Abstract:
In an internal line control system, a telephone having an Internet protocol (IP) and capable of being connected to the Internet through the communication mode, includes means for storage of an IP address of a private branch exchange, and means for sending a switching request to the IP address of the private branch exchange while specifying identification information. Concurrently, a private branch exchange having an Internet protocol (IP) and connected to the Internet through the communication mode, includes means for storage of a correlation between the IP address of the telephone and an internal line number depending upon the identification information, and means for transmitting, depending upon the correlation between the IP address and the internal line number, a control signal and a speech communication signal for an internal line telephone of the internal line number to an address specified by the IP address. This allows a control to be switched over to the internal line telephone connected to the Internet so as to inherit various types of settings of the internal line telephone directly accommodated in the private branch exchange.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an internal line control system in a private branch exchange. More particular, the invention relates to an internal line control system in which a telephone connected to the Internet can be used as a substitute for an internal line accommodated in the private branch exchange.  
           [0002]    1. Description of the Prior Art  
           [0003]    In the prior-art private branch exchange system, audio communication is realized by an internal telephone accommodated at a physically predetermined position. Further, when the telephone connected to the Internet or LAN is registered as an internal line of a private branch exchange, a unique internal line number is recorded and used as the internal line in the private branch exchange.  
           [0004]    Accordingly, when the telephone is connected as the internal telephone to the Internet, it is necessary to record the unique internal line number as the internal line in the private branch exchange as described above. Hence, it is impossible to use the telephone as a substitute for an internal line of the private branch exchange which has been in use.  
           [0005]    In the prior-art system described above, there are problems in that, when the telephone is connected to the Internet as the internal telephone, it is impossible to use the telephone as a substitute for the internal line of the private branch exchange which has been in use, and inherit and employ each setting of services which have been set in the internal line of the private branch exchange.  
         SUMMARY OF THE INVENTION  
         [0006]    In view of the foregoing problems, it is an object of the present invention to provide an internal line control system in which a control can be switched over to an internal telephone connected to the Internet so as to inherit various types of settings of an internal line telephone directly accommodated in a private branch exchange, and the control can be switched over from the internal line in the own office and the internal line can be used as a substitutive internal line in any place so long as the telephone can be connected to the Internet.  
           [0007]    According to the present invention, for achieving the above-mentioned objects, there is provided an internal line control system in which a telephone having an Internet protocol (IP) and capable of being connected to the Internet through the communication mode includes means for storage of an IP address of a private branch exchange, and means for sending a switching request to the IP address of the private branch exchange while specifying identification information of an internal line of which switching is requested, accommodated in the private branch exchange, and a private branch exchange having an Internet protocol (IP) and connected to the Internet through the communication mode includes means for storage of a correlation between the IP address of the telephone and an internal line number depending upon the identification information, and means for transmitting, depending upon the correlation between the IP address and the internal line number, a control signal and a speech communication signal for an internal line telephone of the internal line number to an address specified by the IP address.  
           [0008]    In accordance with second aspect of the present invention, there is provided an internal line control system in which an internal line telephone corresponding to the internal line number includes posting means for posting a message in that a control is switched over to the telephone on the Internet, and the private branch exchange posts the switching by the posting means of the internal line telephone at a time of switching to the telephone on the Internet.  
           [0009]    Another aspect of the present invention, there is provided an internal line control system in which a computer having the function of transmitting/receiving sound is used as a substitute for the telephone on the Internet.  
           [0010]    Another aspect of the present invention, there is provided the internal line control system described above, in which the private branch exchange includes means for receiving authentication information transmitted with the switching request from the telephone connected to the Internet, and authenticating whether or not the switching request is acceptable depending upon the identification information.  
           [0011]    Another aspect of the present invention, there is provided the internal line control system in which an own IP address of the telephone is stored in a server on the Internet instead of the telephone, and the telephone obtains the own IP address from the server when presenting the switching request.  
           [0012]    Another aspect of the present invention, there is provided the internal line control system further including encrypting means for encrypting a control signal and a speech communication signal exchanged between the private branch exchange and the telephone, and decrypting means for decrypting the encrypted control signal and speech communication signal.  
           [0013]    Another aspect of the present invention, there is provided the internal line control system further including the plurality of private branch exchanges accommodating the internal line telephone, in which the telephone on the Internet includes means for specifying identification information of the internal telephone accommodated in the plurality of private branch exchanges, and requesting switching of the appropriate private branch exchange.  
           [0014]    Another aspect of the present invention, there is provided the internal line control system further including the plurality of private branch exchanges accommodating the internal line telephone, and the plurality of telephones on the Internet. In the internal line control system, the telephone on the Internet includes means for specifying identification information of the internal line telephone accommodated in the plurality of private branch exchanges, and requesting switching of the appropriate private branch exchange.  
           [0015]    Another aspect of the present invention, there is provided the internal line control system further including the plurality of private branch exchanges accommodating the internal line telephone. In the internal line control system, IP addresses of the plurality of private branch exchanges are stored in a server on the Internet, and the telephone obtains from the server the IP address of the private branch exchange when requesting switching.  
           [0016]    Another aspect of the present invention, there is provided the internal line control system in which the private branch exchange accepting the switching request from the telephone includes means for posting, when the internal line telephone is in use, a message to this effect to the telephone requesting the switching.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a block diagram showing a system configuration according to the first embodiment of the present invention;  
         [0018]    [0018]FIG. 2 is a diagram showing an illustrative structure of internal line identification information in the first embodiment of the present invention;  
         [0019]    [0019]FIG. 3 is a diagram for explaining an illustrative structure of IP address/internal line correspondence data;  
         [0020]    [0020]FIG. 4 is a diagram showing an illustrative structure of current internal line service condition data in the first embodiment of the present invention;  
         [0021]    [0021]FIG. 5 is a flowchart for explaining the operation of an internal line control system in the first embodiment of the present invention;  
         [0022]    [0022]FIG. 6 is a block diagram showing a system configuration according to the second embodiment of the present invention;  
         [0023]    [0023]FIG. 7 is a block diagram showing a system configuration according to the third embodiment of the present invention;  
         [0024]    [0024]FIG. 8 is a block diagram showing a system configuration according to the fourth embodiment of the present invention;  
         [0025]    [0025]FIG. 9 is a flowchart for explaining the operation of an internal line control system in the fourth embodiment of the present invention; and  
         [0026]    [0026]FIG. 10 is a block diagram showing a system configuration according to the fifth embodiment of the present invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    A detailed description will now be given of the present invention referring to the accompanying drawings.  
         [0028]    First Embodiment  
         [0029]    [0029]FIG. 1 is a block diagram showing a configuration of an internal line control system according to the first embodiment of the present invention.  
         [0030]    Referring to FIG. 1, in the internal line control system according to the first embodiment, a private branch exchange  11  is connected through a LAN card  18  to a substitutive internal line telephone  14  and a server  50  over the Internet, and the private branch exchange  11  is connected to an internal line telephone  12  and a maintenance terminal  19 .  
         [0031]    The private branch exchange  11  is connected to an Internet  40  through the LAN card  18  and a hub  30 , and the Internet  40  is connected to the substitutive internal line telephone  14  and the server  50 .  
         [0032]    In the embodiment, the private branch exchange  11  includes a signal converter  17 , an internal line identification information authenticating apparatus  20 , a subscriber data storage  21 , and an internal line information storage  22 .  
         [0033]    An internal line identification information  23  as shown in FIG. 2 is recorded in the subscriber data storage  21 . The internal line identification information  23  is recorded in a subscriber data storage  21  and contains information for each of internal line numbers (internal line  1 , . . . , internal line n), and is recorded as authentication information (such as ID or password) used for authentication of a switching request from the substitutive internal line telephone  14 . The authentication using the internal line identification information  23  prevents unauthorized access. The internal line identification information  23  is recorded in the subscriber data storage  21  through the operation of the maintenance terminal  19 .  
         [0034]    When the internal line identification information is sent with the internal line switching request from the substitutive internal telephone  14 , the internal line identification information authenticating apparatus  20  authenticates whether or not the sent internal line identification information is recorded in the internal line identification information  23  in the subscriber data storage  21 .  
         [0035]    As shown in FIG. 4, in the internal line information storage  22  is recorded, for each of the internal line numbers, current internal line service condition data  25  showing whether or not the internal telephone  12  is now in use or the substitutive internal line telephone  14  is in use as a substitute for the internal telephone  12 . The current internal line service condition data  25  is updated every time the internal line is switched over between the internal telephone  12  and the substitutive internal telephone  14 . Further, in the internal line information storage  22  is recorded IP address/internal line correspondence data  24  as shown in FIG. 3. When the internal line is switched over to the substitutive internal telephone  14  according to the switching request, in the IP address/internal line correspondence data  24  is recorded an IP address of the substitutive internal telephone  14  corresponding to the internal line number. Thereafter, when the internal line is switched back to the internal line telephone  12 , the IP address/internal line correspondence data  24  is erased.  
         [0036]    The substitutive internal telephone  14  connected to the Internet  40  includes a switching key  15  and an IP address/internal line identification information storage  16 .  
         [0037]    The switching key  15  is used to transmit the internal line switching request when the substitutive internal line  14  is used as a substitute for the internal line  12 . Though a separate key can be mounted as the switching key  15  to the substitutive internal line  14 , the function of the switching key  15  may be provided by, for example, combining keys previously attached to the substitutive internal line  14 .  
         [0038]    The server  50  includes an IP address storage portion  51 , and an IP address of the substitutive internal line  14  is stored in the IP address storage portion  51 . When presenting a switching request, the substitutive internal line  14  reads an own IP address from the IP address storage portion  51  of the server  50  and transmits the IP address.  
         [0039]    In the IP address/internal line identification information storage  16  is stored data correlating the IP address with the internal line identification information.  
         [0040]    In addition, the substitutive internal line  14  includes unillustrated means for transmitting and receiving a control signal and a speech communication signal between the substitutive internal line  14  and the private branch exchange  11  after the private branch exchange  11  accepts a connection request.  
         [0041]    Further, the internal line  12  includes a switching indicating lamp  13  indicating that the internal line is switched over to the substitutive internal line  14 .  
         [0042]    A description will now be given of the operation of the internal line control system having the above configuration referring to the flowchart shown in FIG. 5.  
         [0043]    In advance, by using the maintenance terminal  19  connected to the private branch exchange  11 , the internal line identification information  23  as shown in FIG. 2 is recorded in the subscriber data storage  21  in the private branch exchange  11  as authentication information for identification of the internal line.  
         [0044]    After the substitutive internal line telephone  14  is connected to the Internet, the switching key  15  is pressed (Step  501 ) to transmit, to the IP address of the private branch exchange  11  stored in the IP address/internal line identification information storage  16 , an internal line switching request containing both the own IP address obtained from the IP address storage portion  51  of the server  50  and the internal line identification information stored in the IP address/internal line identification information storage  16  (Step  502 ).  
         [0045]    In response to the internal line switching request from the substitutive internal line telephone  14 , the internal line identification information authenticating apparatus  20  in the private branch exchange  11  authenticates the received internal line identification information with reference to the internal line identification information  23  in the subscriber data storage  21  (Step  503 ).  
         [0046]    When both internal line identification information are identical and the request is authorized, the current internal line service condition data  25  in the internal line information storage  22  is updated to show that the substitutive internal line  14  is now in use (Step  504 ). Subsequently, in the IP address/internal line correspondence data  24  of the internal line information storage  22  is stored an IP address corresponding to an internal line number identical with that of the received internal line identification information (Step  505 ).  
         [0047]    Further, the private branch exchange  11  transmits to the substitutive internal line  14  a signal showing that the internal line switching request is accepted (Step  506 ), and turn on the switching indicating lamp  13  of the internal line telephone  12  (Step  507 ), thereby posting a message in that the internal line is switched over from the internal line  12  to the substitutive internal line  14 .  
         [0048]    Thereafter, when a control is requested for the internal line number for which the switching request is accepted in the private branch exchange  11 , the private branch exchange  11  recognizes, with reference to the current internal line service condition data  25 , that the substitutive internal line  14  is now in use as a substitute for the internal line  12 . The private branch exchange  11  assembles the control signal and the speech communication signal into an IP packet in the signal converter  17 , and sends the IP packet to the substitutive internal line  14  through the LAN card  18  and over the Internet  40 .  
         [0049]    The substitutive internal line telephone  14  is operated in response to the control signal from the private branch exchange  11  to transmit user&#39;s voice by using a sound signal.  
         [0050]    Further, by pressing the switching key  15 , the substitutive internal line  14  sends an internal line switching-back request to the private branch exchange  11 , and the private branch exchange  11  enables the internal line to be switched over from the substitutive internal line  14  to the internal line  12 . At the same time, the current internal line service condition data  25  is updated to show that the internal line  12  is now in use, the IP address/internal line correspondence data  24  is erased, and the switching indicating lamp  13  of the internal line telephone  12  is turned off. Thereafter, the control signal and the speech communication signal are exchanged between the private branch exchange  11  and the internal line  12 .  
         [0051]    According to the first embodiment, the internal line control system is operated as set forth above. Thus, the telephone substitutive internal line  14  can be used as a substitute for the internal line  12  in the own office in any place so long as the telephone can be connected to the Internet.  
         [0052]    Alternatively, in the above embodiment, the private branch exchange  11  may be provided with means for posting, if the internal line  12  is in use when presenting the switching request by pressing the switching key  15  of the substitutive internal line  14 , an in-use message to the substitutive internal line  14 . Concurrently, the substitutive internal line  14  may be provided with means for indicating the in-use message by, for example, turning on the lamp, or outputting the message depending upon the posting from the private branch exchange  11 .  
         [0053]    Second Embodiment  
         [0054]    A description will now be given of an internal line control system according to the second embodiment of the present invention. FIG. 6 is a block diagram showing a configuration of the internal line control system according to the second embodiment of the present invention.  
         [0055]    Referring to FIG. 6, in the internal line control system according to the second embodiment, encryption/decryption circuits  61 ,  62  are mounted to encrypt and decrypt a control signal and a speech communication signal exchanged between a private branch exchange  11  and a substitutive internal line  14 . The same reference numerals are used for component parts identical with those in the first embodiment of FIG. 1, and descriptions thereof are omitted.  
         [0056]    In the embodiment, the control signal and the sound signal are transmitted between the private branch exchange  11  and the substitutive internal line  14  through encryption by the encryption/decryption circuits  61 ,  62 , thereby preventing the control signal and the sound signal from leaking out over the Internet  40 . In the encryption/decryption circuits  61  and  62 , it is possible to employ one of cryptosystems (such as symmetrical key cryptosystem, and asymmetrical key cryptosystem) in the prior art.  
         [0057]    Third Embodiment  
         [0058]    A description will now be given of an internal line control system according to the third embodiment of the present invention. FIG. 7 is a block diagram showing a configuration of the internal line control system according to the third embodiment of the present invention.  
         [0059]    Referring to FIG. 7, in the internal line control system according to the third embodiment, a computer  70 , as well as a substitutive internal line  14 , can be used instead of an internal line telephone  12 . The same reference numerals are used for component parts identical with those in the first embodiment of FIG. 1, and descriptions thereof are omitted.  
         [0060]    The computer  70  including a personal computer (PC) and a mobile PC, is connected to the Internet  40 , and can be used for speech communication as a substitute for the internal line  12 . Hence, as in the substitutive internal line  14 , the computer  70  is provided with a switching key  15 , an IP address/internal line identification information storage  16 , and a speaker  73  and a microphone  74  for exchange of sound (speech communication).  
         [0061]    In the embodiment, as in the above-mentioned first embodiment, speech communication can be realized by switching over from the internal line  12  to the computer  70 . The operation is identical with that in the first embodiment shown in FIG. 5.  
         [0062]    Fourth Embodiment  
         [0063]    A description will now be given of an internal line control system according to the fourth embodiment of the present invention. FIG. 8 is a block diagram showing a configuration of the internal line control system according to the fourth embodiment of the present invention.  
         [0064]    Referring to FIG. 8, in the internal line control system according to the fourth embodiment, a plurality of private branch exchanges  11   a ,  11   b , . . . ,  11   n  are interconnected through a hub  30 . As shown in FIG. 8, the private branch exchanges  11   a ,  11   b , . . . ,  11   n  are connected to the Internet  40  through LAN cards  18   a  to  18   n , and respectively accommodate internal line  12   a  to  12   n . Each private branch exchange includes a signal converter  17 , an internal line identification information authenticating apparatus  20 , a subscriber data storage  21 , and an internal line information storage  22 .  
         [0065]    Further, instead of the IP address/internal line identification information storage  16  mounted in the substitutive internal line  14  in the first embodiment, a server  50   a  includes an IP address/internal line identification information storage  16   a . In the IP address/internal line identification information storage  16   a  are stored IP address and internal line identification information for each of the private branch exchanges  11   a ,  11   b , . . . ,  11   n . The same reference numerals are used for component parts identical with those in the first embodiment of FIG. 1, and descriptions thereof are omitted.  
         [0066]    In the embodiment, when switching of the internal line is requested from the substitutive internal line  14 , the substitutive internal line  14  obtains from the IP address/internal line identification information storage  16   a  of the server  50   a  the IP address and the internal line identification information of one of the private branch exchanges  11   a ,  11   b , . . . ,  11   n , upon which the internal line switching request should be made, and transmits the results to the appropriate private branch exchange.  
         [0067]    Further, the substitutive internal line  14  includes the switching key  15   a  for selective switching of the internal line telephones  12   a  to  12   n  accommodated in the plurality of private branch exchanges  11   a ,  11   b , . . . ,  11   n.    
         [0068]    A description will now be given of the operation of the internal line control system according to the fourth embodiment with reference to the flowchart of FIG. 9.  
         [0069]    In advance, by using maintenance terminals  19   a ,  19   b , . . . ,  19   n  connected to the private branch exchanges  11   a ,  11   b , . . . ,  11   n , internal line identification information  23  as shown in FIG. 2 is recorded, as authentication information for identification of the internal line, in the subscriber data storage  21  in each of private branch exchanges  11   a ,  11   b , . . . ,  11   n.    
         [0070]    After the substitutive internal line  14  is connected to the Internet, the switching key  15   a  is pressed corresponding to any one of the internal lines  12   a  to  12   n , to which the control should be switched over (Step  501 ). Subsequently, the substitutive internal line telephone  14  obtains from the IP address/internal line identification information storage  16   a  of the server  50  the IP address of one of the private branch exchanges  11   a ,  11   b , . . . ,  11   n  accommodating one of the internal line telephones  12   a  to  12   n , to which the control should be switched over (Step  901 ), and transmits to the obtained IP address of one of the private branch exchanges  11   a ,  11   b , . . . ,  11   n  an internal line switching request containing an own IP address obtained from an IP address storage portion  51  of the server  50   a  and internal line identification information stored in the IP address/internal line identification information storage  16   a  of the server  50   a  (Step  502 ).  
         [0071]    In later steps, the same operation is carried out as in the discussion with reference to FIG. 5.  
         [0072]    Fifth Embodiment  
         [0073]    A description will now be given of an internal line control system according to the fifth embodiment of the present invention. FIG. 10 is a block diagram showing a configuration of the internal line control system according to the fifth embodiment of the present invention.  
         [0074]    Referring to FIG. 10, in the internal line control system according to the fifth embodiment, a plurality of private branch exchanges  11   a ,  11   b , . . . ,  11   n  are interconnected through a hub  30 , and a plurality of substitutive internal line telephones  14   a ,  14   b , . . . ,  14   n  are interconnected over an Internet  40 . As shown in FIG. 10, the private branch exchanges  11   a ,  11   b , . . . ,  11   n  are connected to the Internet  40  through LAN cards  18   a  to  18   n , and respectively accommodate internal line telephones  12   a  to  12   n. Each private branch exchange includes a signal converter  17 , an internal line identification information authenticating apparatus  20 , a subscriber data storage  21 , and an internal line information storage  22 .    
         [0075]    Further, instead of the IP address/internal line identification information storage  16  mounted in the substitutive internal line  14  in the first embodiment, a server  50   a  includes an IP address/internal line identification information storage  16   a . In the IP address/internal line identification information storage  16   a  are stored an IP address and internal line identification information for each of the private branch exchanges  11   a ,  11   b , . . . ,  11   n . The same reference numerals are used for component parts identical with those in the first embodiment of FIG. 1, and descriptions thereof are omitted.  
         [0076]    In the embodiment, when switching of an internal line is requested from the substitutive internal line telephones  14   a  to  14   n , the substitutive internal line telephone obtains from the IP address/internal line identification information storage  16   a  of the server  50   a  the IP address and the internal line identification information of one of the private branch exchanges  11   a ,  11   b , . . . ,  11   n , of which switching is requested, and transmits the results to the appropriate private branch exchange.  
         [0077]    Further, the substitutive internal line telephones  14   a  to  14   n  include the switching keys  15   a  to  15   n  for selective switching of the internal lines  12   a  to  12   n  accommodated in the plurality of private branch exchanges  11   a ,  11   b , . . . ,  11   n.    
         [0078]    In the embodiment, the operation of the internal line control system is identical with that in the fourth embodiment. However, in the fifth embodiment, since the switching may be requested from the plurality of substitutive internal lines  14   a  to  14   n , the private branch exchange  11  may be provided with means for posting to the substitutive internal line telephone  14  a message in that the internal line telephone of which switching is requested is in use, or one internal line telephone is used as a substitute for another substitutive internal line telephone. Concurrently, the substitutive internal line telephone  14  may be provided with means for indicating the situation depending upon the posting from the private branch exchange  11  by, for example, turning on a lamp, or outputting the message.  
         [0079]    As set forth above, according to the present invention, it is possible to provide an effect in that the control can be switched over by the internal line telephone accommodated in the private branch exchange to use the telephone connected over the Internet, and the telephone can be used as a substitute for the internal line in the own office in any place so long as the telephone can be connected to the Internet.  
         [0080]    In addition, by mounting the encrypting means for encrypting the control signal and the speech communication signal exchanged between the private branch exchange and the telephone, and the decrypting means for decrypting the encrypted control signal and speech communication signal, it is possible to prevent the control signal and the sound signal from leaking out over the Internet.  
         [0081]    While preferred embodiments of the invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.