Abstract:
A network telephone system includes a plurality of telephone terminals located in specific countries and districts respectively, a network which connects the telephone terminals and transmits a plurality of voice packets, and a main apparatus connected to the network, and makes an exchange between the telephone terminals, the telephone terminals each includes, a selector which selects at least one of the countries and districts, and an informing circuit to inform selection signal to the main apparatus together with identification information of self telephone terminal, the main apparatus includes a memory which stores information indicating the countries and districts correspondingly to the identification information, a reader which reads the information corresponding to identification information arrived from the telephone terminal via the network from the memory, and a provider which provides services in according to read result and the selection signal to telephone terminal making a call.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2003-400898, filed Nov. 28, 2003, 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 a network telephone system, which connects IP (Internet Protocol) telephone terminals located in various countries and districts via a packet communication network. In addition, the present invention relates to the main apparatus and telephone terminal of the network telephone system.  
         [0004]     2. Description of the Related Art  
         [0005]     In recent years, a network telephone system (IP telephone system) has come into wise use. According to the network telephone system, image and voice are bi-directional transmitted and received as packet data via a packet communication network in real time. According to the IP telephone system, voice communications are made between IP telephone terminals connected to the packet network. Of course, the voice communications are also made between telephone terminals connected to the IP telephone terminals and public network. In addition, the voice communications are made between various countries and districts via the packet communication network.  
         [0006]     In the IP telephone system, time information preset in the main apparatus has been displayed on the display of the IP telephone terminal. However, according to the remote station form, time difference is generated between the IP telephone terminal and the main apparatus. For this reason, time indication suitable to each country and district is required.  
         [0007]     In view of the foregoing circumstances, the following method has been proposed (e.g., JPN. PAT. APPLN. KOKAI Publications No. 2002-84371 and 2002-94702). According to the method, the time difference is offset between IP telephone terminals making a call through country or district to meet time information of the other end of the line.  
         [0008]     However, the foregoing method has the problem described below. More specifically, time information of the other end making the call is displayed on the caller side only for the period when a call is being made through country or district. On the other hand, time information of the country or district of the caller is only displayed in the time other than the foregoing period. For example, a businessman from America temporarily stays in Japan, and he made a call to America using the IP telephone terminal in Japan. In this case, American standard time is not obtained until a calling state is given; for this reason, this is very inconvenient to the businessman from America.  
         [0009]     If an emergency call is made from the IP telephone terminal located in the country different from the main apparatus, the call is interpreted as the emergency number on the country of the main apparatus; as a result, a troublesome problem happens.  
       BRIEF SUMMARY OF THE INVENTION  
       [0010]     It is, therefore, an object of the present invention to provide a network telephone system, which is capable of using services suitable to various countries or districts. Another object of the present invention is to provide the main apparatus and telephone terminal of the network telephone system.  
         [0011]     According to an aspect of the present invention, there is provided a network telephone system comprising: a plurality of telephone terminals located in specific countries and districts respectively; a network which connects the telephone terminals and transmits a plurality of voice packets; and a main apparatus connected to the network, and makes an exchange between the telephone terminals, the telephone terminals each including: a selector which selects at least one of the countries and districts, to generate a selection signal; and an informing circuit to inform the selection signal to the main apparatus together with identification information of self telephone terminal; the main apparatus including: a memory which stores information indicating the countries and districts correspondingly to the identification information; a reader which reads the information corresponding to identification information arrived from the telephone terminal via the network from the memory, to generate a read result; and a provider which provides services in according to the read result and the selection signal to telephone terminal making a call.  
         [0012]     According to another aspect of the present invention, there is provided a main apparatus used for a network telephone system comprising: a plurality of telephone terminals located in specific countries and districts respectively; a network connecting the telephone terminals and transmitting a plurality of voice packets; and a main apparatus connected to the network, and making an exchange between the telephone terminals, the main apparatus comprising: a memory which stores information indicating the countries and districts correspondingly to identification information indicating one of the telephone terminals; a reader which reads the information corresponding to the identification information arrived from one of the telephone terminals from the memory, to generate a read result, when the telephone terminal generates the identification information and a selection signal by selecting at least one of the countries and districts; and a provider which provides services in according to the read result and the selection signal to telephone terminal making a call.  
         [0013]     According to yet another aspect of the present invention, there is provided a telephone terminal used for a network telephone system comprising: a plurality of telephone terminals located in specific countries and districts respectively; a network connecting the telephone terminals and transmitting a plurality of voice packets; and a main apparatus connected to the network, and making an exchange between the telephone terminals, the telephone terminal comprising: a selector which selects at least one of the countries and districts, to generate a selection signal; and an informing circuit to inform the selection signal to the main apparatus together with identification information of self telephone terminal.  
         [0014]     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and 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  
       [0015]     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred 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.  
         [0016]      FIG. 1  is a schematic view showing the configuration of an IP telephone system according to a first embodiment of the present invention;  
         [0017]      FIG. 2  is a block diagram showing the functional configuration of an IP telephone main apparatus shown in  FIG. 1 ;  
         [0018]      FIG. 3  is a view showing storage contents of a country-district classification table in  FIG. 2 ;  
         [0019]      FIG. 4  is a view showing storage contents of an IP telephone terminal/country-district corresponding table shown in  FIG. 2 ;  
         [0020]      FIG. 5  is a view showing storage contents of a gateway/country-district corresponding table shown in  FIG. 2 ;  
         [0021]      FIG. 6  is a block diagram showing the functional configuration of an IP telephone terminal shown in  FIG. 1 ;  
         [0022]      FIG. 7  is a flowchart to explain the operation by the IP telephone main apparatus when updating time in the first embodiment;  
         [0023]      FIG. 8  is a view to explain the connection operation in each call path in the first embodiment;  
         [0024]      FIG. 9  is a flowchart to explain the operation by the IP telephone main apparatus when making a local call following an automatic path select code using an IP telephone terminal in the first embodiment;  
         [0025]      FIG. 10  is a flowchart to explain the operation by the IP telephone main apparatus when making a long-distance call following an automatic path select code using the IP telephone terminal in the first embodiment;  
         [0026]      FIG. 11  is a flowchart to explain the operation by the IP telephone main apparatus when making an international call following an automatic path select code using the IP telephone terminal in the first embodiment;  
         [0027]      FIG. 12  is a flowchart to explain the operation by the IP telephone main apparatus when making an emergency call using an IP telephone terminal time in the first embodiment;  
         [0028]      FIG. 13  is a schematic view showing the configuration of an IP telephone system according to a second embodiment of the present invention;  
         [0029]      FIG. 14  is a block diagram showing the functional configuration of an IP telephone main apparatus shown in  FIG. 13 ;  
         [0030]      FIG. 15  is a schematic view showing the configuration of an IP telephone system according to a third embodiment of the present invention;  
         [0031]      FIG. 16  is a table showing the corresponding relationship between node identifiers for identifying a USA node and countries and districts of GW used for making a call in gateways belonging to the USA node; and  
         [0032]      FIG. 17  is a flowchart to explain the operation by the IP telephone main apparatus when a node identifier dials up using an IP telephone terminal. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     Embodiments of the present invention will be described below with reference to the accompanying drawings.  
       FIRST EMBODIMENT  
       [0034]      FIG. 1  is a schematic view showing the configuration of an IP telephone system according to a first embodiment of the present invention.  
         [0035]     According to the IP telephone system, IP telephone terminal IPT 1  and gateway GW 1 , IPT 2  and GW 2 , IPT 3  and GW 3  are located in a country A, the West of a country A and the East thereof, respectively. In addition, a main apparatus BT is located in the East of the country B. The IP telephone terminals IPT 1  to IPT 3  and gateways GW 1  to GW 3  are connected to the main apparatus BT via an IP network IPN.  
         [0036]     The gateway GW 1  is connected a public network INW 1  and a known telephone terminal GWT 1 . The gateway GW 2  is connected a public network INW 2  and a known telephone terminal GWT 2 . The gateway GW 3  is connected a public network INW 2  and a known telephone terminal GWT 3 .  
         [0037]      FIG. 2  is a block diagram showing the functional configuration of the main apparatus BT.  
         [0038]     The main apparatus BT has a function of exchanging and connecting the foregoing IP telephone terminals IPT 1  to IPT 3  and gateways GW 1  to GW 3 . In addition, the main apparatus BT includes several sections given below. One is an information receiving section  11  (hereinafter, referred to as receiving section  11 ). Another is a service determination section  12  (hereinafter, referred to as determination section  12 ). Another is a service providing section  13  (hereinafter, referred to as providing section  13 ). Another is a connecting section  14 .  
         [0039]     The main apparatus BT is further connected with a memory M. The memory M is provided with the following tables. One is a country-district classification table  21  (hereinafter, referred to as table  21 ). Another is an IP telephone terminal/country-district corresponding table (hereinafter, referred to as table  22 ). Another is a gateway/country-district corresponding table (hereinafter, referred to as table  23 ).  
         [0040]     As shown in  FIG. 3 , the table  21  is stored with service contents for each country-district. For example, the service contents are time difference from the standard time (Greenwich time), emergency number, A-Law/μ-Law classification, language, and country codes in international telephone.  
         [0041]     As depicted in  FIG. 4 , the table  22  is stored with data showing the corresponding relationship between phone numbers of IP telephone terminals IPT 1  to IPT 3  and country-district.  
         [0042]     As seen from  FIG. 5 , the table  23  is stored with data showing the corresponding relationship between identification phone numbers of gateways GW 1  to GW 3  and country-district.  
         [0043]     The receiving section  11  receives phone number and selected country-district information, which are sent from the IP telephone terminal IPT 1 .  
         [0044]     The determination section  12  reads the country-district information corresponding to the sent phone number from the table  22 . Thereafter, the section  12  determines service contents to be provided based on the country-district information.  
         [0045]     The providing section  13  provides a service suitable to the country-district associated by the IP telephone terminal IPT 1  based on the foregoing determination. In this case, the providing section  13  provides at least one of the following services to the IP telephone terminal IPT 1  based on the table  21  shown in  FIG. 3 . One is a service of displaying time information corresponding to the selected country-district. Another is an emergency number service corresponding to the selected country-district. Another is a voice signal service using coding corresponding to the selected country-district. Another is a voice recognition service corresponding to the selected country-district. Another is an international call service.  
         [0046]     The connecting section  14  connects the telephone terminal IPT 1  of a caller via the IP network IPN, the gateway GW 3  belonging to the specified one of country-district and the network INW 2  based on the table  23 , when a connection request is made from the IP telephone terminal IPT 1  to an external terminal of the network INW 1  of the specified one of countries and districts.  
         [0047]     As  FIG. 6  shows, each of the IP telephone terminals IPT 1  to IPT 3  comprises a LAN interface (I/F)  31 , an audio packet processor  32 , an audio input/output interface (I/F)  33 , a controller  34 , and an operation panel  35 .  
         [0048]     The LAN interface  31  receives and transmits various data items from and to the IP network IPN. That is, the LAN interface  31  extracts an audio packet and control data from the packets transferred from the IP network IPN. The audio packet and control data are supplied to the audio data processor  32  and the controller  34 , respectively. The LAN interface  31  multiplexes the data items supplied from the controller  34  with the audio packet supplied from the audio packet processor  32 , generating multiplex data. The multiplex data is transmitted from the LAN interface  31  to the IP network IPN.  
         [0049]     The audio packet processor  32  receives an audio packet from the LAN interface  31  and converts the audio packet into an analog received audio signal. The analog received audio signal is supplied to the audio input/output interface  33 . Further, the audio packet processor  32  receives an audio signal to be transmitted, from the audio input/output interface  33 , and converts this audio signal into an audio packet that can be easily transferred in the IP network IPN. The audio packet is supplied to the LAN interface  31 .  
         [0050]     A microphone  36  and a speaker  37  are connected to the audio input/output interface  33 . The audio input/output interface  33  receives an audio signal transmitted from the microphone  36  and supplies the same to the audio packet processor  32 . The interface  33  also receives an audio signal from the audio packet processor  32 , amplifies this signal, and supplies the signal to the speaker  37 . The speaker  37  generates a speech from the audio signal.  
         [0051]     The controller  34  comprises a CPU, a ROM and a RAM. The controller  34  executes programs (software) to control the other components and serves to achieve the communication between the IP telephone terminals IPT 1  to IPT 3  and the main apparatus BT via the IP network IPN.  
         [0052]     The operation panel  35  has an input device and a display. The input device may be a group of key switches. The display may be an LCD. The user operates the operation panel  35  to input various instructions to the controller  34 . Under the control of the controller  34 , various information items are given to the user.  
         [0053]     The controller  34  comprises a selecting section  341  and a transmitting section  342 . The selecting section  341  selects at least one of the countries and districts, to generate a selection signal. The transmitting section  342  transmits the selection signal to the main apparatus BT together with identification information of self telephone terminal.  
         [0054]     Various operations of the system having the foregoing configuration will be explained below.  
         [0055]      FIG. 7  is a flowchart to explain the operation by the main apparatus BT when updating time.  
         [0056]     In step ST 6   a , the main apparatus BT periodically updates the current time information of all IP telephone terminals IPT 1  to IPT 3  (step ST 6   b ). When giving the updated time information, the main apparatus BT confirms whether or not IP telephone terminals IPT 1  to IPT 3  exits (step ST 6   c ). Thereafter, the main apparatus BT reads the country-district classification belonging to each of the IP telephone terminals IPT 1  to IPT 3  (step ST 6   d ). The main apparatus BT makes reference to the table  21  to calculate a relative time difference between the self country-district classification and these IP telephone terminals (step ST 6   e ).  
         [0057]     The main apparatus BT adds or subtracts the time difference to or from the self local time, and gives the results as time information to each of the IP telephone terminals IPT 1  to IPT 3  (step ST 6   f ). For example, if the local time of the main apparatus BT is 12:00, the time difference from the IP telephone terminal IPT 3  (belonging to the East of US) is −3:00. (In other words, the main apparatus is delayed for three hours.) The main apparatus BT gives time information of 15:00 to the IP telephone terminal IPT 3 . On the other hand, the same operation as described above is carried out with respect to telephone terminals GWT 1  to GWT 3  connected to gateways GW 1  to GW 3 . More specifically, the main updates the current time information of all telephone terminals GWT 1  to GWT 3  based on country-district classification belonging to the connected gateways GW 1  to GW 3  (step ST 6   g ). When giving the updated time information, the main apparatus BT confirms whether or not telephone terminals GWT 1  to GWT 3  exits (step ST 6   h ). Thereafter, the main apparatus BT reads the country-district classification belonging to gateways GW 1  to GW 3 , which are connected with the telephone terminals GWT 1  to GWT 3  (step ST 6   i ). The main apparatus BT makes reference to the table  21  to calculate a relative time difference between the self country-district classification and these IP telephone terminals (step ST 6   j ).  
         [0058]     The main apparatus BT adds or subtracts the time difference to or from the self local time, and gives the results as time information to each of the telephone terminals GWT 1  to GWT 3  (step ST 6   k ).  
         [0059]     The optimum call path of the foregoing system will be explained below.  
         [0060]      FIG. 8  is a view to explain the connection operation in each call path.  
         [0061]     For example, the IP telephone terminal IPT 2  belonging to the west district of the country B makes local call, long-distance call to the east district of the country B, and international call to the country A.  
         [0062]      FIG. 9  is a flowchart to explain the operation by the main apparatus BT when making a local call following an automatic path select code using the IP telephone terminal IPT 2 .  
         [0063]     When the IP telephone terminal IPT 2  makes a local call following the automatic path select code, the main apparatus BT makes the following operation via steps ST 8   a  and ST 8   c . More specifically, the main apparatus BT analyzes the dial number of the IP telephone terminal IPT 2 , and determines that the call is a local call (step ST 8   d ). Then, the main apparatus BT reads the country-district classification belonging to the IP telephone terminal IPT 2  from the table  22  (step ST 8   e ). Further, the main apparatus BT reads the gateway number belonging to the same country-district as the IP telephone terminal IPT 2  from the table  23  (step ST 8   f ).  
         [0064]     The main apparatus BT selects and captures a circuit line from a public network line included in the selected gateway GW 2  (step ST 8   g ), and transmits a call dial (step ST 8   h  and step ST 8   i ).  
         [0065]      FIG. 10  is a flowchart to explain the operation by the main apparatus BT when making a long-distance call following an automatic path select code using the IP telephone terminal IPT 2 .  
         [0066]     When the IP telephone terminal IPT 2  makes a toll (long-distance) call following the automatic path select code, the main apparatus BT makes the following operation via steps ST 9   a  and ST 9   c . More specifically, the main apparatus BT analyzes the dial number of the IP telephone terminal IPT 2 , and determines that the call is a long-distance call (step ST 9   d ). The main apparatus BT determines the country-district belonging to the toll number district from a toll number.  
         [0067]     Then, the main apparatus BT reads the country-district classification belonging to the IP telephone terminal IPT 2  from the table  22  (step ST 9   e ). Further, the main apparatus BT reads the gateway number belonging to the determined country-district from the table  23  (step ST 9   f ).  
         [0068]     The main apparatus BT selects and captures a circuit line from a public network line included in the selected gateway (step ST 9   g ), and transmits a call dial (step ST 9   h  and step ST 9   i ).  
         [0069]      FIG. 11  is a flowchart to explain the operation by the main apparatus BT when making an international call following an automatic path select code using the IP telephone terminal IPT 2 .  
         [0070]     When the IP telephone terminal IPT 2  makes an international call following the automatic path select code, the main apparatus BT makes the following operation via steps ST 10   a  and ST 10   c . More specifically, the main apparatus BT analyzes the dial number of the IP telephone terminal IPT 2 , and determines that the call is an international call (step ST 10   d ). The main apparatus BT determines the country-district belonging to the caller from the country code.  
         [0071]     Then, the main apparatus BT reads the country-district classification belonging to the IP telephone terminal IPT 2  from the table  22  (step ST 10   e ). Further, the main apparatus BT reads the gateway number belonging to the country-district determined from the country code from the table  23  (step ST 10   f ).  
         [0072]     The main apparatus BT selects and captures a circuit line from a public network line included in the selected gateway (step ST 10   g ), and transmits a call dial (step ST 10   h  and step ST 10   i ).  
         [0073]      FIG. 12  is a flowchart to explain the operation by the main apparatus BT when making an emergency call using the IP telephone terminal IPT 2 .  
         [0074]     When the IP telephone terminal IPT 2  makes an emergency call, the main apparatus BT detects an emergency call code (step ST 11   a ). The main apparatus BT reads the country-district classification belonging to the IP telephone terminal IPT 2  from the table  22  (step ST 11   b ). Further, the main apparatus BT reads the gateway number belonging to the same country-district as the country-district classification belonging to the IP telephone terminal IPT 2  from the table  23  (step ST 10   c ).  
         [0075]     The main apparatus BT selects and captures a circuit line from a public network line included in the selected gateway (step ST 11   d ), and reads the emergency number corresponding to the country-district from the table  21  (step ST 11   e ). Thereafter, the main apparatus BT transmits the emergency call number via the captured line (step ST 11   f ).  
         [0076]     According to the first embodiment, when the IP telephone terminal IPT 2  makes local call, long-distance call, international call and emergency call, the main apparatus BT provides services based the country-district previously associated with the IPT 2 . Therefore, the user of the IP telephone terminal IPT 2  can receive a service suitable to a desired country-district.  
         [0077]     According to the first embodiment, when the IP telephone terminal IPT 2  makes voice communications through country-district, the main apparatus BT selects the lowest fee route. Therefore, the user of the IP telephone terminal IPT 2  can receive the optimum service at the lowest fee.  
       SECOND EMBODIMENT  
       [0078]      FIG. 13  is a schematic view showing the configuration of an IP telephone system according to a second embodiment of the present invention. In  FIG. 13 , the same reference numerals are used to designate parts identical to  FIG. 1 , and the details are omitted.  
         [0079]     The IP telephone system is connected with one gateway GW 1 , telephone terminal GWT 1 , IP telephone terminals IPT 1  and IPT 4  in a country N. The country-district classification of the foregoing gateway GW 1 , IP telephone terminals IPT 1  and IPT 4  is registered as “country N”. For example, when normal local call and long-distance call are made, the gateway GW 1  is selected as the capture line.  
         [0080]      FIG. 14  is a block diagram showing the functional configuration of the main apparatus BT 2 . In  FIG. 14 , the same reference numerals are used to designate parts identical to  FIG. 2 , and the details are omitted.  
         [0081]     The main apparatus BT 2  has a management section  15 . The management section  15  manages IP telephone terminal IPT 4  belonging to country N correspondingly to the West of country B.  
         [0082]     For example, a businessman visits a branch of the country N from the main office located in the West of the country B for a short term. The businessman does work while making contact with a customer in the West of the country B. In this case, the businessman makes a call to the customer using the telephone terminal GWT 1  located in the branch of the country N in the same manner as done in the main office. However, if the businessman dials the customer&#39;s phone number (local call), the telephone terminal GWT 1  located in the country N regards the gateway GW 1  as local gateway (capturing a line in public network call). For this reason, the call made by the businessman is treated as a call in the country N.  
         [0083]     In order to solve the foregoing problem, the following means are proposed. One is to make a call designating a call GW number before dial (GW designation call), and another is to make an international call (to country B). However, these means are lack for usability. In view of the foregoing circumstances, an IP telephone terminal IPT 4  for guest is newly registered (or the terminal using in the branch of the country N is converted into IP telephone terminal use). Further, the corresponding country-district classification of the IP telephone terminal IPT 4  is set as “the West of the country B”. By doing so, the IP telephone terminal IPT 4  functions as an IP telephone terminal connected to the network of the main office in the West of the country B although connected to an IP network IPN of the branch of the country N. More specifically, the language displayed on LCD is a language used in the country B, the calendar time is the local time of the West thereof, and the corresponding gateway is the gateway GW 2 .  
         [0084]     According to the second embodiment, the main apparatus BT 2  manages the IP telephone terminal IPT 4  so that the corresponding country-district classification is set as “the West of the country B”. By doing so, when making a call to the customer in the West of the country B, the businessman only dials the local number as usual using the IP telephone terminal IPT 4 . The main apparatus BT 2  selects a line captured from the corresponding country-district classification of the caller terminal in a local call from gateways belonging to the terminal. The calendar time displayed on the LCD is the local time of the West of the country B; therefore, there is no need of calculating the time difference between the customer and the businessman. (In other words, the businessman can directly see the local time of the customer.)  
       THIRD EMBODIMENT  
       [0085]      FIG. 15  is a schematic view showing the configuration of an IP telephone system according to a third embodiment of the present invention. In  FIG. 15 , the same reference numerals are used to designate parts identical to  FIG. 1 , and the details are omitted.  
         [0086]     According to the IP telephone system, the IP network IPN is connected with two main apparatuses BT 11  and BT 12 . The foregoing main apparatuses BT 11  and BT 12  are connected with each other using a dedicated line, and services are provided through both main apparatuses BT 11  and BT 12  (calling networking service).  
         [0087]     For example, the IP telephone terminal IPT 1  located in the country A makes a call to an external terminal connected to a public line network INW 2  of the country B. In this case, the main apparatus BT 11  of the country A has no gateway for the public network INW 2  in the country B. For this reason, the main apparatus BT 11  makes a call via the main apparatus BT 12  of the country B. In the conventional case, the main apparatus BT 11  dials a node identifier, and thereafter, dials automatic line select number and destination number.  
         [0088]     However, the IP telephone terminal IPT 1  belonging to the main apparatus BT 11  of the country A is not registered as data in the main apparatus BT 12  of the country B. For this reason, the main apparatus BT 11  can not specify a gateway number used for capturing the public line INW 2 .  
         [0089]     In order to solve the foregoing problem, a memory M 11  provided the main apparatus BT 11  is stored with the following table shown in  FIG. 16 . In the table, there is shown a country-district classification belonging to GW used for a call corresponding to a node identifier for identifying the B country node in gateways belonging to the B country node.  
         [0090]      FIG. 17  is a flowchart to explain the operation by the main apparatus BT 11  when a node identifier dials up using the IP telephone terminal IPT 1 .  
         [0091]     The IP telephone terminal IPT 1  dials up the node identifier of the country B node via the country A node (step ST 15   a ). The main apparatus BT 11  determines the country B node as the destination (step ST 15   b ). Then, the main apparatus BT 11  reads the country-district classification corresponding to the destination node identifier (step ST 15   c ). The main apparatus BT 11  gives the read country-district classification to the main apparatus BT 12  of the country B node (step ST 15   d ). Further, the main the main apparatus BT 11  gives the dial information received from the IP telephone terminal IPT 1  to the main apparatus BT 12  of the country B node (step ST 15   e  and step ST 15   f ).  
         [0092]     Thereafter, in the main apparatus BT 2 , an automatic line select function boots using the country B node by the automatic line select number. In this case, number analysis is made based on the given country-district classification, and a ling for making a call to the public network is selected.  
         [0093]     According to the third embodiment, the IP network IPN is provided with two main apparatuses BT 11  and BT 12 , and correspondence between country-district and these main apparatuses BT 11  and BT 12  is made. By doing so, if each country and district use one system in common, it is possible to specify main apparatus BT 11 , BT 12  used for each country and district. Thus, load given to one main apparatus is shared into two main apparatuses BT 11  and BT 12 . In addition, services used via each of IP telephone terminals IPT 1  to IPT 3  are clarified.  
       OTHER EMBODIMENT  
       [0094]     The present invention is not limited to the foregoing embodiments. According to the embodiments, when making a call through country or district, services suitable to the country or district are provided. For example, if the time of the IP telephone terminal is changed from the country N to the country B, it may be set to the local time of the country B by receiving time information from the main apparatus.  
         [0095]     Besides, various changes may be made within a range without diverging from the subject matter of the present invention. More specifically, various changes are possible in the configuration of the IP telephone system, the kind and configuration of the IP telephone terminal, service contents for each country-district and the procedure of using the services.  
         [0096]     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.