Switch device and system

The present invention relates to a PBX network, and the present invention relates to a PBX network composed of a plurality of PBXs connected to a public ISDN network.

[0002] FIG. 25 shows a configuration diagram of a PBX network. In the figure, each of PBX (private branch exchange) 10 and 12 is connected to the ISDN (Integrated Services Digital Network) public network 14, and the extension telephones are connected to each other, and the extension telephones 18 and 20 are connected to the ISDN public network 14. Connect to the telephones 22 and 24. In addition, PBXs 10 and 12 are connected to each other by ISDN relay lines 16 to form a PBX network.

[0003] In the conventional PBX network, the PBX number (for example, "700" for PBX10, "710" for PBX12, etc.) and the outgoing ID of the extension (for example) are included in the message to the opposite PBX connected by the ISDN relay line 16. Extension phone 18 stores "A", extension phone 20 stores "B", etc.) and notifies.

[0004] In the conventional PBX network, the subscriber telephone 22 of the ISDN public network 14 calls the extension telephone 20 via the ISDN public network 14, PBX10, ISDN relay line 16, and PBX12. Can be applied. However, in this case, the PBX10 number "700" and the identification code of the ISDN public network 14 are notified in the message from PBX10 to PBX12, and the calling ID for making a call to the subscriber telephone 22 (for example, "X"). ) Could not be notified, and it was inconvenient to make a call back from extension telephone 20 to subscriber telephone 22.

[0005] Further, the extension telephone 18 of the PBX 10 can make a call to the subscriber telephone 24 via the ISDN relay line 16, the PBX 12, and the ISDN public network 14. However, in this case, although the PBX10 number "700" and the extension ID "A" are notified in the message from PBX10 to PBX12, in the message from the ISDN public network 14 to the subscriber telephone 24, The outgoing ID for PBX12 is notified. For this reason, there is a problem that it is inconvenient to make a call back from the subscriber telephone 24 to the extension telephone 18 of the PBX 10.

[0006] The present invention has been made in view of the above points, and notifies the incoming telephone of the telephone number of the subscriber telephone or the dial-in number of the extension telephone in a call via the ISDN relay line of the PBX network. The purpose is to provide a PBX network that can display the above telephone number and make a call back, improving convenience.

[Means for Solving the Problems] The invention according to claim 1 is in a PBX network in which a plurality of private branch exchanges connected to an ISDN public network are connected by an ISDN relay line.<u style="single">The private branch exchange</u><u style="single"> When the call is made from the subscriber telephone of the ISDN public network, the above</u>The public ID information element, which is the telephone number of the subscriber telephone that sent the call setting message of the ISDN relay line protocol, is used as the additional service information element.<u style="single">Means to add and</u><u style="single"> An extension dial-in number conversion table that converts extension numbers of extension phones to dial-in numbers,</u><u style="single"> When a call is made from an extension phone The dial-in number of the call extension phone is added as an additional service information element to the call setting message of the ISDN relay line protocol.</u><u style="single">Have the means to do.</u>[0008] Therefore, when a call is made from a subscriber telephone of the ISDN public network to the extension telephone of the private branch exchange via the PBX network, the telephone number of the subscriber telephone can be notified to the incoming extension telephone, and the incoming call is received. It is possible to display the caller's phone number and make a call back with an extension phone.<u style="single">When you make a call from an extension phone to an extension phone of a private branch exchange via the PBX network, you can notify the dial-in number of the extension phone you called to the incoming extension phone, and dial the caller with this incoming extension phone. It is possible to display the extension number and make a call back.</u> The invention according to claim 2 is the PBX network according to claim 1.<u style="single"> The private branch exchange</u><u style="single"> When notified of the call setting protocol from the ISDN relay line</u>Public ID information element as the additional service information element<u style="single">Or dial in number</u>Set in the outgoing ID information element of the call setting message of the ISDN public network protocol<u style="single">Said</u>Make a call to a subscriber telephone on the ISDN public network<u style="single">Have means.</u>[0009] Therefore, when a call is made from a subscriber telephone of the ISDN public network to a subscriber telephone of the ISDN public network via the PBX network, the telephone number of the caller's subscriber telephone is added to the incoming subscriber telephone. Notifications can be made, and it is possible to display the caller's phone number and make a call back with this incoming subscriber phone.<u style="single">When you make a call from an extension phone to a subscriber phone on the ISDN public network via the PBX network, you can notify the dial-in number of the extension phone you made to the incoming subscriber phone. It is possible to display the dial-in number of the caller and make a call back.</u>To The invention according to claim 3 is the PBX network according to claim 1 or 2.<u style="single"> The private branch exchange</u><u style="single"> When the call is made from the subscriber telephone of the ISDN public network</u>After receiving an incoming call from the extension telephone of the private branch exchange and communicating, the call is made to the extension telephone of the PBX or the subscriber telephone of the ISDN public network through the ISDN relay line by the transfer operation.<u style="single">Have means.</u>[0010] Therefore, after receiving an incoming call from the ISDN public network subscriber telephone to the extension telephone of the private branch exchange of the PBX network and communicating, the call is transferred to the extension telephone or the ISDN public network subscriber telephone via the PBX network network. In this case, the transferred extension telephone or the subscriber telephone can be notified of the telephone number of the caller's subscriber telephone, and the caller's telephone number can be displayed or the call back can be made on the transferred telephone.

【0013】<u style="single"> The invention according to claim 4 is the PBX network according to claim 2.</u><u style="single"> The private branch exchange</u><u style="single"> It has a means for receiving a call setting protocol notification from the ISDN relay line, receiving an incoming call to the extension telephone of the exchange, communicating with the extension telephone, and then transmitting the call to the subscriber telephone of the ISDN public network by a transfer operation.</u>[0014] Therefore, when a call is made from the extension telephone to the extension telephone via the PBX network and then transferred to the subscriber telephone of the ISDN public network, the dial-in of the extension telephone made to the transferred subscriber telephone is made. The number can be notified, and the dial-in number of the caller can be displayed and the call back can be made with this transferred subscriber phone.

[Embodiment of the Invention] FIG. 2 shows a configuration diagram of an embodiment of the PBX network of the present invention. In the figure, each of PBX30 and 32 is connected to the ISDN public network 34, and connects the extension telephones to each other and the extension telephones 38 and 40 to the subscriber telephone connected to the ISDN public network 34. The PBXs 30 and 32 are connected to each other by an ISDN relay line 36 to form a PBX network.

[0016] FIG. 1 shows a block diagram of an embodiment of PBXs 30 and 32. In the figure, the line control unit 46 controls the line connection with the BTK (BRI station line) trunk card, the PTK (PRI station line) trunk card, and the ISDN public network 34. The line control unit 48 is composed of a DTLC (digital extension card) and a BLC (BRI extension card), and controls a line connection with an extension telephone 38 or the like. The line control unit 50 consists of an ITK (ISDN relay line trunk) and controls the line connection with the ISDN relay line. The NW (network unit) 52 connects the lines of the line control units 46, 48, 50, respectively, according to the control of the CC (central processing unit) 54.

[0017] In addition to performing the above line connection control, the CC 54 also performs message conversion control. This message conversion control is executed by the message receiving unit 60, the information element extraction unit 61, the information element control unit 62, the information element editing unit 63, and the message transmitting unit 64 in CC54. The MM (main memory) 56 is provided with an extension dial-in number conversion table 66 used for message conversion control, in addition to line connection information such as the DIL conversion table 65 used by the CC 54 for line connection control.

[0018] The format of the call setting (SETUP) message used on the ISDN relay line 36 in the present invention is shown in FIGS. 3 and 4, respectively. In FIG. 3, the outgoing ID information element M1 for identifying the outgoing call and the incoming ID information element M2 for identifying the incoming call are set in the code set 0 of the call setting message. Further, in the code set 7 which is an additional code set, a public ID information element M3 for identifying a telephone made by the ISDN public network 34 is set as an additional service information element.

Further, in FIG. 4, the outgoing ID information element M1 and the incoming ID information element M2 are set in the code set 0 of the call setting message, and the code set 7 has PBX30, 32 as additional service information elements. Dial-in number M4 is set for extension telephones 38 and 40. The message receiving unit 60 receives a message from the line control unit 46 or 50. This message is supplied to the information element extraction unit 61, and the outgoing ID information element M1, the incoming ID information element M2, the public outgoing ID information element M3, and the dial-in number M4 shown in FIGS. 3 and 4 are extracted from the call setting message. To. These extracted information elements are supplied to the information element control unit 62.

[0020] The information element control unit 62 searches the DIL conversion table 65 with the incoming ID information element M2 of the call setting message from the line control units 46 and 50, and converts it into the PBX number and the extension number of the PBX network. Further, if there is a call from the extension telephone through the line control unit 48, the extension dial-in number conversion table 66 is searched and the dial-in number of the extension telephone is obtained. The information element editorial unit 63 sets the PBX number and extension number obtained by searching the DIL conversion table 65 in the incoming ID information element M2 of the call setting message, and sets the extracted outgoing ID information element M1 in the public outgoing ID information element M1 of the call setting message. Set to ID information element M3, and set the extracted public ID information element M3 to call ID information element M1 of the call setting message. In addition, the extension number obtained by searching the extension dial-in number conversion table 66 is set in the dial-in number M4 of the call setting message, and the extracted dial-in number M4 is set in the outgoing ID information element M1 of the call setting message. Etc. are edited. The message transmission unit 64 sends the edited message to the line control unit 46 or 50.

[0021] FIG. 5 shows a flowchart in the case of making a call from the subscriber telephone 42 via the ISDN public network 34, PBX30, ISDN relay line 36, and PBX32. In this case, there are cases where the extension telephone 40 of the PBX 32 is called, and there are cases where the PBX 32 further calls the subscriber telephone 44 of the ISDN public network 34. First, a case of making a call to the extension telephone 40 as shown by a broken line in FIG. 6 will be described. FIG. 7 shows the information transmission sequence in this case, and the steps correspond to FIG. FIG. 8 is a diagram for explaining a call setting message in this case. Make a call from the subscriber telephone 42 of the ISDN public network 34 to the PBX 30 in step S10 of FIG. As a result, the ISDN public network 34 supplies the PBX30 with the configuration message shown in SM1 in FIG. In the SETUP message SM1, "044777XXXX" is set as the outgoing ID information element of code set 0, and "044777ABCD" is set as the incoming ID information element.

[0022] When an incoming call arrives at the PBX 30 in step S12, the PBX 30 extracts the outgoing ID information element and the incoming ID information element from the code set 0 of the call setting message SM1 in step S14. Next, using the incoming ID information element extracted in step S16, the DIL conversion table 65 is referred to and converted into the incoming ID information element via PBX32. Here, "044777ABCD" is converted to "710 + ZZZZ". Next, in step S18, the connection destination is determined from the incoming ID information. In this case, since the connection destination is the ISDN relay line 36, the process proceeds to step S20. In step S20, the call setting message for the ISDN relay line 36 is set. Here, the PBX number "700" of the transmission destination PBX32 and the station special number "0" indicating the connection line of the ISDN public network 34 of the PBX30 are extracted in the outgoing ID information element M1 of the code set 0 shown in FIG. Set the ID information element "044777XXXX". In addition, the incoming ID information element "710 + ZZZZ" via PBX32 converted in step S16 is set in the incoming ID information element SM2 of code set 0, and the public ID information element M3 of code set 7 is extracted in step S14. Set the calling ID information element "044777XXXX". In the next step S22, the call setting message shown in SM2 in FIG. 8 set as described above is used to make a call to PBX32.

Next, in step S24, PBX32 extracts the outgoing ID information element "044777XXXX" of the subscriber telephone 42 from the public ID information element of the code set 7 of the call setting message of the ISDN relay line 36, and also extracts the outgoing ID information element "044777XXXX" of the code set 0. Extract the incoming ID information element. Next, the connection destination is determined from the incoming ID information element extracted in step S26. In this case, since the connection destination is the extension telephone 40 of PBX32, the process proceeds to step S28. In step S28, the outgoing ID information element of the caller subscriber telephone 42 extracted in step S24 is set to the extension telephone 40 at the time of incoming call, and the outgoing ID information element "044777XXXX" of the subscriber telephone 42 is displayed on the extension telephone 40. Call back is possible. After that, in step S30, a call is made between the subscriber telephone 42 and the extension telephone 40 by answering the extension telephone 40.

Next, a case of making a call to the subscriber telephone 44 as shown by a broken line in FIG. 9 will be described. FIG. 10 shows the information transmission sequence in this case, and the steps correspond to FIG. FIG. 11 is a diagram for explaining a call setting message in this case. Make a call from the subscriber telephone 42 of the ISDN public network 34 to the PBX 30 in step S10 of FIG. As a result, the ISDN public network 34 supplies the PBX30 with the configuration message shown in SM3 in Figure 11. In the SETUP message SM3, "044777XXXX" is set as the outgoing ID information element of code set 0, and "044777 ****" is set as the incoming ID information element.

When an incoming call arrives at the PBX 30 in step S12, the PBX 30 extracts the outgoing ID information element and the incoming ID information element from the code set 0 of the call setting message SM1 in step S14. Next, using the incoming ID information element extracted in step S16, the DIL conversion table 65 is referred to and converted into the incoming ID information element via PBX32. Here, "044777 ****" is converted to "710 + 0 + 06949YYYY". Next, in step S18, the connection destination is determined from the incoming ID information. In this case, since the connection destination is the ISDN relay line 36, the process proceeds to step S20. In step S20, the call setting message for the ISDN relay line 36 is set. Here, the PBX number "700" of the transmission destination PBX32 and the station special number "0" indicating the connection line of the ISDN public network 34 of the PBX30 are extracted in the outgoing ID information element M1 of the code set 0 shown in FIG. Set the ID information element "044777XXXX". In addition, the incoming ID information element "710 + 0 + 06949YYYY" via PBX32 converted in step S16 is set in the incoming ID information element SM4 of the code set 0, and the public ID information element M3 of the code set 7 is set in step S14. Set the extracted calling ID information element "044777XXXX". In the next step S22, the call setting message shown by SM4 in FIG. 11 set as described above is used to make a call to PBX32.

Next, in step S24, PBX32 extracts the outgoing ID information element 044777XXXX of the subscriber telephone 42 from the public ID information element of the code set 7 of the call setting message of the ISDN relay line 36, and also extracts the outgoing ID information element 044777XXXX of the code set 0. Extract the incoming ID information element. Next, the connection destination is determined from the incoming ID information element extracted in step S26. In this case, since the connection destination is the subscriber telephone 44 of the ISDN public network 34, the process proceeds to step S32.

[0027] In step S32, the outgoing ID information element "044777XXXX" of the caller's subscriber telephone extracted in step S24 is set in the outgoing ID information element M1 of the code set 0 shown in FIG. 3, and the incoming ID extracted in step S24. Delete the PBX number and local special number "700 + 0+" from the information element "710 + 0 + 06949YYYY", set it to the arrival ID information element M2 of code set 0, and delete the code set 7 with SM5 in Fig. 11. Make a call to the ISDN public network 34 using the indicated call setting message.

Next, in step S34, when the subscriber telephone 44 receives an incoming call, the outgoing ID information element 044777XXXX given in the call setting message SM5 is set and displayed on the subscriber telephone 44. This makes it possible to make a call back. After that, in step S36, the subscriber telephone 44 answers and a call is made between the subscriber telephones 42 and 44. FIG. 12 shows a flowchart when making a call from extension telephone 38 via PBX30, ISDN36, and PBX32. In this case, the PBX 32 may make a call to the extension telephone 40, or the PBX 32 may make a call to the subscriber telephone 44 of the ISDN public network 34.

[0029] First, a case of making a call to the subscriber telephone 44 as shown by a broken line in FIG. 13 will be described. FIG. 14 shows the information transmission sequence in this case, and the steps correspond to FIG. FIG. 15 is a diagram for explaining a call setting message in this case. Make a call from extension 38 to PBX30 in step S40 of FIG. In step S42, the PBX 30 extracts the extension number DN and the incoming ID information element of the extension telephone 38 shown by SM6 in FIG. The incoming ID information elements are the PBX32 number "710", the local oscillator special number "0" connected to the ISDN public network 34, and the subscriber telephone 44 ID "06949YYYY".

[0030] In step S44, the PBX 30 converts the dial-in number of the extension telephone 38 by referring to the extension dial-in number conversion table 66 using the above-mentioned calling ID information element. Here, the extension number DN is converted to "044777AAAA". Next, in step S46, the connection destination is determined from the incoming ID information. In this case, since the connection destination is the ISDN relay line 36, the process proceeds to step S48. In step S48, the call setting message for the ISDN relay line 36 is set. Here, the PBX number 700 of the transmission destination PBX32 and the extension number DN of the extension telephone 38 are set in the outgoing ID information element M1 of the code set 0 shown in FIG. In addition, the incoming ID information element "710 + 0 + 06949YYYY" is set in the incoming ID information element SM2 of the code set 0, and the dial-in number "710 + 0 + 06949YYYY" converted to the dial-in number M4 of the extension of the PBX of the code set 7 in step S44. 044777AAAA "is set. In the next step S50, the call setting message shown by SM7 in FIG. 15 set as described above is used to make a call to PBX32.

Next, in step S52, the PBX 32 extracts the dial-in number 044777AAAA of the PBX extension of the code set 7 of the call setting message of the ISDN relay line 36, and also extracts the incoming ID information element of the code set 0. Next, the connection destination is determined from the incoming ID information element extracted in step S54. In this case, since the connection destination is the subscriber telephone 44 of the ISDN public network 34, the process proceeds to step S56.

[0032] In step S56, the dial-in number "044777AAAA" of the caller's extension telephone extracted in step S52 is set in the outgoing ID information element M1 of the code set 0 shown in FIG. 3, and the incoming ID information element extracted in step S52. The PBX number and local special number "700 + 0+" are deleted from "710 + 0 + 06949YYYY" and set in the incoming ID information element M2 of code set 0, and the code set 7 is deleted. Make a call to the ISDN public network 34 using the configuration message.

Next, in step S58, when the subscriber telephone 44 receives an incoming call, the outgoing ID information element given in the call setting message SM8, that is, the dial-in number "044777AAAA" is set and displayed on the subscriber telephone 44. This makes it possible to make a call back. After that, in step S60, the subscriber telephone 44 answers and a call is made between the extension telephone 38 and the subscriber telephone 44.

Next, a case of making a call to the subscriber telephone 40 as shown by a broken line in FIG. 16 will be described. FIG. 17 shows the information transmission sequence in this case, and the steps correspond to FIG. FIG. 18 is a diagram for explaining a call setting message in this case. Make a call from extension 38 to PBX30 in step S40 of FIG. In step S42, the PBX 30 extracts the extension number DN and the incoming ID information element of the extension telephone 38 shown by SM6 in FIG. The incoming ID information element is "710 + RRRR".

[0035] In step S44, the PBX 30 converts the dial-in number of the extension telephone 38 by referring to the extension dial-in number conversion table 66 using the above-mentioned calling ID information element. Here, the extension number DN is converted to "044777AAAA". Next, in step S46, the connection destination is determined from the incoming ID information. In this case, since the connection destination is the ISDN relay line 36, the process proceeds to step S48. In step S48, the call setting message for the ISDN relay line 36 is set. Here, the PBX number 700 of the transmission destination PBX32 and the extension number DN of the extension telephone 38 are set in the outgoing ID information element M1 of the code set 0 shown in FIG. In addition, the incoming ID information element "710 + RRRR" is set in the incoming ID information element SM2 of the code set 0, and the dial-in number "044777AAAA" converted in step S44 to the dial-in number M4 of the extension of the PBX of the code set 7 is set. To set. In the next step S50, the call setting message shown by SM7 in FIG. 18 set as described above is used to make a call to PBX32.

Next, in step S52, the PBX 32 extracts the dial-in number 044777AAAA of the PBX extension of the code set 7 of the call setting message of the ISDN relay line 36, and also extracts the incoming ID information element of the code set 0. Next, the connection destination is determined from the incoming ID information element extracted in step S54. In this case, since the connection destination is the extension telephone 40 of PBX32, the process proceeds to step S62. In step S62, the outgoing ID information element of the calling extension telephone 38 extracted in step S52, that is, the dial-in number is set to the extension telephone 40 when receiving an incoming call, and the dial-in number "044777AAAA" of the extension telephone 38 is displayed on the extension telephone 40. , Call back is possible. After that, in step S64, a call is made between the subscriber telephone 42 and the extension telephone 40 by answering the extension telephone 40.

FIG. 19 calls extension telephone 40 from extension telephone 38 via PBX30, ISDN relay line 36, and PBX32, and transfers the call to extension telephone 44 of public ISDN network 34 as shown by a broken line in FIG. The flow chart of the case is shown. In FIG. 19, the same parts as those in FIG. 12 are designated by the same reference numerals. FIG. 21 shows the information transmission sequence in this case, and the steps correspond to FIG. Make a call from extension 38 to PBX30 in step S40 of FIG. In step S42, the PBX 30 extracts the extension number DN and the incoming ID information element of the extension telephone 38 shown by SM6 in FIG. The incoming ID information element is "710 + RRRR".

[0038] In step S44, the PBX 30 converts the dial-in number of the extension telephone 38 by referring to the extension dial-in number conversion table 66 using the above-mentioned calling ID information element. Here, the extension number DN is converted to "044777AAAA". Next, in step S46, the connection destination is determined from the incoming ID information. In this case, since the connection destination is the ISDN relay line 36, the process proceeds to step S48. In step S48, the call setting message for the ISDN relay line 36 is set. Here, the PBX number 700 of the transmission destination PBX32 and the extension number DN of the extension telephone 38 are set in the outgoing ID information element M1 of the code set 0 shown in FIG. In addition, the incoming ID information element "710 + RRRR" is set in the incoming ID information element SM2 of the code set 0, and the dial-in number "044777AAAA" converted in step S44 to the dial-in number M4 of the extension of the PBX of the code set 7 is set. To set. In the next step S50, the call setting message shown by SM7 in FIG. 18 set as described above is used to make a call to PBX32.

Next, in step S52, the PBX 32 extracts the dial-in number 044777AAA of the extension of the PBX of the code set 7 of the call setting message of the ISDN relay line 36, and also extracts the incoming ID information element of the code set 0. Next, the connection destination is determined from the incoming ID information element extracted in step S54. In this case, since the connection destination is the extension telephone 40 of PBX32, the process proceeds to step S62. In step S62, the outgoing ID information element of the calling extension telephone 38 extracted in step S52, that is, the dial-in number is set to the extension telephone 40 when receiving an incoming call, and the dial-in number "044777AAAA" of the extension telephone 38 is displayed on the extension telephone 40. To. After that, in step S64, a call is made between the subscriber telephone 42 and the extension telephone 40 by answering the extension telephone 40.

[0040] If the subscriber of the subscriber telephone 42 finds out that he / she wants to make a call with the subscriber Y of the subscriber telephone 44 by this call, the extension telephone 40 to the subscriber telephone 44 of the ISDN public network 34 in step S70. Make a call by transfer operation to, and proceed to step S54. In this step S54, since the connection destination is the subscriber telephone 44 of the ISDN public network 34, the process proceeds to step S56.

[0041] In step S56, the dial-in number "044777AAAA" of the extension telephone of the originator extracted in step S52 is set in the calling ID information element M1 of the code set 0 shown in FIG. Set "06949YYYY", which was verbally transmitted to a person on the extension telephone of PBX32, in the incoming ID information element M2 of code set 0, and erased code set 7. Using the call setting message shown by SM8 in Fig. 15, the ISDN public network Call 34.

Next, in step S58, when the subscriber telephone 44 receives an incoming call, the outgoing ID information element given in the call setting message SM8, that is, the dial-in number "044777AAAA" is set and displayed on the subscriber telephone 44. This makes it possible to make a call back. After that, in step S60, the subscriber telephone 44 answers and a call is made between the subscriber telephone 44 and the extension telephone 40. Next, the process proceeds to step S74, after disconnecting the extension telephone 40 of the PBX 32, the extension telephone 38 and the subscriber telephone 44 are connected by the PBX 32, and a call is made between them.

[0043] FIG. 22 shows a flowchart when a subscriber telephone 42 makes a call to the extension telephone 38 via the ISDN public network 34 and the PBX 30 and transfers the telephone to the extension telephone 40 of the PBX 32 as shown in FIG. 23. In FIG. 22, the same parts as those in FIG. 5 are designated by the same reference numerals. FIG. 24 shows the information transmission sequence in this case, and the steps correspond to FIG. 22. In step S10 of FIG. 22, a call is made from the subscriber telephone 42 of the ISDN public network 34 to the PBX30. As a result, the ISDN public network 34 supplies the configuration message to the PBX30. In the SETUP message SM1, "044777XXXX" is set as the outgoing ID information element of code set 0, and "044777EFGH" is set as the incoming ID information element.

[0044] When an incoming call arrives at the PBX30 in step S12, the PBX30 extracts the outgoing ID information element and the incoming ID information element from the code set 0 of the call setting message SM1 in step S14. Next, using the incoming ID information element extracted in step S16, the DIL conversion table 65 is referred to and converted into the incoming ID information element via PBX32. Here, since the incoming ID information element indicates the extension telephone 38, the process proceeds to step S80, and the outgoing ID information element extracted from the call setting message is set and displayed on the extension telephone 38 when receiving a call. Next, in step S82, a call is made between the subscriber telephone 42 and the extension telephone 38 by answering the extension telephone 38. If the subscriber of subscriber telephone 42 finds out that he / she wants to make a call with the extension telephone of PBX32 by this call, the extension telephone 38 is transferred to the extension telephone 40 of PBX32 in step S84, and the call is made to the extension telephone 40 of PBX32. move on.

Next, in step S18, the connection destination is determined from the incoming ID information of the transfer. In this case, since the connection destination is the ISDN relay line 36, the process proceeds to step S20. In step S20, the call setting message for the ISDN relay line 36 is set. Here, the PBX number "700" of the transmission destination PBX32 and the station special number "0" indicating the connection line of the ISDN public network 34 of the PBX30 are extracted in the outgoing ID information element M1 of the code set 0 shown in FIG. Set the ID information element "044777XXXX". In addition, the incoming ID information element M2 of the code set 0 is set to "710 + ZZZZ" that the subscriber of the subscriber telephone 42 verbally conveys to the person of the extension telephone 38 of the PBX30 by a call, and the code set 7 is issued by the public. Set the outgoing ID information element "044777XXXX" extracted in step S14 in the ID information element M3. Make a call to PBX32 using the call setting message set as described above in the next step S22.

Next, in step S24, PBX32 extracts the outgoing ID information element 044777XXXX of the subscriber telephone 42 from the public ID information element of the code set 7 of the call setting message of the ISDN relay line 36, and also extracts the outgoing ID information element 044777XXXX of the code set 0. Extract the incoming ID information element. Next, the connection destination is determined from the incoming ID information element extracted in step S26. In this case, since the connection destination is the extension telephone 40 of PBX32, the process proceeds to step S28. In step S28, the outgoing ID information element of the caller subscriber telephone 42 extracted in step S24 is set to the extension telephone 40 at the time of incoming call, and the outgoing ID information element "044777XXXX" of the subscriber telephone 42 is displayed on the extension telephone 40. Call back is possible. After that, in step S30, a call is made between the subscriber telephone 42 and the extension telephone 40 by answering the extension telephone 40.

Next, the process proceeds to step S86, and after disconnecting the extension telephone 38 of the PBX30, the subscriber telephone 42 and the extension telephone 40 are connected by the PBX30, and a call is made between them.

[Effect of the Invention] As described above, the invention according to claim 1.<u style="single">According to</u>When a call is made from a subscriber telephone of the ISDN public network to the extension telephone of the private branch exchange via the PBX network network, the telephone number of the subscriber telephone can be notified to the incoming extension telephone, and the caller can use this incoming extension telephone. It is possible to display the phone number and make a call back<u style="single">When you make a call from an extension phone to a subscriber phone on the ISDN public network via the PBX network, you can notify the dial-in number of the extension phone you made to the incoming subscriber phone, and use this incoming subscriber phone. It is possible to display the dial-in number of the caller and make a call back.</u>【0050】<u style="single"> Further, according to the invention of claim 2,</u>When a call is made from an ISDN public network subscriber phone to an ISDN public network subscriber phone via the PBX network, the incoming subscriber phone can be notified of the caller's subscriber phone number, and this incoming call is received. It is possible to display the caller's phone number and make a call back on the subscriber's phone.<u style="single">When you make a call from an extension phone to a subscriber phone on the ISDN public network via the PBX network, you can notify the dial-in number of the extension phone you made to the incoming subscriber phone, and use this incoming subscriber phone. It is possible to display the dial-in number of the caller and make a call back.</u>【0051】<u style="single"> Further, according to the invention of claim 3,</u>Transferred when an incoming call is received from a subscriber telephone of the ISDN public network to the extension telephone of the private branch exchange of the PBX network and then transferred to the extension telephone or the subscriber telephone of the ISDN public network via the PBX network network. The telephone number of the caller's subscriber telephone can be notified to the extension telephone or the subscriber telephone, and the caller's telephone number can be displayed or the call back can be made with the transferred telephone.

【0055】<u style="single"> Further, according to the invention of claim 4,</u>If you make a call from an extension phone to an extension phone via the PBX network and then transfer it to a subscriber phone on the ISDN public network, you can notify the dial-in number of the extension phone you called to the transferred subscriber phone. It is possible to display the dial-in number of the caller and make a call back on the transferred subscriber phone.

BRIEF DESCRIPTION OF THE DRAWINGS [FIG. 1] FIG. 1 is a block diagram of a PBX used in the present invention.

FIG. 2 is a block diagram of the PBX network of the present invention.

FIG. 3 is a diagram showing a format of a call setting message.

FIG. 4 is a diagram showing a format of a call setting message.

FIG. 5 is a flowchart for explaining the present invention.

FIG. 6 is a diagram for explaining the present invention.

FIG. 7 is an information transmission sequence for explaining the present invention.

FIG. 8 is a diagram for explaining the present invention.

FIG. 9 is a diagram for explaining the present invention.

FIG. 10 is an information transmission sequence for explaining the present invention.

FIG. 11 is a diagram for explaining the present invention.

FIG. 12 is a flowchart for explaining the present invention.

FIG. 13 is a diagram for explaining the present invention.

FIG. 14 is an information transmission sequence for explaining the present invention.

FIG. 15 is a diagram for explaining the present invention.

FIG. 16 is a diagram for explaining the present invention.

FIG. 17 is an information transmission sequence for explaining the present invention.

FIG. 18 is a diagram for explaining the present invention.

FIG. 19 is a flowchart for explaining the present invention.

FIG. 20 is a diagram for explaining the present invention.

FIG. 21 is an information transmission sequence for explaining the present invention.

FIG. 22 is a flowchart for explaining the present invention.

FIG. 23 is a diagram for explaining the present invention.

FIG. 24 is an information transmission sequence for explaining the present invention.

FIG. 25 is a configuration diagram of a PBX network.

[Code description] 30,32 PBX34 ISDN public network 36 ISDN relay line 38,40 Extension telephone 42,44 Subscriber telephone 46 ~ 50 Line control unit 52 NW54 CC56 MM60 Message reception unit 61 Information element extraction unit 62 Information element control unit 63 Information element editorial unit 64 Message transmitter 65 DIL conversion table 66 Extension dial-in number conversion table