 , the office LAN  104 , and the LAN I/F unit  102 - 1 .  
         [0063]     Upon receiving the notice, the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  conducts retrieval in the table included in the database  405  by using the external IM user ID contained in the notice, and acquires the exchange user ID  501  and the exchange user password  502  of the hit entry (steps S 227  and S 229 ). And the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  transmits the presence alteration notice with the retrieved exchange user ID  501  and the exchange user password  502  to the pseudo exchange-connected terminal module  402  which is associated with the external IM terminal  108  on which the user conducts presence alteration operation (step S 231 ).  
         [0064]     Unless logged in, the pseudo exchange-connected terminal module  402  logs in the exchange server module  401  (step S 233 ). Thereafter, the pseudo exchange-connected terminal module  402  notifies to the exchange server module  401  that its own presence has been altered (step S 235 ).  
         [0065]     Upon receiving the notice, the exchange server module  401  notifies the presence alteration to the exchange-connected terminals (S 237 ).  
         [0066]     A method for synchronizing a personal address book and an external address book will now be described with reference to  FIG. 8 .  
         [0067]     With reference to  FIG. 8 , if a user conducts login operation on an exchange-connected terminal  103  (step S 241 ), a notice of the login operation is sent to the CPU  103 - 5  by the keyboard I/F unit  103 - 1  or the mouse I/F unit  103 - 2  according to the operation device. The CPU  103 - 5  sends a login notice to the exchange  102  via the LAN I/F unit  103 - 4  (step S 243 ). An exchange user ID input to the logged in exchange-connected terminal  103  is contained in the login notice. A login notice is sent to the exchange server module  401  in the exchange software  102 - 4  via the LAN I/F unit  102 - 1  in the exchange  102 .  
         [0068]     The exchange server module  401  transmits a login notice to all the logged in exchange-connected terminals  103 , all the logged in pseudo exchange-connected terminal modules  402  and the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  (step S 245 ). Therefore, the login notice is sent to the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  as well.  
         [0069]     Upon receiving the notice, the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  locates an exchange user ID contained in the login notice, from the table in the database  405 , and acquires an IM user ID  503  and an IM user password  504  of a hit entry (steps S 247  and S 249 ). And the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  transmits a login notice with the IM user ID  503  and the IM user password  504  to a pseudo IM terminal module  404  associated with the IM user ID (step S 251 ).  
         [0070]     The pseudo IM terminal module  404  logs in the external IM server  107  via the LAN I/F unit  102 - 1 , the office LAN  104 , the gateway  105  and the Internet  106  by using the received IM user ID and password (step S 253 ).  
         [0071]     Thereupon, the external IM server  107  sends the login notice to the external IM terminals  108  which register the user conducted the login operation with the Buddy list of them (step S 255 ). In addition, the external IM server  107  transmits an external address book (Buddy list) of the user conducted the login operation in the external IM server  107  to the logged in pseudo IM terminal module  404  (step S 257 ).  
         [0072]     Upon receiving the external address book data, the pseudo IM terminal module  404  locates the IM user ID  503  in the database  405  in the exchange which is the same as the IM user ID of the logged in user, and acquires the personal address book data  505  of the hit entry (steps S 259  and S 261 ).  
         [0073]     Thereafter, the pseudo IM terminal module  404  synchronizes both the acquired address book data, i.e., the external address book data and the personal address book data  505  (step S 263 ). As the synchronization algorithm, a typical algorithm can be applied.  
         [0074]     For example, it is possible to apply an algorithm which gives priority to one of the address books, an algorithm which does not give priority to any address book and which gives priority to a record having later update date when contraction has occurred, or an algorithm which does not give priority to any address book and which urges the user to select data to be given priority when contraction has occurred.  
         [0075]     After the synchronization has been completed, the pseudo IM terminal module  404  stores the address book data in the pertinent entry of the personal address book data  505  of the database  405  and stores the address book data in the external IM server  107  (steps S 265 , S 267 , S 269  and S 271 ).  
         [0076]     According to the embodiment, it becomes possible to use a unified address book no matter to which of the external IM server  107  and the exchange  102  the user is logged in, and the trouble of administering separate address books respectively in terminals of the two kinds is eliminated.  
         [0077]     A method for synchronizing a personal address book and an external address book and then synchronizing the shared address book and the external address book will now be described with reference to  FIG. 9 . Here, “synchronizing a personal address book and an external address book” means making contents of them the same. However, “synchronizing the shared address book and an external address book” means that changes in the shared address book are reflected to the external address book, but contents of the shared address book are not altered.  
         [0078]     Steps S 241  to S 267  are the same as those in the case where only synchronization of the personal address book and the external address book is conducted.  
         [0079]     Subsequently to the step S 267 , the pseudo IM terminal module  404  acquires the shared address book  506  from the database  405  (steps S 281  and S 283 ).  
         [0080]     Subsequently, the pseudo IM terminal module  404  synchronizes the external address book and shared address book (step S 285 ), and transmits an external address book update request to the external IM server  107  (step S 287 ). The external IM server  107  updates the external address book in response to the request (step S 289 ).  
         [0081]     As a result, it becomes possible to use the shared address book which has been traditionally used only in exchanges intended for enterprises, even when a user logs in the external IM server for which users are many and unspecified ordinary consumer users and there is not a concept of shared address book. It becomes possible to administer address books unitarily.  
         [0082]     A method for establishing a communication session (such as talking, an IM, or application sharing) between the external IM terminal  108  and the exchange-connected terminal  103  will now be described with reference to  FIGS. 10 and 11 .  
         [0083]     With reference to  FIG. 10 , if a user conducts communication session start operation on an exchange-connected terminal  103  (step S 301 ), a notice of the communication session start request is sent to the CPU  103 - 5  by the keyboard I/F unit  103 - 1  or the mouse I/F unit  103 - 2  according to the operation device. The CPU  103 - 5  sends a notice of the communication session start request to the exchange  102  via the LAN I/F unit  103 - 4  (step S 303 ). An exchange user ID of the exchange-connected terminal that has issued the communication session start request and an exchange user ID of an exchange-connected terminal associated with an external IM terminal  108  that will receive the communication session start request are contained in the communication session. A notice of the communication session start request is sent to the exchange server module  401  in the exchange software  102 - 4  via the LAN I/F unit  102 - 1  in the exchange  102 .  
         [0084]     The exchange server module  401  sends a notice of the information to a pseudo exchange-connected terminal module  402  logged in with an account of the opposite party of communication (step S 305 ).  
         [0085]     The pseudo exchange-connected terminal module  402  sends a notice of the request to the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  (step S 307 ).  
         [0086]     Upon receiving the notice, the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  locates an exchange user ID of the communication request origin contained in the notice from the table in the database  405 , and acquires an IM user ID  503  and an IM user password  504  (IM user ID of the communication request origin and IM password of the communication request origin) of a hit entry. In addition, the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  locates an exchange user ID of the communication request destination contained in the notice from the table in the database  405 , and acquires an IM user ID  503  (IM user ID of the communication request destination) of a hit entry (steps S 309  and S 311 ). And the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  transmits a communication session start request with the IM user ID of the communication request origin and the password of the communication request origin and the IM user ID of the communication request destination added thereto, to a pseudo IM terminal module  404  associated with the exchange-connected terminal  103  of the communication request origin (step S 313 ).  
         [0087]     Unless logged in, the pseudo IM terminal module  404  logs in the external IM server  107  by using the received IM user ID and password of the communication request origin (step S 315 ). While using the address of the exchange-connected terminal  103  of the communication request origin as the address of the communication request origin, the pseudo IM terminal module  404  sends a notice of a communication session start request directed to the external IM terminal of the communication opposite party, to the external IM server  107  via the LAN I/F unit  102 - 1 , the office LAN  104 , the gateway  105  and the Internet  106  (step S 317 ).  
         [0088]     Upon receiving the notice of the communication session start request, the external IM server  107  sends a communication session start request to the external IM terminal  108  of the communication opposite party (step S 319 ).  
         [0089]     Upon receiving the communication session start request, the external IM terminal  108  of the communication opposite party establishes the communication session by sending a notice of communication session acknowledge to the exchange-connected terminal  103  of the communication start request origin contained in the request (step S 321 ).  
         [0090]     With reference to  FIG. 11 , if a user conducts communication session start operation on an external IM terminal  108  (step S 331 ), the external IM terminal  108  sends a notice of a communication session start request to the external IM server  107  (step S 333 ). An IM user ID of the external IM terminal  108  of the request origin and an IM user ID associated with the exchange-connected terminal  103  of the request destination are contained in the communication session start request.  
         [0091]     The external IM server  107  transfers the communication session start request to a pseudo IM terminal module  404  having the IM user ID associated with the exchange-connected terminal  103  of the request destination (step S 335 ). The notice of the communication session start request is sent to a pseudo IM terminal module  404  of communication opposite party in the exchange software  102 - 4  via the LAN I/F unit  102 - 1  in the exchange  102 .  
         [0092]     Upon receiving the notice of the communication session start request, the pseudo IM terminal module  404  sends the notice of the request to the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  (step S 337 ).  
         [0093]     The pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  retrieves an exchange user ID associated with the IM user ID of the external IM terminal  108  of the communication request origin and an exchange user ID associated with the IM user ID which is in turn associated with the exchange-connected terminal  103  of the request destination, from the table in the database  405  (steps S 339  and S 341 ).  
         [0094]     Subsequently, the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403  transmits the request to a pseudo exchange-connected terminal module  402  logged in with an account of the exchange user of the communication start request origin (step S 343 ).  
         [0095]     The pseudo exchange-connected terminal module  402  uses the address of the external IM terminal of the communication request origin as the address of the communication request origin, and sends a notice of a communication session start request directed to the exchange-connected terminal  103  of the communication opposite party, to the exchange server module  401  (step S 345 ).  
         [0096]     Upon receiving the notice of the communication session start request, the exchange server module  401  sends a communication session start request to the exchange-connected terminal  103  of the communication opposite party (step S 347 ).  
         [0097]     Upon receiving the communication session start request, the exchange-connected terminal  103  of the communication opposite party establishes a communication session with the external IM terminal  108  of the communication start request origin contained in the request, and transmits communication session acknowledge to the external IM terminal of the communication request origin via the exchange server module  401 , the pseudo exchange-connected terminal module  402 , the pseudo IM terminal &amp; pseudo exchange-connected terminal module  403 , the pseudo IM terminal module  404  and the external IM server  107  (step S 349 ).  
         [0098]     No matter to which of the exchange  102  and the external IM server  107  a user belongs, therefore, the user can establish a communication session with both terminals.  
         [0099]     Another embodiment of the present invention will now be described.  
         [0100]     In the above-described embodiment, the pseudo IM terminals are included in the exchange software  102 - 4  in the exchange server  102 . Alternatively, the pseudo IM terminals may be included respectively in the exchange-connected terminals  103 , and login/logout of a pseudo IM terminal to the external IM server  107  may be altered manually in the exchange-connected terminals  103 .  
         [0101]     In this case, unlike the above-described embodiment, the pseudo IM terminal module  404  is moved into the memory  103 - 6  in the exchange-connected terminal  103 , and it is obviated that unless logged in the pseudo IM terminal module  404  automatically logs in at the step S 213  shown in  FIG. 6 , the step S 253  shown in  FIG. 8 , and the step S 315  shown in  FIG. 10 . Unless a pseudo IM terminal module  404  is manually logged in even if an exchange-connected terminal user logs in an exchange-connected terminal, it is inhibited to conduct presence synchronization, the address book synchronization, and the communication session establishment with the external IM server  107  and the external IM terminal  108 .  
         [0102]     When it is desired for the pseudo IM terminal module  404  to log in or log out the external IM server  107 , a notice of a login or logout request is sent to the CPU  103 - 5  together with the ID and password for the external IM server  107  by the keyboard I/F unit  103 - 1  or the mouse I/F unit  103 - 2  in response to operation of an operation device on the exchange-connected terminal  103 . The CPU  103 - 5  sends a notice of the pseudo IM terminal login or logout request, the ID and password to the pseudo IM terminal module  404  in the memory  103 - 6 . The pseudo IM terminal module  404  sends a login or logout notice to the external IM server  107  by using the ID and password via the LAN I/F unit  103 - 4 , the office LAN  104 , the gateway  105 , and the Internet  106 .  
         [0103]     As a result, it becomes possible for the exchange-connected terminal  103  to turn on or off cooperation with the external IM server  107  as occasion demands, in such a case where it is desired to shut out communication with an acquaintance via the external IM server  107  because of important work being held.  
         [0104]     The present invention can be used to share presence information, make address books uniform, and conduct communication between a terminal connected to a system and a terminal connected to another system.