Abstract:
The present invention provides an exchange system which makes it possible to control connection and disconnection between terminals by an operation method which can be intuitively recognized. The exchange system includes display means for displaying icons of various terminals on screens of the terminals, detection means for detecting association between the icons performed on the screens of the terminals, and control means for controlling connection and disconnection between the terminals and/or connection and disconnection between an exchange apparatus and the terminals depending on the contents of the association.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an exchange system and an exchange method, and more particularly, to an exchange system and an exchange method which connect extension terminals to each other and connect an extension terminal to an outside terminal. 
   2. Description of the Related Art 
   In a conventional telephone exchange and the like, when a connection change operation (e.g., transfer) is performed, the following button operations are required. That is, (1) a hold button is depressed, (2) a destination is dialed, and (3) a transfer button is depressed. 
   When a function is allocated to a button such as a short-cut key, a function button, and a one-touch button, one function can be executed by depressing one button once. However, in order to realize this, a user must perform a registration operation such as short-cut key allocation in advance. Since one button is occupied for one function, a large number of buttons are required, and a long period of time is required to search for a button to which a specific function is allocated, or an erroneous button is depressed. In a television conference system and the like, the following button operations are required. That is, (1) a button is depressed, (2) menu  1  is selected, and (3) menu  2  is selected. A long period of time is required to search for a target function. 
   In terminals and the like of a conventional telephone exchange, when a plurality of terminals, outside lines, devices transmit calls to a terminal and are connected to the terminal, it is very difficult for the terminal to recognize all of these. For this reason, the terminal cannot respond to an important incoming call. 
   For example, when incoming calls from a plurality of terminals or outside lines are received by a terminal, in order for the terminal to recognize the terminals which transmit the calls, only pieces of information of one or two of the terminals or lines are displayed, or an information display of a currently connected destination is concealed by an incoming information display. Furthermore, the displayed information is displayed with characters of telephone numbers, extension numbers, names, and types, so that an entire connection relation cannot be visually understood. 
   In a conventional telephone exchange and the like, in order to change a connection state between a certain terminal and an outside line or a device, the terminal must be operated, and the connection state cannot be easily managed and changed by a related terminal, a dedicated management terminal, and the like. A terminal is imaginary posed as the terminal, or a dedicated function must be mounted on the exchange apparatus. 
   SUMMARY OF THE INVENTION 
   The present invention has been made in consideration of the above disadvantages, and has an object to provide an exchange system and an exchange method which make it possible to control connection and disconnection, and the like between terminals by an operation method which can be intuitively recognized. According to an aspect of the present invention, there is provided an exchange system comprising: display means for displaying icons of various terminals on screens of terminals; detection means for detecting association between the icons performed on the screens of the terminals; and control means for controlling connection and disconnection between the terminals and/or connection and disconnection between an exchange apparatus and the terminal depending on the contents of the association. 
   The exchange system may further comprise: means for displaying an icon of a destination terminal and an icon of a registered terminal on the screens of the terminals; means for detecting that an association operation between the icon of the destination terminal and the icon of the registered terminal serving as a second terminal is performed on the screen of a first terminal; and means for generating a call from the first terminal to the second terminal when the association operation between the icon of the destination terminal and the icon of the registered terminal serving as the second terminal is detected. 
   The exchange system may further comprise: means for displaying an icon of a destination terminal and an icon of a call originating terminal on the screens of the terminals; means for activating the icon of the call originating terminal displayed on the screen of the second terminal when a call sent from the first terminal to the second terminal is generated; means for detecting that an association operation between the icon of the destination terminal and the icon of the call originating terminal is performed on the screen of the second terminal; and means for establishing connection between the first terminal and the second terminal when the association operation between the icon of the destination terminal and the icon of the call originating terminal is detected on the screen of the second terminal. 
   The exchange system may further comprise: means for displaying the icon of the destination terminal and an icon of a holding terminal on the screens of the terminals; means for detecting that an association operation between the icon of the destination terminal and the icon of the holding terminal is performed on a screen of a certain terminal; and means for setting the certain terminal in a telephone call holding state when the association operation between the icon of the destination terminal and the icon of the holding terminal is detected on the screen of the certain terminal. 
   In the exchange system, the icon of the holding terminal may be increased to a plurality of icons of the holding terminals, and a melody used in the holding state may be changed depending on the icon of the holding terminal associated with the icon of the destination terminal. 
   The exchange system may further comprise: means for displaying an icon of a destination terminal and an icon of a holding terminal on the screens of the terminals; means for detecting that an association operation between the icon of the destination terminal and the icon of the holding terminal is performed on a screen of a certain terminal; and means for connecting a holding destination terminal and a destination terminal which is communicating with the certain terminal when the association operation between the icon of the destination terminal and the icon of the holding terminal is detected on the screen of the certain terminal. 
   The exchange system may further comprise: means for displaying an icon of a destination terminal, an icon of a self-terminal, and a graphic connecting the icon of the destination terminal and the icon of the self terminal on the screens of the terminals; means for detecting that the graphic is operated on a screen of a certain terminal; and means for switching a telephone call direction between the certain terminal and a destination terminal with which the certain terminal communicates when the graphic is operated on the screen of the certain terminal. 
   The exchange system may further comprise: means for displaying an icon of a call originating terminal and an icon of a recording terminal on the screens of the terminals; means for detecting that an association operation between the icon of the call originating terminal and the icon of the recording terminal is performed on a screen of a certain terminal; and means for recording voice from the call originating terminal when the association operation between the icon of the call originating terminal and the icon of the recording terminal is detected on the screen of the certain terminal. 
   The exchange system may further comprise: means for displaying an icon of a call originating terminal and an icon of a recording device on the screens of the terminals; means for detecting that an association operation between the icon of the call originating terminal and the icon of the recording device is performed on a screen of a certain terminal; and means for recording voice from the call originating terminal when the association operation between the icon of the call originating terminal and the icon of the recording device is detected on the screen of the certain terminal. 
   The exchange system may further comprise: means for displaying an icon of a destination terminal and an icon of a recording device on the screens of the terminals; means for detecting that an association operation between the icon of the destination terminal and the icon of the recording device is performed on a screen of a certain terminal; and means for recording voice of telephone conversation between the certain terminal and the destination terminal with which the certain terminal communicates when the association operation between the icon of the destination terminal and the icon of the recording device is detected on the screen of the certain terminal. 
   In the exchange system, the control means may comprise means for transmitting a connection request message from the terminals to the exchange apparatus, said connection request message including a connection request table having source information, destination information, and a connection direction depending on the contents of association detected by the detection means. 
   In the exchange system, the exchange apparatus may comprise means for updating, on the basis of the contents of the connection request table included in the connection request message received from the terminals and the contents of a current connection information table, the contents of the connection information table. 
   In the exchange system, the exchange apparatus may further comprise means for transmitting a connection table updating notice message including the updated connection information table to a related terminal. 
   In the exchange system, each of the terminals may comprise means for updating a display of the screen on the basis of the connection information table included in the connection table updating notice message received from the exchange apparatus. 
   In the exchange system, when a plurality of terminals receive data of the same contents from the exchange apparatus, only a piece of data may be transmitted from the exchange apparatus to the extension line. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a first sequence diagram showing an operation of a media exchange system according to an embodiment of the present invention; 
       FIG. 2  is a second sequence diagram showing an operation of the media exchange system according to the embodiment of the present invention; 
       FIG. 3  is a block diagram showing the internal configuration or the like of an exchange apparatus according to the embodiment of the present invention; 
       FIG. 4  is a block diagram showing the internal configuration of a terminal according to the embodiment of the present invention; 
       FIG. 5  is a diagram showing the configuration of a screen displayed by the terminal according to the embodiment of the present invention; 
       FIG. 6  is a diagram of a first screen displayed when two-sided communication is performed by terminals according to the embodiment of the present invention; 
       FIG. 7  is a diagram of a second screen displayed when two-sided communication is performed by terminals according to the embodiment of the present invention; 
       FIG. 8  is a diagram showing a structure of a connection request table according to the embodiment of the present invention; 
       FIG. 9  is a diagram of a third screen displayed when two-sided communication is performed by the terminals according to the embodiment of the present invention; 
       FIG. 10  is a diagram of a first screen displayed when transfer is performed by the terminal according to the embodiment of the present invention; 
       FIG. 11  is a diagram of a second screen displayed when transfer is performed by the terminal according to the embodiment of the present invention; 
       FIG. 12  is a diagram of a third screen displayed when transfer is performed by the terminal according to the embodiment of the present invention; 
       FIG. 13  is a diagram of a fourth screen displayed when transfer is performed by the terminal according to the embodiment of the present invention; 
       FIG. 14  is a diagram of a fifth screen displayed when transfer is performed by the terminal according to the embodiment of the present invention; 
       FIG. 15  is a diagram of a sixth screen displayed when transfer is performed by the terminal according to the embodiment of the present invention; 
       FIG. 16  is a diagram of the first screen displayed when a connection direction is switched by the terminal according to the embodiment of the present invention; 
       FIG. 17  is a diagram of the second screen displayed when the connection direction is switched by the terminal according to the embodiment of the present invention; 
       FIG. 18  is a diagram of the third screen displayed when the connection direction is switched by the terminal according to the embodiment of the present invention; 
       FIG. 19  is a diagram of the fourth screen displayed when the connection direction is switched by the terminal according to the embodiment of the present invention; 
       FIG. 20  is a diagram of the first screen displayed when a message from an answerphone is transferred by the terminal according to the embodiment of the present invention; 
       FIG. 21  is a diagram of the second screen displayed when a message from an answerphone is transferred by the terminal according to the embodiment of the present invention; 
       FIG. 22  is a diagram of the first screen displayed when telephone conversation recording is performed by the terminal according to the embodiment of the present invention; and 
       FIG. 23  is a diagram of the second screen displayed when a telephone call is recorded by the terminal according to the embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   According to the present invention, a media exchange apparatus such as a telephone exchange and a server which performs connection control between terminals such as telephones, mobile telephones, personal computers (PC), and mobile information terminals (PDA) is provided. The terminals notice only destination change information of respective terminals to the exchange apparatus to make it possible to change a destination terminal by an easy operation method such as a drag-and-drop operation on the terminals, without a conventional input operation of entering a specific number designated to each function to a terminal or a plurality of button operations. In addition, connection information is transmitted from the exchange apparatus to a terminal (or a remote management device and the like) to make it possible to easily recognize the connection information on the terminal (or the remote management device and the like). 
     FIG. 1  is a conceptual diagram showing a sequence of connection. 
   Referring to  FIG. 1 , a terminal B transmits a connection request table which describes a request to connect the terminal B to a terminal A to an exchange apparatus  111  (step S 21 ). Then, the exchange apparatus  111  transmits a signal to a terminal A (step S 22 ) to check whether a response is replied from the terminal A (step S 23 ). Next, the exchange apparatus  111  performs a connection process to the terminals A and B (step S 24 ). Finally, the exchange apparatus  111  updates a current connection information table  14  and transmits the notice of updating of the connection information table to the terminal A and B (step S 25 ). A display of the information of the connection information table is updated together with the information of the connection information table  14 . In the example in  FIG. 1 , the terminal B and the terminal A are connected to each other by the request from the terminal B. However, the terminal B may be connected to two or more terminals, and the two or more terminals except for the terminal B may be connected to each other by the request from the terminal B. 
     FIG. 2  is a conceptual diagram showing a sequence of disconnection. 
   The exchange apparatus  111  performs a disconnection process to the terminals A and B (step  32 ). Finally, the exchange apparatus  111  updates the current connection information table  14  and transmits the notice of updating of the connection information table to the terminals A and B (step S 33 ). 
     FIG. 3  shows the entire configuration of the exchange apparatus  111  according to this embodiment and terminals  101  to  103  connected to the exchange apparatus  111 . The exchange apparatus  111  is a telephone exchange, a server, and the like to control connection of media. 
   Reference numeral  106  denotes an extension interface; L 11 , an exchange apparatus internal circuit;  105 , a CPU for entirely controlling the exchange apparatus  111 ;  104 , a memory for storing a program executed by the CPU  105  and a current connection information table;  109 , an outside line interface for controlling connection and disconnection between the terminals  101 ,  102 , and  103  and a public network line; L 12  and L 13 , outside lines connected to a public network;  110 , a storage device in which voice data and music data are stored;  107 , a reproducing device for reproducing voice data and music data stored in the storage device  110 ; and  108 , a recording device for recording voice from the terminals  101 ,  102 , and  103 , music data sent from the terminals, and the like on the storage device. 
   It is assumed that the extension number of the terminal  101  is “101”, the extension number of the terminal  102  is “102, and the extension number of the terminal  103  is “103”. It is assumed that a user name using the terminal  101  is “A”, a user name using the terminal  102  is “B”, and a user name using the terminal  103  is “C”. 
     FIG. 4  shows the internal configurations of the terminals  101 ,  102 , and  103 . Reference numeral  202  denotes an extension interface for performing communication with the exchange apparatus  111  and other terminals;  204 , a CPU for controlling whole the terminal;  203 , a memory for storing a program executed by the CPU  204  and destination information;  206 , an input device such as a mouse, a keyboard, and a button; and  205 , a control device controlling the input device  206 . Reference numeral  208  denotes a liquid-crystal display unit for displaying characters and images; and  207 , a display control unit for controlling the liquid-crystal display unit  208 . Reference numeral  209  denotes a voice input device such as a microphone;  210 , a voice output device such as a loudspeaker; and  211 , a storage device for storing music and voice. 
   The number of terminals connected to the exchange apparatus  111  depends on the processing ability of the exchange apparatus. However, the following description will be made with respect to a case in which the system accommodates three terminals. An extension line of any type may be used as an extension line L 21  for connecting the exchange apparatus  111  and the terminals  101 ,  102 , and  103 . For example, a LAN or a conventional telephone line may be used. Any terminals each having the constituent elements in  FIG. 4  may be used as the terminals  101 ,  102 , and  103 . For example, a telephone set, a personal computer, or a television set may be used. 
   In this embodiment, a telephone exchange is supposed to be an exchange apparatus, a personal computer is supposed to be a terminal, and a mouse is supposed to be the input device  206 . The embodiment will describe cases in which a two-sided communication function, a transfer function, an answerphone recording function, and a call recording function which are basic functions of the telephone exchange are performed. A mouse operation such as clicking, dragging, and dropping is detected by the control device  205 , and sent to the CPU  204  to be processed. 
     FIG. 5  shows a configuration of a screen displayed on the liquid-crystal display unit  208  of the terminal  101 ,  102 , or  103 . Reference numerals  401  to  404  denote icons of registered destinations. Either of extension and outside line can be registered as one of destinations. Reference numerals  408  to  410  denote icons representing terminals (call originating terminals) generating an incoming call received by the self-terminal. Reference numerals  405  and  406  denote icons for displaying terminals of destinations (destination terminals) for the self-terminal; and  407  denotes an icon representing the self-terminal. Reference numeral  411  denotes an icon representing a holding sound source;  412  and  413  denote icons representing terminals (holding terminals) which are listening to the holding sound source represented by the icon  411 . Reference numeral  414  denotes an icon representing a recording device; and  415  denotes an icon representing a terminal (recording terminal) which is recording a voice on the recording device represented by the icon  414 . Reference numeral  416  denotes an icon representing another recording device, and  417  denotes an icon representing a terminal which is recording a voice on the recording device represented by the icon  416 . 
   In this embodiment, updating of a screen of icons and the like and operations such as a mouse operation on a screen will be described for only the terminal  101 . A description of updating and operations of display screens in the other terminals  102  and  103  are omitted. Only notations of response operations, outgoing operations, and the like will be described with respect to the other terminals  102  and  103 . 
   The two-sided communication will be described first. The terminal  101  transmits a signal to the outside line L 12  to start communication. An initial screen of the liquid-crystal display unit  208  of the terminal  101  in this case is shown in  FIG. 6 . In the memory  203  of the terminal, source information (type: extension, telephone number  101 , name A) and destination information (type: outside line, telephone number X, name Y) are registered in advance. On this screen, the icon  401  representing a registered terminal to be a destination and the icon  407  representing a self-terminal are displayed. 
   A user of the terminal  101  drags and drops the icon  401  of the registered destination to the icon  405  of the destination terminal by using the mouse. At this time, the screen as shown in  FIG. 7  is displayed. On the screen as shown in  FIG. 7 , a unidirectional dotted arrow extending from the icon  407  representing the self-terminal  101  to the icon  405  of the destination terminal is displayed. With this display, the terminal  101  shows the user that the terminal  101  is calling the destination terminal represented by the icon  405 . 
   At this time, the CPU  204  of the terminal  101  detects a mouse operation to decide that the self-terminal  101  is performing an outgoing operation to a destination (type: outside line, telephone number X, name Y) registered with the memory  203 , and transmits a “connect request” message including a connection request tale having the table structure as shown in  FIG. 8  to the exchange apparatus  111 . At this time, source information (type: extension, telephone number  101 , name A) is stored in a column  301  in  FIG. 8 , destination information (type: outside line, telephone number X, name Y) is stored in a column  302 , and a connection direction (both directions) is stored in a column  303 . When a plurality of connection requests are transmitted, a plurality of sets of columns  301  to  303  are formed, and these sets are transmitted together with the “connection request” message. 
   The connection request table is transmitted to the memory  104  through the extension interface  106 . The CPU  105  of the exchange apparatus  111  compares the connection request table transmitted to the memory  104  with the current connection information table stored in the memory  104 . The current connection information table has the table structure as shown in  FIG. 8  like the connection request table. Since the exchange apparatus  111  has a plurality of current connection information tables constituted by the sets of columns  301  to  303 , the exchange apparatus  111  can recognize connection states of all the terminals and all the devices. At this time, there is no current connection information table because communication is not performed. Therefore, the CPU  105  accepts a connection request represented by the transmitted connection request table to execute a connection process. More specifically, destination information (type: outside line, telephone number X, name Y) of the column  302  is read. Since the type is the outside line, an idle outside line, e.g., in this case, the outside line L 12 , is captured by the external interface  109 , and the destination telephone number X is dialed. 
   When the destination responds, the exchange apparatus  111  executes a connection process between the outside line L 12  and the terminal  101 , generates a copy of the transmitted connection request table as a current connection information table, and then notices a “connection table updating notice” message including the current connection information table to the terminal  101 . The terminal  101  which receives the current connection information recognizes that a connection path is changed into a state as represented by the transmitted current connection information table, updates the screen in  FIG. 7  into a display screen as shown in  FIG. 9 , and notifies the user that two-sided communication is established. On the screen in  FIG. 9 , a bidirectional solid arrow is displayed between the icon  407  representing the self-terminal  101  and the icon  405  of the destination terminal. 
   When a user A performs a telephone conversation ending operation such as an operation of depressing an on-hook button to the terminal  101 , the terminal  101  notifies the exchange apparatus  111  that it is desired to end the telephone conversation. The exchange apparatus  111  executes a disconnection process to the outside line L 12  and the terminal  101 , writes empty data in the current connection information table, and notifies the terminal  101  of “connection table updating notice” message including the current connection information table in which the empty data is written. The terminal  101  recognizes that the telephone call is disconnected because the received current connection table is empty, and the screen in  FIG. 9  is set back to the screen as shown in  FIG. 6 . 
   Subsequently, a transfer operation will be described below. That is, a call is originated from the terminal  102  to the terminal  101 , and a telephone call between the terminal  101  and the terminal  102  is started. In the middle of the telephone call, the terminal  101  holds the telephone call and sends a signal to an outside line (type: outside line, telephone number Y, name Z) to start a telephone call. Thereafter, the terminal  102  and the outside line are connected to each other by an operation of the terminal  101 . Here, it is assumed that information (type: outside line, telephone number Y, name Z) is stored in the memory  203  of the terminal  101  in advance. 
   The terminal  102 , first, transmits a “connection request” message representing that the terminal  102  desires to be connected to the terminal  101 . Source information (type: extension, telephone number  102 , name B) is stored in the column  301  as shown in  FIG. 8  of the connection request table included in the connection request message, destination information (type: extension, telephone number  101 , name A) is stored in the column  302 , and a connection direction (both directions) is stored in the column  303 . The exchange apparatus  111  which receives the “connection request” message notifies the terminal  101  that there is a call originated from the terminal  102  to the terminal  101 . When the terminal  101  receives the notice, the self-terminal  101  updates the screen as shown in  FIG. 6  into the screen as shown in  FIG. 10  and notifies the user A that the call is received from the terminal  102 . On the screen in  FIG. 10 , a unidirectional dotted arrow extending from the icon  409  representing the terminal  102  which transmits a call to the terminal  101  to the icon  407  representing the self-terminal  101  is displayed. 
   When the user A drags and drops the icon  409  representing the terminal  102  to the icon  405  representing the destination terminal by using the mouse to perform a response operation, the terminal  101  notifies the exchange apparatus  111  that the user A recognizes the incoming call. When the exchange apparatus  111  which receives the notice performs a connection process between the terminal  101  and the terminal  102 , generates a copy of the connection request table received from the terminal  102  as a current connection table, and transmits a “connection table updating notice” message including the current connection table to the terminals  101  and  102 . The terminal  101  which receives the “connection table updating notice” message updates the screen as shown in  FIG. 10  into a screen as shown in  FIG. 11  and notifies the user A that a telephone call is established. On the screen in  FIG. 11 , a bidirectional solid arrow is displayed between the icon  407  representing the self-terminal  101  and the icon  405  representing the destination terminal  102 . 
   Thereafter, the user A drags and drops the icon  405  representing the terminal  102  to an icon  413  representing holding by using the mouse on the screen of the terminal  101  to hold the telephone call between the terminal  101  and the terminal  102 . In this case, the terminal  101  transmits a “connection request” message including a connection request table having a table structure as shown in  FIG. 8  to the exchange apparatus  111 . At this time, source information (type: extension, telephone number  102 , name B) is stored in the column  301  as shown in  FIG. 8  of the connection request table, destination information (type: holding sound source  1 , no telephone number, no name) is stored in the column  302 , and a connection direction (inverted direction) is stored in the column  303 . With respect to the connection direction, a forward direction is a direction extending from the source to the destination, and the inverted direction is a direction extending from the destination to the source. 
   When the exchange apparatus  111  receives the “connection request” message from the terminal  101 , the exchange apparatus  111  compares the connection request table included in the “connection request” message with the current connection information table, decides that the requested connection process can be executed, and executes the connection process. More specifically, the reproducing device  107  and the terminal  102  are connected to each other, and holding sound data is transmitted from the storage device  110  to the reproducing device  107 . In this manner, holding sound is output from the terminal  102 . Thereafter, a present current connection information table is replaced by the copy of the connection request table included in the “connection request” message received from the terminal  101 , and the “connection table updating notice” message including the replaced current connection information table is transmitted to the terminals  101  and  102 . When the terminal  101  receives the “connection table updating notice” message, the terminal  101  updates the screen as shown in  FIG. 11  into a screen as shown in  FIG. 12 . On the screen as shown in  FIG. 12 , the terminal  102  is displayed as the icon  413  representing a holding terminal. 
   Next, the user A drags and drops the icon  401  representing an outside terminal (type: outside line, telephone number Y, name Z) to the icon  406  representing a destination terminal by the mouse on the screen of the terminal  101  to perform an outside-line outgoing operation. The terminal  101 , then, updates the screen as shown in  FIG. 12  into a screen as shown in  FIG. 13 , and transmits a “connection request” message including a connection request table having source information (type: extension, telephone number  101 , name A) in the column  301 , destination information (type: outside line, telephone number Y, name Y) in the column  302 , and a connection direction (both directions) in the column  303  to the exchange apparatus  111 . On the screen as shown in  FIG. 13 , a unidirectional dotted arrow extending from the icon  407  representing the self-terminal  101  to the icon  406  representing the destination terminal (outside terminal) is displayed. 
   The exchange apparatus  111  which receives the “connection request” message refers to the current connection information table to check whether the destination of the terminal  101  is empty or not. The current connection information table shows that the terminal  102  and the reproducing device  107  of the exchange apparatus  111  are connected to each other. However, the current connection information table does not show that the terminal  102  is connected to any terminal and the exchange apparatus  111 . For this reason, the exchange apparatus  111  decides that a signal can be generated from the terminal  101 , captures the outside line L 12 , and dials the telephone number Y to perform an outside-line outgoing operation. When the outside line responds, the connection process between the outside line L 12  and the terminal  101  is executed. Thereafter, a copy of the connection request table received from the terminal  101  is generated as a current connection information table, and a “connection table updating notice” message including the current connection information table is transmitted to the terminal  101 . The terminal  101  which receives the “connection table updating notice” message updates the screen as shown in  FIG. 13  into a screen as shown in  FIG. 14 . On the screen as in  FIG. 14 , a bidirectional arrow is displayed between the icon  407  representing the self-terminal  101  and the icon  406  representing the destination terminal (outside terminal). 
   Thereafter, the user A drags and drops the icon  413  representing the holding terminal  102  to the icon  406  representing an outside destination communicating with the self-terminal  101  by the mouse on the screen of the terminal  101 . The terminal  101 , then, decides this operation as a transfer operation to transmit a “connection request” message including a connection request table having source information (type: extension, telephone number  102 , name B) in the column  301 , destination information (type: outside line, telephone number Y, name Z) in the column  302 , and a connection direction (both directions) in the column  303  to the exchange apparatus  111 . The exchange apparatus  111  which receives the “connection request” message compares the message with the current connection table to detect a difference therebetween. As a result, the terminal  101  is disconnected from the outside line L 12 , and the terminal  102  is connected to the outside line L 12 . Thereafter, the current connection table is updated, and a “connection table updating notice” message including the updated current connection table is transmitted to the terminals  101  and  102 . The terminal  101  which receives the “connection table updating notice” message updates the screen as shown in  FIG. 14  into a screen as shown in  FIG. 15 . On the screen in  FIG. 15 , since the terminal  102  and the outside terminal do not communicate with the terminal  101  at the present, an arrow connecting the terminal  101  and the terminal  102  and an arrow connecting the terminal  101  and the outside terminal are not displayed. 
   Next, a change in connection direction during a telephone call will be described below. It is assumed that the connection direction is sequentially changed into both directions, a forward direction, a backward direction, and muting while the terminal  101  and the terminal  102  are communicating with each other. 
   It is assumed that the terminal  101  and the terminal  102  have bidirectionally communicated with each other. At this time, the screen of the terminal  101  is as shown in  FIG. 16 . On the screen as shown in  FIG. 16 , a bidirectional arrow is displayed between the icon  407  representing the terminal  101  and the icon  405  representing the terminal  102 . 
   Here, the bidirectional arrow between the icon  407  representing the terminal  101  and the icon representing the terminal  102  is clicked by the user A by using a mouse. At this time, the terminal  101  recognizes this operation as a connection direction change operation and transmits a “connection request” message including a connection request table having source information (type: extension, telephone number  101 , name A) in the column  301 , destination information (type: extension, telephone number  102 , name B) in the column  302 , and a connection direction (forward direction) in the column  303  to the exchange apparatus  111 . When the exchange apparatus  111  receives the “connection request” message, the exchange apparatus  111  compares the connection request table included in the “connection request” message with a current connection table to detect a difference therebetween. As a result, the connection direction between the terminal  101  and the terminal  102  is changed from both directions into a forward direction. When the connection direction is changed into the forward direction, although voice at the terminal  102  is transmitted to the terminal  101 , voice at the terminal  101  is not transmitted to the terminal  102 . The exchange apparatus  111  updates the current connection table to reflect the contents of the change and then transmits the “connection table updating notice” message including the updated current connection table to the terminal  101  and the terminal  102 . When the terminal  101  receives the “connection table updating notice” message, the screen of the terminal  101  as shown in  FIG. 16  is updated into a screen as shown in  FIG. 17 . On the screen in  FIG. 17 , a unidirectional solid arrow extending from the icon  407  representing the terminal  101  to the icon  405  representing the terminal  102  is displayed. 
   The same processes as described above are performed each time the arrow between the icon  407  representing the terminal  101  and the icon  405  representing the terminal  102  is clicked on the terminal  101 . The screen of the terminal  101  is changed into a screen as shown in  FIG. 18  (backward direction) or a screen as shown in  FIG. 19  (muting). When the connection direction is set to be the backward direction, although voice at the terminal  101  is transmitted to the terminal  102 , voice at the terminal  102  is not transmitted to the terminal  101 . When the connection direction is set to be mute, the voice at the terminal  101  is not transmitted to the terminal  102 , and the voice at the terminal  102  is not transmitted to the terminal  101 , too. 
   Next, a case in which an incoming call is transferred to the recording device  108  will be described below. A call generated from the terminal  102  is received by the terminal  101 , and the terminal  101  transfers the call to the recording device  108 . 
   First, a “connection request” message which requests connection between the terminal  102  and the terminal  101  is transmitted from the terminal  102  to the exchange apparatus  111 . When the exchange apparatus  111  receives the “connection request” message, the exchange apparatus  111  transmits a message representing that the terminal  101  is called by the terminal  102  to the terminal  101 . When the terminal  101  receives the message representing that the terminal  101  is called by the terminal  102 , the terminal  101  updates the screen into a screen as shown in  FIG. 20  and notifies the user A that an incoming call generated from the terminal  102  is received. On the screen in  FIG. 20 , a unidirectional dotted arrow extending from the icon  409  representing the terminal  102  to the icon  407  representing the terminal  101  is displayed. 
   The user A cannot respond to the call request from the terminal  102  at present and intends to listen to only an essential point drags afterward. The user A drops the icon  409  representing the terminal  102  to the icon  417  representing the terminal  101  by using the mouse on the terminal  101 . Alternatively, the user A may drag or drop the icon  409  representing the terminal  102  to the icon  416  representing the recording device  108  by using the mouse on the terminal  101 . The terminal  101  transmits a “connection request” message including a connection request table having source information (type: extension, telephone number  102 , name B) in the column  301 , destination information (type: recording device  1 , no telephone number, no name) in the column  302 , and a connection direction (forward direction) in the column  303  to the exchange apparatus  111 . When the exchange apparatus  111  receives the “connection request” message, the exchange apparatus  111  decides that an incoming request from the terminal  102  to the terminal  101  is rejected to establish connection depending on the connection request message sent from the terminal  101 . More specifically, the terminal  102  is connected to the recording device  108 . In this manner, voice from the terminal  102  is stored in the storage device  110  through the recording device  108 . Upon completion of recording, the exchange apparatus  111  updates the current connection information table and transmits a “connection table updating notice” message including the updated current connection information table to the terminals  101  and  102 . When the terminal  101  receives the “connection table updating notice” message, the terminal  101  updates the screen as shown in  FIG. 20  into a screen as shown in  FIG. 21 . On the screen shown in  FIG. 21 , the recording terminal  417  is highlighted. 
   Next, a case in which telephone call recording is performed will be described below. The telephone conversation recording is to record voices of telephone conversation during a telephone call. In this case, a case in which telephone conversation between the terminal  101  and the terminal  102  is recorded by the terminal  101  will be exemplified. 
   It is assumed that the terminal  101  and the terminal  102  are set in a telephone call state. At this time, the screen of the terminal  101  is as shown in  FIG. 22 . On the screen in  FIG. 22 , a bidirectional solid arrow is displayed between the icon  407  representing the terminal  101  and the icon  405  representing the terminal  102 . 
   The user A drags and drops the icon  414  representing the recording device  108  to the icon  405  representing the terminal  102  by the mouse on the terminal  101 . The terminal  101 , then, transmits a “connection request” message including: a first connection request table having source information (type: extension, telephone number  101 , name A) in the column  301 , destination information (type: extension, telephone number  102 , name B) in the column  302 , and a connection direction (both directions) in the column  303 ; a second connection request table having source information (type: extension, telephone number  101 , name A) in the column  301 , destination information (type: recording device  1 , no telephone number, no name) in the column  302 , and a connection direction (forward direction) in the column  303 ; and a third connection request table having source information (type: extension, telephone number  102 , name B) in the column  301 , destination information (type: recording device  1 , no telephone number, no name) in the column  302 , and a connection direction (forward direction) in the column  303  to the exchange apparatus  111 . 
   When the exchange apparatus  111  receives the “connection request” message, the exchange apparatus  111  compares the three connection request tables included in the “connection request” massage with the current connection table to detect differences therebetween. The exchange apparatus  111  connects the terminal  101  and the recording device  108  to each other and connects the terminal  102  and the recording device  108  to each other. The terminal  101  and the terminal  102  have already been connected to each other. With these connections, telephone conversation between the terminal  101  and the terminal  102  is recorded on the storage device  110  by using the recording device  108 . Thereafter, the current connection table is updated to reflect the contents of the three connection request tables and transmits a “connection table updating notice” message having the updated connection request tables to the terminals  101  and  102 . When the terminal  101  receives the “connection table updating notice” message, the terminal  101  changes the screen into a screen as shown in  FIG. 23 . Recording is performed while the screen in  FIG. 23  is displayed. 
   The exchange apparatus which handles voices and holding sounds has been described in the above embodiment. However, the present invention may be applied to an exchange apparatus which handles still images, moving images, or pieces of music in place of the above exchange apparatus. In this case, data flowing between a terminal or the exchange apparatus and a terminal are not voice data, but are data of still images, moving images, or pieces of music. 
   In the embodiment described above, although only a connection state related to a self-terminal is displayed on the screen of the self-terminal, the connection states of all the terminals managed by the exchange apparatus  111  may be displayed. In this case, on the screen of the exchange apparatus  111 , sets of icons  405  to  407  are displayed to the number of terminals managed by the exchange apparatus. 
   In addition, a certain terminal may be used as a management terminal, and not only “connection table updating notice” messages related to the management terminal but also “connection table updating notice” messages related to terminals different from the management terminal may be transmitted to the management terminal, and the same screen as that of the exchange apparatus may be displayed on the management terminal. 
   The same screen as that of the exchange apparatus may be arranged on each terminal, so that a user can recognize whether a destination terminal is busy or not before calling the destination terminal. 
   In the embodiment, the “connection table updating notice” messages are transmitted to respective terminals. However, the contents of the “connection table updating notice” messages simultaneously transmitted to different terminals are equal to each other. If a group of a terminal which receives the “connection table updating notice” message is set in advance, then one “connection table updating notice” message is flowed into the extension line L 21 , and only terminals belonging to the group may read the message. Furthermore, when users listen to the same melody through a plurality of terminals, only one melody may be flowed into the extension line L 21  to cause the plurality of terminals to pick up the melody. For this reason, the delay due to congestion of lines caused by flowing the same messages, the same voices, or the same pieces of music on the extension line L 21  is prevented. In addition, the delay of data preparation due to overload for the exchange apparatus to generate the same messages, the same voices, and the same pieces of music can be prevented. 
   In the above embodiment, although drag and drop performed by a mouse are used as an operation method, any operation method which designates a source icon to be dragged and a destination icon on which the source icon is to be dropped may be used. For example, an operation method in which the source icon and an the destination icon are clicked by a mouse is used, or a touch panel may be used in place of the mouse. 
   In the above embodiment, an effect obtained when the first icon is dragged and dropped to the second icon may be obtained when the second icon is dragged and dropped to the first icon. 
   In the above embodiment, only the three icons, i.e., the icon  407  representing the self-terminal and the icons  405  and  406  representing the destination terminals in a telephone call are displayed. In this display, only a connection state among a maximum of three persons can displayed. However, when icons representing destination terminals in a telephone call are increased in number, a connection state among four or more persons can also be displayed. The numbers of destinations, call originating terminals, recording terminals, and holding terminals for holding sound may be increased depending on the specifications of exchange apparatuses. 
   In the above embodiment, although only the single icon  411  is used as an icon representing a holding sound source, a plurality of icons representing holding sound sources may be displayed. In this case, sets of icons  411 ,  412 , and  413  may be arranged in respective windows. In this connection, the different sets may use holding sounds having different melodies, respectively. In order to realize this, a plurality of melody files should be stored in the storage device  110 , and the melody files to be reproduced are changed depending on the selected set. In addition, melody files may be changed by uploading a melody file from a terminal. In this case, a pop-up menu for uploading a file is displayed by an operation performed by right-clicking the icon  411  representing the holding sound source by the mouse to make it possible to select one of melody files held by a terminal, and the selected file may be transmitted from the storage device  211  of the terminal to the storage device  110  of the exchange apparatus. 
   In the above embodiment, connection between the self-terminal and the holding sound source is not described. However, the exchange apparatus may have the following function. That is, for example, the self-terminal and the holding sound source are connected to each other by dragging and dropping the icon  411  representing the holding sound source to the icon  407  representing the self-terminal, so that a user easily listens a holding melody through the self-terminal. 
   In the above embodiment, a telephone conference call is not described. However, for example, when the icon  401  representing a registered destination is dragged and dropped to the icon  405  representing a destination terminal, and the icon  402  representing another registered destinations is dragged and dropped to the icon  406  representing another destination terminal, so that a telephone conference is enabled. 
   In the above embodiment, only cases in which a connection request of the terminal  101  is accepted by any other terminals is described. However, a connection request accepted by the terminals may be restricted. In this case, connection authorities for the terminals are set to the storage device  110  of the exchange apparatus  111  in advance. When the exchange apparatus  111  receives a “connection request” message, the exchange apparatus  111  decides whether a destination will accept the connection request from the source or not with reference to the storage device  101 . If the destination refuses the “connection request”, the exchange apparatus  111  transmits a “request rejection” message to the source which has transmitted the “connection request” message without performing a connection process. 
   In the above embodiment, a function of listening to the contents of voice message through a self-terminal in real time while a partner terminal which originated a call records the voice message on an answerphone recording device is not described. However, this function can be realized by any one of the following two methods. The first method is as follows. When the icons  408 ,  409 , or  410  representing the terminal calling the self-terminal is dragged and dropped to the icon  405  representing a destination terminal, and when the icon  414  or  416  representing a recording device is dragged and dropped to the icon  406  representing another destination terminal, the calling terminal and the self-terminal are connected to each other in a direction from the calling terminal and the self-terminal, and the self-terminal and the recording device are connected to each other in a direction from the self-terminal to the recording device. The second method is as follows. When the icons  408 ,  409 , or  410  representing the terminal calling the self-terminal is dragged and dropped to the icon  405  representing a destination terminal, and when the icon  414  or  416  representing a recording device is dragged and dropped to the icon  405  representing another destination terminal, the calling terminal and the self-terminal are connected to each other in a direction from the calling terminal and the self-terminal, and the self-terminal and the recording device are connected to each other in a direction from the self-terminal to the recording device. 
   According to the present invention, a change in connection and the like can be executed by an integrated and intuitive operation, the trouble of learning operation methods by reading manuals for respective functions can be eliminated, and erroneous operations can be prevented. 
   According to the present invention, all the connections and incoming states for a self-terminal are visually displayed to make it possible that a user recognizes the connections and incoming states state at a glance and to make it easier to perform an operation of responding to important incoming with priority. In addition, when connection states of other terminals are displayed on a screen, it can be recognized whether a destination terminal is busy or not before an outgoing operation is performed, and useless outgoing operations can be reduced. 
   According to the present invention, since even a “connection change request” is sent for connection which is not related to a self-terminal to make it possible to change the connection, and a “connection table updating notice” can be sent to any terminal from an exchange apparatus with respect to a connection state, even an unrelated terminal can recognize connection states of other apparatuses. Thus, an entire connection state can be recognized by a management terminal and the like, and hindrance or illegal use of terminals can be early detected.