Abstract:
An IP telephone system having a plurality of terminals, comprising storage means storing relationships between terminal ID and user ID for each of the plurality of terminals, server performing call processing control related to each terminal logged in and registered, storage means storing upper limit numbers of the respective terminals possible to log in for each user in accordance with the user ID, comparison means comparing and collating between the number of the logged in and registered terminals and the upper limit number corresponding to the user ID on the basis of the user ID, when the user ID is input in the terminal, and controller allowing terminal with the user ID input thereto to be logged in and registered, when the number of the logged in and registered terminal is not more than the upper limit number as the result of comparison and collation from the comparison means.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2004-372858, filed Dec. 24, 2004, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an Internet protocol (IP) telephone system for make a communication via an IP network (for example, the Internet).  
         [0004]     2. Description of the Related Art  
         [0005]     An Internet telephone (hereinafter, referred to as IP telephone) to make a communication via the IP network has been known. The IP telephone system has an server to perform communication control among IP telephone terminals. Additional providing of a registrar server to manage user IDs and the IP telephone terminals causes a possibility of communications by using the same user ID from any where through the IP telephone terminals connected to the IP network.  
         [0006]     In the system performing such communication control, the burden of a server to manage IP addresses and the user IDs of the IP telephone terminals becomes heavy with the increase of the number of the IP telephone terminals. Since an IP address resource is finite, a method for effectively utilizing an address resource by converting a global address into a local address has been introduced [for example, refer to Jpn. Pat. Appln. KOKAI publication No. 11-122285 (page fourteenth, FIG. 1)].  
         [0007]     Although this method is effective to save the IP address resource, this method cannot realize an ID management function to manage a large number of IP telephone terminals by using the same user ID. Accordingly, in the case of a large number of IP telephone terminals, the processing load related to the server to manage the IP addresses and the user IDs of the IP telephone terminals are still large.  
         [0008]     The IP telephone system makes it possible for IP telephone terminals to make telephone calls from any where through an IP network by using the same user ID. However, this system has the problem such that a load of the server becomes large with an increase of the number of IP telephone terminals.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     According to an aspect of the present invention, there is provided an IP telephone system having a plurality of telephone terminals, comprising: identification number storage means for storing relationships between telephone terminal identification numbers and user identification numbers for each of the plurality of telephone terminals; server means for performing call processing control related to each telephone terminal which is logged in and registered; upper limit number storage means for storing upper limit numbers of the respective telephone terminals possible to log in for each user in accordance with the user identification numbers; comparison and collation means for comparing and collating between the number of the logged in and registered telephone terminals and the upper limit number corresponding to the user identification number on the basis of the user identification number, when the user identification number is input in the telephone terminal; and log-in control means for allowing the telephone terminal with the user identification number input thereto to be logged in and registered, when the number of the logged in and registered telephone terminal is not more than the upper limit number as the result of comparison and collation from the comparison and collation means.  
         [0010]     Additional advantages of the invention will be set forth in the description on which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0011]     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.  
         [0012]      FIG. 1  is an exemplary block diagram showing an IP telephone system regarding an embodiment of the present invention;  
         [0013]      FIG. 2  is an exemplary flowchart showing an operation procedure of an IP telephone terminal in the IP telephone system regarding the embodiment of the present invention;  
         [0014]      FIG. 3  is an exemplary view showing a table with an upper limit number of IP telephone terminals capable of being simultaneously log in by each user registered therein;  
         [0015]      FIGS. 4A  to  4 D are exemplary views showing a registration list indicating correspondence between each IP telephone terminal and user ID;  
         [0016]      FIG. 5  is an exemplary block diagram of an IP telephone system regarding a second embodiment of the present invention;  
         [0017]      FIG. 6  is an exemplary block diagram of an IP telephone system regarding a third embodiment of the present invention; and  
         [0018]      FIG. 7  is an exemplary block diagram of an IP telephone system regarding a fourth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     Hereinafter, embodiments of the present invention will be explained by referring to the drawings.  
         [0020]      FIG. 1  is an entire view of an IP telephone system regarding an embodiment of the present invention.  
         [0021]     In  FIG. 1 , the IP telephone system comprises a plurality of IP telephone terminals  1  ( 1 A- 1 M), an SIP server  2 , a configuration information management server  3  and an IP network  4  which connects each of the constituent elements given above.  
         [0022]     The IP telephone system regarding the embodiment sets the upper limit number of the IP telephone terminals  1  allowed to simultaneously log in the IP telephone system for each user. This upper limit number is associated with each user to be stored in the configuration information management server  3 . The IP telephone terminal  1  downloads the upper limit number for a user from the management server  3  and downloads the number of IP telephone terminals which have already logged in, from a registrar server  21  of the SIP server  2  to collate and compare between the two numbers in accordance with a log-in operation by the user. If the number of the IP telephone terminals which have already logged in reaches the upper limit number, the user who has performed the log-in operation is not allowed to log in the IP telephone system. Therefore, the IP telephone system can reduce IP address management, user ID management and call connection processing and prevent the load on the SIP server  2  from being increased.  
         [0023]     Any user of the IP telephone system obtains each proper identification number (hereinafter, referred to as user ID) “U1”-“Un”. When a user make a telephone call by means of an IP telephone terminal  1  (for example, IP telephone terminal  1 A), a user ID is input to an IP telephone terminal  1 A.  
         [0024]     It is assumed that three sets of IP telephone terminals  1 A- 1 C are used by the users with user ID of “U1”. The IP telephone terminal  1 A is installed in an office. An IP telephone terminal  1 B is a wireless LAN terminal to be connected to the IP network  4  through an access point  5 . An IP telephone terminal  1 C is installed in a conference room. The user with a user ID of “Un” uses an IP telephone terminal  1 M.  
         [0025]     The SIP server  2  has a registrar server  21 . The registrar server  21  has a registration list  211  therein. The registration list  211  registers information in which identification information of the IP telephone terminals  1 A- 1 M and the user IDs “U1”-“Un” of the user who use the IP telephone terminals  1 A- 1 M are made in pairs, respectively. The SIP server  2  also includes a call connection management unit  22  to control call connection of the IP telephone terminals which have logged in to the IP telephone system.  
         [0026]     The configuration information management server  3  stores a table  31  to manage the upper limit number of the IP telephone terminals  1 A- 1 M to which each user can simultaneously log in. The SIP procedure of the embodiment automatically performs log-in processing to the IP telephone system when the registrar server  21  receives registration information of terminal users from the IP telephone terminals  1  to store it in the registration list  211 . The Sip server  2  does not perform log-in control to the IP telephone terminals  1 .  
         [0027]      FIG. 2  is the exemplary flowchart showing the operation procedures in the IP telephone system in  FIG. 1 . Operations and processing procedures in the IP telephone system will be described in parts of (1) log-in processing up to the upper limit number, (2) compulsory log-in processing, and (3) re-log-in processing (continuation of log-in, and log-out).  
         [0028]     (1) Log-In Processing Up to the Upper Limit Number  
         [0029]     It is assumed that the IP telephone terminal  1 A and the IP telephone terminal  1 M are tuned on under a condition in which the user IDs and the IP addresses of the IP telephone terminals  1  are not registered in the registrar server  21  (step s 101 ). Both IP telephone terminals  1 A and  1 M acquire own IP addresses, IP address of the SIP server  2  and IP address of the configuration management information server  3  in accordance with a dynamic host configuration protocol (DHCP) procedure (step s 102 ).  
         [0030]     Next, the user ID “U1” is input to the IP telephone terminal  1 A (step s 103 ). This user ID is input in accordance with a prescribed procedure through key buttons or the like of the IP telephone terminals  1 . If the IP telephone terminals are ones to which personal computers or the like are used, the user IDs may be input through the keyboards of the computers or the like.  
         [0031]     The IP telephone terminal  1 A accesses to the IP network  4  and downloads configuration information, showing the upper limit number “2” of the IP telephone terminals  1  having the user IDs “U1” and possible to be simultaneously registered, from the configuration management information server  3  to read out it (step s 104 ). The input of the user ID “Un” to the IP telephone terminal  1 M results in downloading of “3” to the IP telephone terminal  1 M in a procedure similar to one given above.  
         [0032]      FIG. 3  is an exemplary view showing a table  31  stored in an internal memory of the configuration management information server  3 . In  FIG. 3 , the upper limit numbers of the IP telephone terminals  1  possible to simultaneously log in are initially preset for each user “U1”-“Un” who have registered into the management server  3 , as the users of the IP telephone system. Two sets for the User “U1” and three sets for the user “Un” are stored as the respective upper lime numbers in the table  31 . This initial setting is executed by an administrator through, for example, a management terminal (not shown) connected to the management server  3  or the IP network  4 . The initial setting gives the upper limit number of the IP telephone terminals, possible to log in for each user “U1”-“Un”, to the IP telephone system.  
         [0033]     Next to this, each IP telephone terminal  1 A and  1 M downloads the registration list  211  with the input user ID (for example “U1” for telephone terminal  1 A) and its user “U1” registered therein from the registrar server  21  to read out the already registered number “0” of the user “U1” (step s 105 ). In this case, the number of the IP telephone terminals  1  is one by collating and comparing the number of the IP telephone terminals  1  to the upper limit number “2” of the user “U1”, which has been read out by downloading the table  31  from the management server  3 , and the number “1” is not more than the upper limit number possible to log in, so that the IP telephone system determines that the telephone terminal may log in thereto (No, in steps s 107  and s 108 ). Then the IP telephone system transmits data of a suite of the IP address and the user ID of its own IP telephone terminal  1 A to the registrar server  21  to register it (step s 109 ).  
         [0034]     Registrar server  21  receives this registration information to write, store and register it in the registration list  211  then the IP telephone terminal  1 A is logged in the IP telephone system. The SIP server  2  then constantly monitors the registration list  211  of the registrar server  21  to perform call connection control between the registered IP telephone terminals  1 .  
         [0035]     That is to say, each IP telephone terminal  1 A, if furthermore a telephone number of a call arrival destination is input by the user “U1” after logging in the IP telephone system, transmits the telephone number to the SIP server  2  to request call connection (step s 110 ). The call connection control unit  22  of the SIP server  2  receives the call request then performs the call connection control between the IP telephone terminal  1  having the telephone number of the call arrival destination. These procedures up to the call connection processing go the same for the IP telephone terminal  1 M.  
         [0036]      FIG. 4  shows the registration list  211  showing combinations of each IP telephone terminal  1  and user IDs stored in the internal memory of the registrar server  21 . The (a) of FIG. A shows a state immediately after the IP telephone terminals  1 A and  1 M are registered for the first time. The IP telephone terminal  1 A is registered for a user who has a terminal ID “1A”, a terminal IP address “192.168.100.1” and a user ID “U1” and described as an address U1@192.168.100.1 that makes a pair with the user ID “U1”. And an IP telephone terminal  1 M is registered for a user who has a terminal ID “1M”, an IP address “192.168.100.3” and a user ID ‘Un’ and described as “Un@192.168.100.3”. The IP address indicating the association to bring the user and the IP telephone terminal into a pair may be either a global address or a local address.  
         [0037]     Next to this, it is assumed that the user turns on an IP telephone terminal  1 B that is the wireless LAN terminal. The IP telephone terminal  1 B operates the same operations as those of the aforementioned IP telephone terminal  1 A, then downloads the registration list  211  from the registrar server  21  and conducts the operations up to step s 106  in  FIG. 2  in which the number of the already registered sets of the IP telephone terminals having the User ID “U1” is collated and compared to the upper limit number of sets possible to be registered. When reading out the registration list  211 , it is determined that one set has already been registered for the user “U1” and log-in should be allowed because the total number of sets becomes two and settles not more than the upper limit number “2” even after registration of its own terminal and conducts processing after step s 109  as similar to the processing of previous time. The (b) of  FIG. 4  is the registration list  211  when the user “U1” is registered in the IP telephone terminal  1 B. The IP telephone terminal  1 B is registered in the user with a terminal ID “1B”, an IP address “192.168.200.5” and a user ID “U1” and described as “U1@192.168.200.5”.  
         [0038]     (2) Compulsory Log-In Processing  
         [0039]     Compulsory log-in is performed at the time when a user wants to further log in the IP telephone system in which other users have already logged in through the IP telephone terminals as many as the upper limit number. The IP telephone terminal  1  of the user who has forcibly logged in is treated to be logged out by timer processing so as to be settled within the upper limit number, as below-mentioned description (3) about re-log-in.  
         [0040]     Furthermore, operations of an IP telephone terminal  1 C in the case that the user “U1” further moves to a conference room from an office and tries to make a telephone call from the IP telephone terminal  1 C placed in the conference room then enters a waiting state for the compulsory log-in will be described.  
         [0041]     The user “U1” inputs the user ID “U1” to the IP telephone terminal  1 C so as to make the IP telephone terminal  1 C log in before making a telephone call (step s 103 ). The IP telephone terminal  1 C then downloads the maximum upper limit number “2” of the IP telephone terminals respectively having the user IDs “U1” from the management server  3  and a current registration list  211  shown in the (b) of  FIG. 4  from the registrar server  21  (steps s 104  and s 105 ). And the IP telephone terminal  1 C collates and compares between the pre-registered number of the IP telephone terminals  1  in relation to the user ID “U1” and the upper limit number (step s 106 ). The IP telephone terminal  1 C then reads the registration  211  to determine that more registration is not allowed and the user should wait for an input for the compulsory log-in, because the number of the IP telephone terminal  1 C results in the third one and exceeds the upper limit number (Yes, in step s 107 ) and the IP telephone terminal  1 C (namely, own telephone terminal) has not registered in the registration list  211  (step s 113 ).  
         [0042]     After this, the IP telephone terminal  1 C notifies an alarm of impossibility of log-in to the user “U1” by some means. Here, means for displaying a lamp (not shown) attached to the IP telephone terminal  1 C (for example, lighting off a display for communicability, or lighting on alarm for incommunicability), for not outputting a tone signal from a telephone receiver, or for outputting an alarm for impossibility of log-in is used.  
         [0043]     The user “U1” who has come to know the alarm determines that ordinal registration (log-in) is impossible. The user “U1” then tries to input a compulsory log-in command through a prescribed key button operation (Yes, in step s 114 ). At this time, the IP telephone terminal  1 C transmits registration information about a combination of the IP address “192.168.100.2” and the user ID “U1” to the registrar server  21  (step s 109 ) to perform the compulsory log-in to the IP telephone system and further transmits a telephone number, which has been input by the user “U1”, to the SIP server  3  to make a telephone call (step s 110 ).  
         [0044]     The (c) of  FIG. 4  is an exemplary view showing the registration list  211  of the registrar server  21  immediately after the implementation of the compulsory log-in. In the (c) of  FIG. 4 , the user “U1” should be registered two sets at a maximum fundamentally; however the compulsory log-in has been performed, so that total three sets of the IP telephone terminals  1  have been registered in the registration list  211  exceptionally.  
         [0045]     On the contrary, it is assumed that the user suspends to make a telephone call from the IP telephone terminal  1 C because of the impossibility of log-in of the user “U1” (No, in step s 114 ). In this case, the IP telephone terminal  1 C holds steady to wait for the input of the command of the compulsory log-in and does not conduct a log-in operation.  
         [0046]     (3) Re-Log-In Processing (Continuation of Log-In, and Log-Out)  
         [0047]     In SIP procedures, the registrar server  21  automatically deletes each IP telephone terminal  1  of which the time progress reaches a prescribed period, respectively (for example, thirty minutes) from the registration list  211 . The IP telephone terminals  1  which have been logged in are logged out. Accordingly, each IP telephone terminal  1  therefore executes procedures to re-log in (re-register) to avoid log-out and allow them to be continuously used (step s 111 ).  
         [0048]     Two methods are provided for the re-log-in processing. A first method automatically conducts the re-log-in processing before a prescribed period (for example, thirty minutes) is elapsed (for example, fifteen minutes that is a half of the prescribed period) after the log-in. A second method respectively inputs the re-log-in commands to the IP telephone terminals  1 .  
         [0049]     (First Method)  
         [0050]     In the first method, depending on the same manner in the conventional SIP procedures, each IP telephone terminal  1  automatically conducts the re-log-in processing at a time point when a half time of the prescribed period (for example, fifteen minutes) elapses by referring to a timer (not shown) after logging in. Now, it is assumed that a time period (for example, thirty minutes after the last log-in), in which the user “U1” requires to re-log-in (re-register) by means of the IP telephone terminal  1 A in the office while the user “U1” is in meeting in the conference room, has elapsed.  
         [0051]     Being in the conference room, the user “U1” cannot perform the re-log-in operation for the IP telephone terminal  1 A; however the IP telephone terminal  1 A automatically re-logs in before the fifteen minuets elapses (step s 115 ).  
         [0052]     That is, the IP telephone terminal  1 A, of which the timing for the re-log-in has reached, inputs for the re-log-in (Yes, in step s 115 ) to download the registration list  211  from the registrar server  21  (step s 105 ) and compares to the upper limit number of the user “U1” (step s 106 ).  
         [0053]     If the number of the IP telephone terminals  1  by which the user “U1” are now logging in is less than the upper limit number allowed to be registered (No, in steps s 107  and s 108  in  FIG. 2 ), the user “U1” transmits the IP address and the user ID of its own terminal to the registrar server  21  to overwrite-register them and logs in again.  
         [0054]     It is assumed that the number of the IP telephone terminals by which the user “U1” are now logging in reaches the upper limit number allowed to be registered (Yes, in step s 107  in  FIG. 2 ). In this state, since the registered terminal number is equal to the upper limit number resulting from automatic re-log-in to check the already-registered terminal number and its own terminal has already registered in the registration list  211  (Yes, in step s 112 ), the user “U1” transmits the IP address and the user ID “U1” of its own terminal to the registrar server  21  to register them for the re-log-in (step s 109 ) and terminates the re-log-in processing. In the aforementioned two examples, the user “U1” can make a telephone call from the IP telephone terminal  1 A without having to conduct the log-in processing when returning to the office.  
         [0055]     In contrast, if the number of the IP telephone terminals  1  by which the user “U1” is now logging in exceeds the upper limit number allowed to be registered (Yes, in steps s 107  and s 108 ), the IP telephone terminal  1 A is brought into a compulsory log-in waiting state. Since the user “U1” is in the conference room, an operation for the compulsory log-in is not conducted from the IP telephone terminal  1 A in the office (No, in step s 114 ). The IP telephone terminal  1 A then expires and automatically logs out.  
         [0056]     Similarly, the registrar server  21  watches the elapsed time period after receiving the registration information of the IP telephone terminal  1 A by the internal timer. After the elapse of the prescribed period (thirty minutes) after the last log-in success of the IP telephone terminal  1 A, the IP telephone terminal  1 A is deleted from the registration list  211 .  
         [0057]     As mentioned above, if the number of the IP telephone terminals  1  registered in the registration list  211  is not more than the upper limit number of the user “U1”, the IP telephone terminals  1  which have logged in once are not deleted from the registration list  211  and retain the log-in states successively as long as commands for log-out are not input respectively by the user “U1”.  
         [0058]     The first method is convenient because the IP telephone terminals  1  are not logged out and do not need procedures to perform re-log-in processing as long as the number of the IP telephone terminals  1  being in log-in is not more than the upper limit number.  
         [0059]     (Second Method)  
         [0060]     In the second method, the user inputs the re-log-in command to the IP telephone terminals  1  within the prescribed time period (wherein, thirty minutes) in which the registrar server  21  updates the registration list  211 .  
         [0061]     Now, it is assumed that the user “U1” makes a radio communication through an IP telephone terminal  1 B that is a wireless LAN terminal and makes a telephone call at an appropriate time by using the IP telephone terminal  1 A. However, when the time, immediately before (for example, one minute) the elapse of thirty minutes after the first log-in without making any telephone call by using the IP telephone terminal  1 A, comes, the IP telephone terminal  1 A displays an alarm to prompt the re-log-in (re-registration) by a lamp in accordance with the internal timer. The user “U1” recognizes the alarm by the lamp to perform the re-log-in and, for example, the user presses the key button in accordance with prescribed procedures so as to input the re-log-in command (Yes, in step s 115 ). (As a matter of course, the IP telephone terminal  1  may automatically log out without output the alarm to prompt the re-registration as described above after the lapse of the re-registration time.)  
         [0062]     The IP telephone terminal  1 A with the re-log-in command input thereto downloads the registration  211  from the registrar server  21  in accordance with the procedures in step s 105 . When the IP telephone terminals  1 A reads the registration list  211 , the user “U1” determines that the IP telephone terminal  1 B has also been registered and the IP telephone terminal  1 A intends to be re-registered in a state of the upper limit number “2” of the user “U1” (Yes, in step s  107 ).  
         [0063]     Then, the IP telephone terminal  1 A further collates whether or not the IP address of its own terminal is present in the registration list  211  to read the description of U1@192.168.100.1 and determines that it is possible to register the IP telephone terminal  1 A if its own IP address is present in the registration list  211  (Yes, in step s 112 ). The IP telephone terminal  1 A executes a procedure of the re-log-in processing to transmit the registration information of the ID of the user “U1” and the IP address of the IP telephone terminal  1 A (step s 109 ).  
         [0064]     As another case, it is assumed that a time period (for example, thirty minutes), which is required for the IP telephone terminal  1 A in the office to re-log in (re-register), elapses while the user “U1” is in a meeting in the conference room. Since the user “U1” is in the conference room, even when the registered number in relation to the compulsory log-in operations or the user “U1” does not reach the upper limit, the command operation for the re-log-in is not conducted (No, in step s 115 ), so that the IP telephone terminal  1 A expires and automatically logs out.  
         [0065]     Likewise, the registrar server  21  watches the elapsed time period after receiving the registration information of the IP telephone terminals  1  by the internal timer. Then, after the elapse of the prescribed time period (thirty minutes) after the last log-in success of the IP telephone terminal  1 A, the IP telephone terminal  1 A is deleted from the registration list  211 .  
         [0066]     The second method is effective in the case that an allowable amount limit of terminals in the IP telephone system is strict, because the corresponding IP telephone terminal is automatically logged out and deleted from the registration list  211 , even if the number of the IP telephone terminals during connection is not reaches the upper limit number as long as the re-log-in command is not input.  
         [0067]     The (d) of  FIG. 4  shows the registration list  211  of the registrar server  21  in a state that the IP telephone terminals  1 A and  1 B log out and only the IP telephone terminal  1 C logs in after the compulsory log-in is performed.  
         [0068]     The IP telephone terminal  1  which has become in a state waiting for the compulsory log-in may read out the registration list  211  of the registrar server  21  at a fixed time interval to detect the fact that the IP telephone terminals  1  become possible to log in.  
         [0069]     For example, in the (c) of  FIG. 4 , while the IP telephone terminal  1 M by which the user “U1” intends to make a telephone call at a moving destination executing the procedure of waiting for an input of the compulsory log-in (step s 113 ), the IP telephone terminal  1 M automatically downloads the registration list  211  from the registrar server  21  periodically, for example, with every several minute interval (step s 105 ). The IP telephone terminal  1 M then determines that the number of the IP telephone terminals to log in becomes not more than the upper limit number (here, assumed as two) even if the IP telephone terminal  1 M itself is logged in by detecting the log-out of the IP telephone terminals  1 A and  1 B when the IP telephone terminal  1 M is brought into a state of the (d) of  FIG. 4 . The IP telephone system can prompt the user “U1” to input the user ID and the telephone number to make a telephone call by indicating the fact that the IP telephone terminal  1 M is in the state of possibility of log-in thereto by means of a lamp or the like. The IP telephone terminal  1 C may automatically transmit the registration information and log in in stead of the log-in operation by the user “U1” when the IP telephone terminal  1 C determines to be able to log in during waiting for the compulsory log-in.  
         [0070]     Although the IP telephone system of the embodiment in the present invention is configured to comprise a configuration information management server  3  independently in  FIG. 1 , each of the servers may be configured to be independent with one another, or configured to be in a combination thereof or to be built in other server, other than the configuration shown in  FIG. 1 .  
         [0071]      FIG. 5  is, for example, an exemplary block diagram showing a second embodiment of the invention in which the SIP server  3 , registrar server  21  and configuration information management server  3  are independently configured to be connected to the IP network  4 .  FIG. 6  is an exemplary block diagram showing a third embodiment of the invention in which the registrar server  21  and configuration information management server  3  are built in the SIP server  2  and inner buses connect each server. Furthermore,  FIG. 7  is an exemplary block diagram showing a fourth embodiment of the invention that is an apparatus in which a server  20  incorporates the IP server  2 , registrar server  21  and configuration information management server  3  are incorporated, or that is a system configuration. In this case, each server is connected through either the IP network  4  or the inner buses. Even in the second to fourth embodiments of the invention, the operation procedures or the like in the IP telephone system, namely, among the IP telephone terminals and each server are similar to those of the first embodiment.  
         [0072]     As given description, the IP telephone system of the present invention sets the upper limit number of the IP telephone terminals and makes the SIP telephone terminal itself control whether its log-in is allowed or not. Thereby, the situation, in which the user can make a telephone call from any IP telephone terminal without any limitation, is prevented. Consequently, the IP telephone system can suppress a load increase in IP address management, user ID management and call connection processing.  
         [0073]     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.