JP2008035476A - Call control method, computer program, and private branch exchange - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a private branch exchange capable of holding an IP telephone set therein as an extension terminal. <P>SOLUTION: When a call originator request is received from an IP telephone set of a calling source, the private branch exchange judges a classification of a call target terminal. If the call target terminal is a non-IP telephone set, a first voice session is established between the private branch exchange and the IP telephone set of the calling source via packet line while a calling is established between the private branch exchange and the call target non-IP telephone. Subsequently a voice path by the first voice session is connected to a voice path by the establishment of the calling to establish a voice path. If the call target terminal is an IP telephone set, a first voice session is established while a second voice session is established between the private branch exchange and the call target IP telephone set via packet line. Subsequently a voice path by the first voice session is connected to a voice path by the second voice session to establish a voice path. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a private branch exchange for telephone communication, and more particularly to a private branch exchange that accommodates both IP telephones and non-IP telephones.

  In a private branch exchange system using a circuit switching method, generally, a private branch exchange centrally manages individual states of telephone terminals. The private branch exchange manages the call state at each telephone terminal and performs call control.

  On the other hand, in an IP telephone system in which an IP telephone terminal and an IP telephone server that manages the system are arranged on an IP (Internet Protocol) network, call control, call state management, and exchange of RTP (Real-time Transport Protocol) The IP telephone terminal makes a determination regarding the above.

  As a conventional technique for accommodating an IP telephone terminal in a circuit-switched private branch exchange, for example, Patent Document 1 is known.

JP 2003-273899 A

  Conventionally, when an IP telephone terminal is accommodated in a circuit-switched private branch network, it is accommodated in the private branch exchange via an IP telephone server. In such a system, the IP telephone terminal cannot be handled as the extension telephone terminal of the private branch exchange because of the difference in the management system such as the call control of the telephone terminal as described above. As a result, even the private branch exchange of the so-called key telephone system cannot use the function from the IP telephone terminal.

  The present invention has been made in view of such a situation, and a problem to be solved by the present invention is to provide a private branch exchange capable of accommodating an IP telephone as an extension terminal.

  In order to solve the above problems, the present invention provides the following call control method, computer program and private branch exchange.

  That is, in a call control method performed in a private branch exchange having both a packet line interface and a circuit switched line interface, the private branch exchange receives a call request from a caller IP telephone, and the private branch exchange calls the call destination terminal. If the call destination terminal is a non-IP telephone as a result of the determination, a first voice session is established via the packet line between the private branch exchange and the caller IP telephone. A call source IP telephone is established by establishing a call via a circuit-switched line between the exchange and the call destination non-IP telephone and connecting the voice path by the first voice session and the voice path by the call establishment. Establishing a voice path between the caller and the callee non-IP telephone, and, if the callee terminal is an IP telephone as a result of the determination, establishes a first voice session while calling with the private branch exchange. By establishing a second voice session via a packet line with the destination IP telephone and connecting the voice path by the first voice session and the voice path by the second voice session, the caller IP A call control method comprising: establishing a voice path between a telephone and a call destination IP telephone.

  The private branch exchange includes a storage device that stores a table for managing registration information of both IP telephones and non-IP telephones accommodated as extension terminals, and the private branch exchange determines whether the calling terminal is based on the call request and the table. The type determination may be performed.

  If the call destination terminal is an IP phone as a result of the determination, the private branch exchange changes at least part of the content of the call request received from the caller IP phone, and makes a call with the private branch exchange based on the changed call request. A second voice session may be established peer-to-peer with the called IP phone.

  According to another aspect of the present invention, there is provided a computer program for executing a call control process in a private branch exchange control device having both a packet line interface and a circuit switched line interface, based on a call request received from a caller IP telephone. If the call destination terminal is a non-IP telephone as a result of the determination of the type of the call destination terminal and the determination result is a first voice session via a packet line between the private branch exchange and the caller IP telephone. On the other hand, by establishing a call via a circuit switched line between the private branch exchange and the call destination non-IP telephone, and connecting the voice path by the first voice session and the voice path by the call establishment, A process of establishing a voice path between the caller IP telephone and the callee non-IP telephone, and if the callee terminal is an IP telephone as a result of the determination, the first voice session is On the other hand, a second voice session is established between the private branch exchange and the call destination IP telephone via a packet line, and a voice path by the first voice session and a voice path by the second voice session are established. A computer program is provided that causes a computer to execute processing for establishing a voice path between a caller IP telephone and a callee IP telephone by connecting.

  Also provided is a private branch exchange that includes a recording medium in which such a computer program is recorded and performs call control according to the computer program.

  Further, in the private branch exchange, a communication protocol processing unit that transmits and receives a call control message according to a communication protocol of an IP telephone connected through the packet line interface, the circuit switched line interface, and the packet line interface, and a communication protocol processing unit The received call control message is converted into a signal that can be interpreted by the call control unit, and the signal received from the call control unit is received from an IP telephone and an IP conversion corresponding unit that converts the signal received from the call control unit into a call control message in a communication protocol A codec that performs voice encoding and decoding, and a call control unit that determines a type of a call destination terminal based on a call request received from a caller IP telephone. As a result, when the call destination terminal is a non-IP phone, a packet line is passed between the private branch exchange and the caller IP phone. While establishing a voice session for one, a call is established between the private branch exchange and the non-IP telephone to be called via a circuit switched line, and a voice path for the first voice session and a voice path for call establishment are established. By establishing a connection, a voice path is established between the caller IP telephone and the callee non-IP telephone. If the callee terminal is an IP telephone as a result of the determination, the first voice session is established. By establishing a second voice session via a packet line between the private branch exchange and the call destination IP telephone, and connecting the voice path by the first voice session and the voice path by the second voice session A private branch exchange is characterized in that a voice path is established between a caller IP telephone and a callee IP telephone.

  The present invention also relates to a call control method performed by a private branch exchange having both a packet line interface and a circuit switched line interface, wherein the private branch exchange receives a call request from a caller IP telephone, and A step of determining a type of a call destination terminal, and if the call destination terminal is a non-IP telephone as a result of the determination, a first voice session is established between the private branch exchange and the call source IP telephone via a packet line On the other hand, by establishing a call via a circuit-switched line between the private branch exchange and the call destination non-IP telephone, and connecting the voice path by the first voice session and the voice path by the call establishment, Establishing a voice path between the caller IP phone and the callee non-IP phone, and if the callee terminal is an IP phone as a result of the determination, between the caller IP phone and the callee IP phone Establishing a voice path between the calling IP phone and the called non-IP phone by establishing a third voice session over the packet line peer-to-peer. Provide a control method.

  The establishment of the third voice session includes a step in which the caller IP telephone transmits a first message for notifying a call request to the private branch exchange (step S81), and the private message is transmitted according to the first message. RTP (Real-time Transport Protocol) reception capability of the caller IP phone that is notified from the exchange to the callee IP phone at the same time as the first message or stored in advance in the storage device of the private branch exchange, and A step of transmitting a second message notifying the call request (step S93), and in response to the second message, the call destination IP telephone notifies the private branch exchange of affirmation of the call request. 3 message (step S94), and in response to the third message, the private branch exchange sends the third message to the calling IP phone. A step of transmitting a fourth message for notifying the RTP reception capability of the caller IP phone, the IP address of the caller IP phone, and the call request response that is notified at the same time as the message or stored in the storage device in advance. (Step S106) and the step of establishing a voice path by performing peer-to-peer RTP communication between the caller IP phone and the callee IP phone in response to the fourth message (Step S107) Can be considered.

  The private branch exchange includes a storage device that stores a table for managing registration information of both IP telephones and non-IP telephones accommodated as extension terminals, and the private branch exchange determines whether the calling terminal is based on the call request and the table. The type determination may be performed.

  According to another aspect of the present invention, there is provided a computer program for executing a call control process in a private branch exchange control device having both a packet line interface and a circuit switched line interface, based on a call request received from a caller IP telephone. If the call destination terminal is a non-IP telephone as a result of the determination of the type of the call destination terminal and the determination result is a first voice session via a packet line between the private branch exchange and the caller IP telephone. On the other hand, by establishing a call via a circuit switched line between the private branch exchange and the call destination non-IP telephone, and connecting the voice path by the first voice session and the voice path by the call establishment, If the call destination terminal is an IP phone as a result of the process of establishing a voice path between the call source IP phone and the call destination non-IP phone, and A feature of causing a computer to execute processing for requesting that one of the destination IP phones establish a third voice session via the packet line with the other IP phone via a packet line. A computer program is provided.

  Furthermore, the present invention provides a private branch exchange that includes a packet line interface, a circuit switched line interface, a communication protocol processing unit that transmits and receives a call control message according to a communication protocol of an IP telephone connected via the packet line interface, An IP conversion corresponding unit that converts a call control message received by the protocol processing unit into a signal that can be interpreted by the call control unit, and converts a signal received from the call control unit into a call control message in a communication protocol; Call control comprising: a codec for encoding and decoding voice received from a telephone; and a call control unit for determining a type of a call destination terminal based on a call request received from a caller IP telephone. If the call destination terminal is a non-IP phone as a result of the determination, the packet is transmitted between the private branch exchange and the caller IP phone. A first voice session over the network, while establishing a call over the circuit-switched line between the private branch exchange and the callee non-IP telephone, and a voice path through the first voice session and a call establishment A voice path is established between the caller IP telephone and the callee non-IP telephone by connecting the voice path, and if the callee terminal is an IP telephone as a result of the determination, the caller IP telephone and Establishing a voice path between the caller IP telephone and the callee non-IP telephone by establishing a third voice session via the packet line between the callee IP telephone and peer-to-peer. A private branch exchange is provided.

  Further, the present invention provides a computer program executed by a processing device of an IP telephone, prior to or simultaneously with notification of a call request to the other IP telephone, receiving the RTP of the IP telephone. A process for notifying the private branch exchange of the capability, a process for receiving a call request response from the other IP telephone in response to the call request via the private branch exchange, and a call request response in response to the call request response At the same time, based on the RTP reception capability of the other IP telephone and the IP address of the other IP telephone, which are notified at the same time or stored in the storage device of the private branch exchange prior to the call request response, A computer program for causing a processing device to execute processing for establishing a voice session peer-to-peer with another IP telephone; and Providing an IP telephone provided with a recorded computer-readable recording medium and the processing device computer program.

  According to the present invention, an IP telephone can be accommodated in a private branch exchange as an extension telephone terminal, and an extension call can be performed under the management of the other private IP telephone and non-IP telephone accommodated in the private branch exchange.

  Example 1 of the present invention will be described below.

  As shown in FIG. 1, the key telephone system 1 of the present invention includes a private branch exchange 2, a hub 3, IP telephones 4 and 5, and button telephones 6 and 7. The key telephones 6 and 7 are circuit switching type telephone terminals. Here, in order to simplify the explanation, two IP telephones and two key telephones are used. However, the description of this embodiment is applicable if the same system has two or more telephones including at least one IP telephone. .

  The private branch exchange 2 will be described with reference to FIG.

  The private branch exchange 2 includes a main board 21. The main board 21 includes a LAN interface unit 22, a communication protocol processing unit 23, an IP conversion support unit 24, a call control unit 25, a storage unit 26, a key telephone support unit 27, and a circuit switching network interface unit 28. The LAN interface unit 22 transmits and receives data by IP (Internet Protocol). The communication protocol processing unit 23 functions as a client of a communication protocol corresponding to the IP telephone, and interprets and responds to a call control message from the IP telephone. This corresponds to a user agent in a SIP (Session Initiation Protocol) network. The IP conversion support unit 24 converts the call control message conforming to the communication protocol of the IP telephone and the control signal of the call control unit 25 bidirectionally. The call control unit 25 performs call processing and other processing of the entire key telephone system 1 including the IP telephones 4 and 5 in accordance with a program built therein or stored in the storage unit 26 in advance. The storage unit 26 stores a management table that stores call states and other states of all telephone terminals in the key telephone system 1 including both IP telephones and button telephones. Specifically, the management table stores an extension telephone number, a call state, a terminal type, and, if the terminal type is an IP telephone, further IP addresses for all the terminals accommodated. The extension telephone number is a unique number in the key telephone system 1. The call state includes standby, calling, and talking. Terminal types include button telephones, IP telephones, and single telephones. The key telephone corresponding unit 27 controls the key telephones 6 and 7. The circuit switching network interface unit 28 connects signal lines to the key telephones 6 and 7.

  The private branch exchange 2 includes a VoIP (Voice over Internet Protocol) compatible board 29. The VoIP compatible board 29 includes an RTP transmission / reception unit 30 and a LAN interface unit 31. The RTP transceiver 30 transmits / receives RTP (Real-time Transport Protocol). Performs sampling, quantization, coding, and packetization of voice information. Further, the packet is decoded. The LAN interface unit 31 transmits and receives data by IP.

  In order to use the IP telephones 4 and 5 as extension telephone terminals, it is necessary to register with the private branch exchange 1. Next, the operation of the private branch exchange 2 when registering the IP telephone 4 as an extension telephone terminal will be described with reference to FIG.

  The IP telephone 4 transmits a registration request as a call control message to the private branch exchange 2 via the hub 3 (step S1). This call control message stores a caller address, an IP address, and the like in a communication protocol used by the IP telephone 4.

  This call control message is received by the communication protocol processing unit 23 via the LAN interface unit 22. The communication protocol processing unit 23 analyzes the call control message, extracts a registration request, a caller address, and the like, and passes them to the IP conversion handling unit 24 (step S2).

  In response to the registration request, the IP conversion support unit 24 registers the extension telephone number, IP address, and terminal type corresponding to the caller address of the IP telephone 4 in the management table (steps S3 and S4). The extension telephone number corresponding to the caller address may be a unique number calculated based on the caller address, or the caller address and the extension telephone registered in the storage unit 26 in advance. It may be obtained by referring to the correspondence with the number or may be obtained from the IP telephone 4.

  Next, the operation of the key telephone system 1 when a call is made from the IP telephone 4 to the key telephone 6 after the above registration operation will be described with reference to FIG.

  A call request is sent from the IP telephone 4 to the private branch exchange 2 as a call control message (step S10). The call request includes information such as a call destination address of the key telephone 6 on the communication protocol, a call destination address of the IP telephone 4, and that the IP telephone 4 can receive voice RTP.

  The communication protocol processing unit 23 that has received the call control message via the LAN interface unit 22 analyzes the call control message, extracts a call request, and passes it to the IP conversion correspondence unit 24 (step S11).

  Upon receiving the call request, the IP conversion support unit 24 converts the call request into a signal that can be interpreted by the call control unit 25 and passes it to the call control unit 25 (step S12).

  In response to this, the call control unit 25 executes a calling process. First, in the management table stored in the storage unit 26, the terminal type corresponding to the call destination address included in the call request is confirmed (steps S13 and S14). Here, the terminal type is a non-IP telephone. In this case, the call control unit 25 determines whether or not it is possible to make a call (steps S15 and S16).

  If it is determined that the call can be made, the call control unit 25 transmits a call request response to the IP conversion handling unit 24 (step S17). The IP conversion corresponding unit 24 passes the call request response to the communication protocol processing unit 23 (step S18), and the communication protocol processing unit 23 packetizes the call request response according to a predetermined communication protocol and transmits it to the IP telephone 4 (step S18). S19). Further, the IP conversion corresponding unit 24 instructs the RTP transmitting / receiving unit 30 to start RTP transmission / reception processing (step S20).

  If it is determined that the call can be made, the call control unit 25 instructs the key telephone corresponding unit 27 to send a calling signal to the key telephone 6 which is a call destination terminal (step S21). In response to this instruction, the key telephone corresponding unit 27 sends a calling signal to the key telephone 6 via the circuit switching network interface unit 28 (step S22).

  Receiving the call signal, the key telephone 6 calls the called party by ringing a ringing tone or the like. In response to this, when the called party goes off-hook, the key telephone 6 sends a call response to the private branch exchange 2 (step S23).

  When the circuit switching network interface unit 28 receives the call response, the call control unit 25 is notified via the key telephone corresponding unit 28 (step S24). Thereby, the call control unit 25 establishes a call between the IP telephone 4 and the key telephone 6 (step S25). When viewed from the IP telephone 4, a call in the key telephone system 1 is similar to communicating with an opposite IP telephone in a peer-to-peer manner. When the call is established, the call control unit 25 updates the call state of the IP telephone 4 and the button telephone 6 in the management table of the storage unit 26 during a call and updates it to a standby state when the call ends.

  With this operation, an extension call between an IP telephone and a non-IP telephone such as a key telephone can be performed under the control of a private branch exchange.

  Next, the operation of the key telephone system 1 when making an extension call from the IP telephone 4 to another IP telephone 5 will be described with reference to FIG. It is assumed that both IP telephones 4 and 5 have completed the registration process of FIG.

  When the IP telephone 4 transmits a call request as a call control message to the private branch exchange 2 (step S30), the call request is transferred to the IP conversion corresponding unit 24 via the LAN interface unit 22 and the communication protocol processing unit 23. (Step S31). In response to this, the IP conversion handling unit 24 stores the call request and the ID issued for the call in association with each other, and notifies the call control unit 25 of the call request (step S32). This ID is an identifier issued for each call.

  In response to the call request, the call control unit 25 accesses the storage unit 26, refers to the terminal information of the IP telephone 5 that is the call destination terminal specified in the call request, and determines the terminal type of the IP telephone 5 Confirm (steps S33 and S34). Here, the terminal type is an IP telephone. In this case, the call control unit 25 transmits the call request again to the IP conversion handling unit 24 (step S35).

  When receiving the call request, the IP conversion handling unit 24 updates a part of the call request stored in advance (step S36). The call request includes the IP address of the IP telephone 4 that is the call source and information indicating the presence or absence of the voice RTP reception function. The IP conversion correspondence unit 24 replaces the information regarding the IP telephone 4 with the information regarding the private branch exchange 2. That is, the caller IP address in the call request is rewritten to the IP address of the private branch exchange 2, and the presence or absence of the voice RTP reception function is rewritten to a value corresponding to the function of the RTP transceiver unit 30. The updated call request is transmitted to the IP telephone 5 via the communication protocol processing unit 23, the LAN interface unit 22, and the hub 3 (steps S37 and S38).

  The IP telephone 5 performs call control (step S39) using a general IP telephone, and establishes a call with the RTP transceiver 30 via the hub 3 and the LAN interface 31. The call control unit 25 connects the IP telephone 4 and the IP telephone 5, and a call is established between the IP telephone 4 and the IP telephone 5 (step S40).

  In this way, the two IP telephones 4 and 5 accommodated in the private branch exchange 2 as extension telephone terminals make an extension call via the private branch exchange 2. Here, the IP telephones 4 and 5 do not directly exchange call control messages or voice RTP on a peer-to-peer basis. For this reason, the private branch exchange 2 can grasp the call state and voice call state of the IP telephone, and can make an extension call under the management.

  In the first embodiment, the voice path from the IP telephone is terminated by a VoIP compatible board provided in the private branch exchange. For this reason, when an extension call is made from an IP telephone registered as an extension terminal to another IP telephone registered for extension, communication with each IP telephone is performed and RTP processing for connecting them is performed on the VoIP compatible board. Need to be executed. That is, the VoIP-compatible board needs to handle the same number of RTPs as the IP telephone that establishes the extension call at the same time. As the number of IP telephones that establish an extension call at the same time increases, more resources are required for the VoIP compatible board to execute the RTP process.

  In the present embodiment, during call control, when making a call from an IP telephone, the connection of the voice path is determined according to the type of the destination telephone, and the call is dynamically made with the VoIP compatible board by the voice reception capability of the other party. Perform switching control. This makes it possible to establish an extension call without consuming VoIP-compatible board resources in the private branch exchange.

  This embodiment will be described below. Similar to the first embodiment, this embodiment will be described based on the key telephone system 1 shown in FIG. 1 and the private branch exchange 2 shown in FIG. It is assumed that IP telephones 4 and 5 are registered in advance as extension telephones in accordance with the procedure shown in FIG. Compared with the first embodiment, the second embodiment is different in operation when calling another extension telephone from an IP telephone registered as an extension telephone.

  First, the operation when the extension telephone of the call destination is a key telephone will be described with reference to FIG.

  The IP telephone 4 transmits a call control message, which is a call request message based on IP, to the private branch exchange 2 (step S61). The call request message includes a message indicating the transmission destination (destination dial) and the voice path (RTP) reception capability of the IP telephone 4 itself. Here, the transmission destination is the extension telephone number of the key telephone 6. The RTP reception capability is, for example, a priority codec, a payload size, and a reception IP address.

  A call control request message from the IP telephone 4 is received by the LAN interface unit 22 and passed to the communication protocol processing unit 23. When the communication protocol processing unit 23 interprets the received call control message and determines that it is a call request message, the communication protocol processing unit 23 stores the RTP reception capability of the IP telephone 4 in the storage unit 26 together with the extension telephone number (step S62). A call request is notified to the call control unit 25 via the IP conversion correspondence unit 24 (steps S63 and S64).

  In response to this, the call control unit 25 performs dial analysis processing. Dial analysis processing corresponds to steps S65 and S66. Referring to FIG. 5, the call control unit 25 extracts a destination dial from the call request and performs a determination on the extracted destination dial based on the management table registered in the storage unit 26. More specifically, it is determined whether the destination dial is an extension telephone number, or an outside line number, or a special number process in which the private branch exchange 2 provides a predetermined service process to an extension terminal in response to a dial of a predetermined number (step If the destination dial is an extension telephone number, it is determined whether or not the terminal having the extension telephone number is an IP telephone (step T2). Now, the destination dial is the extension telephone number of the key telephone 6 which is an extension telephone. In this case, the call control unit 25 shifts to VoIP compatible board call processing transmission (step T3). As a result of the dial analysis process, when the destination dial is an outside line number or a special number, a transmission process corresponding to each is performed.

  In VoIP compatible board call processing transmission, the call control unit 25 refers to the management table in the storage unit 26 to check the call state of the key telephone 6, and if the key telephone 6 is in a standby state, the call telephone corresponding unit 27 is activated. Then, the key telephone 6 is called (steps S67 to S70).

  When the handset of the key telephone 6 is off-hooked, the key telephone 6 transmits a call response to the private branch exchange 2 (step S71). The call response is notified to the call control unit 25 via the key telephone corresponding unit 27 (step S72).

  In response to the call response from the key telephone 6, the call control unit 25 sends a message as a response to the IP conversion correspondence unit 24 to perform processing for communication between the IP telephone 4 and the private branch exchange 2 via the VoIP correspondence board 29. It transmits as a call request response (step S73).

  The communication protocol processing unit 23 that has received the call request response via the IP conversion support unit 24 (step S74) acquires the RTP reception capability of the VoIP compatible board 29 from the recording unit 26 (steps S75 and S76). The communication protocol processing unit 23 generates a message including the acquired RTP reception capability in the call request response, and transmits the message to the IP telephone 4 via the LAN interface unit 22 (step S77).

  Upon receiving this, the IP telephone 4 connects a voice path to the private branch exchange 2 via the VoIP compatible board 29 based on the RTP reception capability included in the call request response. The call control unit 25 establishes a call by connecting the call response received in step S72 and the voice path (step S78).

  Next, the operation in the case where the extension telephone of the call destination is an IP telephone will be described with reference to FIG.

  Steps S81 to S84 are the same as steps S61 to S64, respectively. The call control unit 25 that has received the call request in step S84 determines that the destination dial is the telephone number of the IP telephone 5 that is an extension telephone (steps S85 to S88) through dial analysis processing.

  In this case, the call control unit 25 sends a call request addressed to the IP telephone 5 to the IP conversion support unit 24 (step S89). At that time, the call control unit 25 sends a request for performing RTP peer-to-peer between the IP telephone 4 that is the call source and the IP telephone 5 that is the call destination, and sends out the request. Hereinafter, a request for performing this RTP peer-to-peer is referred to as a peer-to-peer request.

  When the communication protocol processing unit 23 receives this message via the IP conversion correspondence unit 24 (step S90) and determines the peer-to-peer request included in the call request, the IP telephone stored in the storage unit 26 in step S82 4 is acquired (steps S91 and S92), and this information is included in the call control message transmitted to the IP telephone 5 and transmitted to the IP telephone 5 (step S93).

  The IP telephone 5 that has received the call control message of the call request from the IP telephone 4 acquires that the RTP transmission destination is addressed to the IP telephone 4 and information about the RTP reception capability of the IP telephone 4. Become. Based on the acquired information, the IP telephone 5 selects an RTP codec used for transmission, and acquires a destination IP address and port number. Based on these pieces of information, the IP telephone 5 performs RTP transmission suitable for the RTP reception capability of the IP telephone 4.

  If the IP telephone 5 is capable of RTP transmission, the IP telephone 5 transmits a call request response message indicating an acknowledgment to the private branch exchange 2 (step S94). At this time, the IP telephone 5 relates to its own RTP reception capability. The information is included in the call request response message and transmitted.

  When the private branch exchange 2 receives the call request response message via the LAN interface unit 22, the communication protocol processing unit 23 extracts the RTP reception capability and the IP address of the IP telephone 5 from the call request response message, Processing to be stored in the storage unit 26 is performed (step S95). Further, the call request response message is notified to the call control unit 25 via the IP conversion correspondence unit 24 (steps S95 to S97).

  When the response to the call request from the IP telephone 5 is recognized by the reception of the call request response message, the call control unit 25 includes a call request including a message for instructing the IP telephone 4 to make RTP peer-to-peer. A response is generated and transmitted to the IP conversion support unit 24 and the communication protocol processing unit 23 (steps S102 and S103).

  Upon receiving this call request response message, the communication protocol processing unit 23 acquires the RTP reception capability and IP address of the IP telephone 5 from the storage unit 26 (steps S104 and S105). As described with reference to FIG. 3, the IP telephones 4 and 5 are registered in advance as extension terminals of the private branch exchange 2, and the extension telephone numbers of the IP telephones 4 and 5 and the terminal type are IP telephones. Are stored in the storage unit 26 in association with each other. Based on this association and the messages received from the calling side terminal and the called side terminal in steps S81 and S94, the call control unit 25 determines the terminal type. Here, both the calling side terminal and the called side terminal are IP telephones. At this time, the communication protocol processing unit 23 transmits the call request message included in the call request response addressed to the IP telephone 4 (step S106).

  The IP telephone 4 that has received the positive response from the private branch exchange 2 acquires the RTP reception capability and IP address of the IP telephone 5 that is the RTP transmission destination from the call control message, transmits RTP to the IP telephone 5, and sends the IP telephone 4 to the IP telephone 4. A call is established on a peer-to-peer basis (step S107). As described above, RTP can be transmitted and received between the IP telephone 4 and the IP telephone 5 by peer-to-peer without going through the private branch exchange 2.

  According to the present embodiment, an IP telephone as an extension telephone is discriminated, and RTP reception processing and transmission destination are switched from the private branch exchange to the IP telephone in accordance with the RTP reception capability. For this reason, according to the present embodiment, it is possible to reduce the resources of the VoIP-compatible board necessary for extension calls between IP telephones. If all the extension IP telephones have RTP reception capability, the private branch exchange need not have a VoIP compatible board. In either case, as in the first embodiment, the call state of the extension IP telephone can be managed by the private branch exchange.

  The present invention has been described based on the embodiments. However, the present invention is not limited thereto, and it is needless to say that modifications and improvements can be made within the ordinary knowledge of those skilled in the art.

  For example, in the second embodiment, a setting for determining whether or not to perform RTP transmission / reception between peer-to-peer IP phones in advance may be provided and stored in the storage unit 26. In step S86 described above, the call control unit 25 acquires the terminal type from the storage unit 26, but when the setting for not performing RTP transmission / reception is stored in the storage unit 26, this setting is also acquired from the storage unit 26 at the same time. In response to this setting acquisition, the call control unit 25 transmits a call request including an instruction not to perform peer-to-peer communication to the IP conversion corresponding unit 24 in step S89.

  Further, although the second embodiment has been described based on a normal call operation, the present embodiment is not limited to this, and may be applied to a hold or transfer operation. For example, in the transfer operation, the call control unit 25 determines the type of the transfer destination terminal and the like, and when the transfer destination terminal is an IP telephone, the RTP transmission / reception is performed peer-to-peer between the calling terminal and the transfer destination terminal. A message to the effect is sent to the calling terminal and the transfer destination terminal. On the other hand, when the transfer destination terminal is a key telephone, the call control unit 25 sends a message for switching to communication via the VoIP compatible board 29 to the calling terminal and the transfer destination terminal.

  Furthermore, in the second embodiment, it is assumed that the IP telephone 5 can accept the RTP reception capability from the IP telephone 4 and returns a positive response in step S94, but conversely, the IP telephone 5 May not be able to accept the RTP reception capability from the IP telephone 4, and a negative response may be returned. In this case, the following operation can be considered.

  Upon receiving the negative response, the call control unit 25 transmits a call request including the RTP reception capability and the IP address of the VoIP compatible board 29 to the IP telephone 5, and sends the call from the IP telephone 4 to the IP telephone 5 in the storage unit 26. The fact that the call is via the VoIP compatible board 29 is stored. When this request is accepted by the IP telephone 5 and an affirmative response is returned to the private branch exchange 2, the call control unit 25 refers to the storage unit 26 and is an affirmative response for starting communication via the VoIP compatible board 29. And an acknowledgment message including the RTP reception capability and IP address of the VoIP compatible board 29 is transmitted to the IP telephone 4.

  In this way, the RTP transmission / reception path may be dynamically switched from the peer-to-peer RTP transmission / reception between the IP telephones scheduled in the step S93 to the RTP transmission / reception via the private branch exchange 2.

  Further, when performing call control between extension IP telephones, in the first embodiment, a call is always established via the VoIP compatible board 29 as shown in FIG. 5, while in the second embodiment, the call is always peer-to-peer as shown in FIG. However, both call controls may be executed by the same private branch exchange. For example, when the terminal types of the caller terminal and the callee terminal are acquired in step S34 and step S86, the same as in the first embodiment, depending on at least one of the caller and callee IP telephones. The call control unit 25 may determine whether to establish a call via the VoIP-compatible board 29 or to establish a call peer-to-peer as in the second embodiment.

It is a functional block diagram of the key telephone system 1 which is one embodiment of this invention. It is a functional block diagram of the private branch exchange 2 with which the key telephone system 1 is provided. 4 is a flowchart for explaining an operation when registering an IP telephone 4 in the private branch exchange 2 as an extension terminal. 3 is a flowchart for explaining the operation of the private branch exchange 2 when the call destination terminal is a key telephone in the first embodiment. 4 is a flowchart for explaining the operation of the private branch exchange 2 when the call destination terminal is an IP telephone in the first embodiment. 7 is a flowchart for explaining the operation of the private branch exchange 2 when the call destination terminal is a key telephone in the second embodiment. 12 is a flowchart for explaining dial analysis processing according to the second embodiment. 6 is a flowchart for explaining the operation of the private branch exchange 2 when the call destination terminal is an IP telephone in the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Key telephone system 2 Private branch exchange 3 Hub 4, 5 IP telephone 6, 7 Button telephone 21 Main board 22, 31 LAN interface part 23 Communication protocol processing part 24 IP conversion corresponding part 25 Call control part 26 Storage part 27 Button telephone corresponding part 28 Circuit-switched network interface unit 29 VoIP compatible board 30 RTP transceiver unit

Claims (22)

In a call control method performed in a private branch exchange having both a packet line interface and a circuit switched line interface,
The private branch exchange receives a call request from the calling IP phone; and
The private branch exchange determining the type of the called terminal; and
As a result of the determination, when the call destination terminal is a non-IP telephone, a first voice session is established between the private branch exchange and the caller IP telephone via a packet line, while the private branch exchange and the The call source IP is established by establishing a call via a circuit switched line with a call destination non-IP telephone and connecting the voice path by the first voice session and the voice path by the call establishment. Establishing a voice path between a telephone and the called non-IP telephone;
As a result of the determination, when the call destination terminal is an IP telephone, the first voice session is established, while a second voice session via a packet line is established between the private branch exchange and the call destination IP telephone. And connecting the voice path by the first voice session and the voice path by the second voice session to establish a voice path between the caller IP telephone and the callee IP telephone. Establishing a call control method. The call control method according to claim 1, wherein
The private branch exchange includes a storage device for storing a table for managing registration information of both IP telephones and non-IP telephones accommodated as extension terminals,
The call control method, wherein the private branch exchange determines a type of the call destination terminal based on the call request and the table. The call control method according to claim 1, wherein
As a result of the determination, when the call destination terminal is an IP phone, the private branch exchange changes at least part of the content of the call request received from the caller IP phone, and based on the changed call request, A call control method comprising establishing the second voice session peer-to-peer between the private branch exchange and the call destination IP telephone. In a computer program for executing call control processing in a controller of a private branch exchange having both a packet line interface and a circuit switched line interface,
A process of determining a type of a call destination terminal based on a call request received from a call source IP telephone;
As a result of the determination, when the call destination terminal is a non-IP telephone, a first voice session is established between the private branch exchange and the caller IP telephone via a packet line, while the private branch exchange and the The call source IP is established by establishing a call via a circuit switched line with a call destination non-IP telephone and connecting the voice path by the first voice session and the voice path by the call establishment. A process of establishing a voice path between a telephone and the callee non-IP telephone;
As a result of the determination, when the call destination terminal is an IP telephone, the first voice session is established, while a second voice session via a packet line is established between the private branch exchange and the call destination IP telephone. And connecting the voice path by the first voice session and the voice path by the second voice session to establish a voice path between the caller IP telephone and the callee IP telephone. A computer program for causing a computer to execute a process for establishing The computer program according to claim 4, wherein
The private branch exchange includes a storage device for storing a table for managing registration information of both IP telephones and non-IP telephones accommodated as extension terminals,
A computer program that causes the control device to execute a type determination of the call destination terminal based on the call request and the table. The computer program according to claim 4, wherein
As a result of the determination, when the call destination terminal is an IP phone, the private branch exchange changes at least part of the content of the call request received from the caller IP phone, and based on the changed call request, A computer program causing a peer-to-peer to execute a process of establishing the second voice session between the private branch exchange and the call destination IP telephone.   A private branch exchange comprising a recording medium on which the computer program according to any one of claims 4 to 6 is recorded and performing call control according to the computer program. In private branch exchange,
A packet line interface;
A circuit-switched line interface;
A communication protocol processing unit that transmits and receives a call control message according to a communication protocol of an IP telephone connected via the packet line interface;
An IP conversion support unit that converts a call control message received by the communication protocol processing unit into a signal interpretable by the call control unit and converts a signal received from the call control unit into a call control message according to the communication protocol When,
A codec for encoding and decoding voice received from an IP telephone;
A call control unit for determining a type of a call destination terminal based on a call request received from a call source IP telephone;
The call control unit
As a result of the determination, when the call destination terminal is a non-IP telephone, a first voice session is established between the private branch exchange and the caller IP telephone via a packet line, while the private branch exchange and the The call source IP is established by establishing a call via a circuit switched line with a call destination non-IP telephone and connecting the voice path by the first voice session and the voice path by the call establishment. Establishing a voice path between the telephone and the called non-IP telephone;
As a result of the determination, when the call destination terminal is an IP telephone, the first voice session is established, while a second voice session via a packet line is established between the private branch exchange and the call destination IP telephone. And connecting the voice path by the first voice session and the voice path by the second voice session to establish a voice path between the caller IP telephone and the callee IP telephone. A private branch exchange characterized by establishing The private branch exchange according to claim 8,
A storage device for storing a table for managing registration information of both IP telephones and non-IP telephones accommodated as extension terminals;
The private branch exchange is characterized in that the call control unit determines the type of the call destination terminal based on the call request and the table. The private branch exchange according to claim 8,
As a result of the determination, when the call destination terminal is an IP phone, at least part of the content of the call request received from the call source IP phone is changed, and the call destination IP is changed based on the changed call request. A private branch exchange which establishes the second voice session with a telephone in a peer-to-peer manner. In a call control method performed in a private branch exchange having both a packet line interface and a circuit switched line interface,
The private branch exchange receives a call request from the calling IP phone; and
The private branch exchange determining the type of the called terminal; and
As a result of the determination, when the call destination terminal is a non-IP telephone, a first voice session is established between the private branch exchange and the caller IP telephone via a packet line, while the private branch exchange and the The call source IP is established by establishing a call via a circuit switched line with a call destination non-IP telephone and connecting the voice path by the first voice session and the voice path by the call establishment. Establishing a voice path between a telephone and the called non-IP telephone;
As a result of the determination, if the call destination terminal is an IP phone, a third voice session via a packet line is established between the call source IP phone and the call destination IP phone in a peer-to-peer manner, A call control method comprising: establishing a voice path between a caller IP telephone and the callee non-IP telephone. 12. The call control method according to claim 11, wherein establishment of the third voice session is performed.
The caller IP telephone transmitting a first message notifying a call request to the private branch exchange;
In response to the first message, the calling party IP which is notified from the private branch exchange to the calling destination IP telephone at the same time as the first message or stored in the storage device of the private branch exchange in advance Transmitting a second message to notify the RTP (Real-time Transport Protocol) reception capability of the telephone and a call request;
In response to the second message, sending a third message for notifying the call request to the private branch exchange from the call destination IP telephone;
In response to the third message, the private branch exchange notifies the calling IP phone of the calling IP phone simultaneously with the third message or stored in the storage device in advance. Transmitting a fourth message notifying the reception capability, the IP address of the caller IP telephone, and the call request response;
A call control method comprising: establishing a voice path by performing peer-to-peer RTP communication between the caller IP telephone and the callee IP telephone in response to the fourth message. . The call control method according to claim 11, wherein
The private branch exchange includes a storage device for storing a table for managing registration information of both IP telephones and non-IP telephones accommodated as extension terminals,
The call control method, wherein the private branch exchange determines a type of the call destination terminal based on the call request and the table. In a computer program for executing call control processing in a controller of a private branch exchange having both a packet line interface and a circuit switched line interface,
A process of determining a type of a call destination terminal based on a call request received from a call source IP telephone;
As a result of the determination, when the call destination terminal is a non-IP telephone, a first voice session is established between the private branch exchange and the caller IP telephone via a packet line, while the private branch exchange and the The call source IP is established by establishing a call via a circuit switched line with a call destination non-IP telephone and connecting the voice path by the first voice session and the voice path by the call establishment. A process of establishing a voice path between a telephone and the callee non-IP telephone;
As a result of the determination, when the call destination terminal is an IP phone, a packet line is passed between either the call source IP phone or the call destination IP phone with the other IP phone. A computer program for causing a computer to execute processing for requesting to establish a peer-to-peer third voice session. 15. The computer program according to claim 14, wherein the process for requesting establishment of the third voice session comprises:
Receiving a first message notifying a call request from the caller IP telephone;
RTP (Real-time Transport Protocol) reception capability of the caller IP telephone notified at the same time as the first message or previously stored in the storage device of the private branch exchange, and a call request is notified. A process of transmitting the message of 2 to the call destination IP telephone in response to the first message;
A process of receiving a third message notifying the affirmation of the call request transmitted by the call destination IP telephone in response to the second message;
The RTP reception capability of the caller IP phone, the IP address of the caller IP phone, and the call request response that are notified at the same time as the third message or stored in the storage device in advance are notified. 4. A computer program for causing a computer to execute a process of transmitting message 4 to the caller IP telephone in response to the third message. The computer program according to claim 14, wherein
The private branch exchange includes a storage device for storing a table for managing registration information of both IP telephones and non-IP telephones accommodated as extension terminals,
A computer program that causes the control device to execute a type determination of the call destination terminal based on the call request and the table.   A private branch exchange comprising a recording medium on which the computer program according to any one of claims 14 to 16 is recorded, and performing call control according to the computer program. In private branch exchange,
A packet line interface;
A circuit-switched line interface;
A communication protocol processing unit that transmits and receives a call control message according to a communication protocol of an IP telephone connected via the packet line interface;
An IP conversion support unit that converts a call control message received by the communication protocol processing unit into a signal interpretable by the call control unit and converts a signal received from the call control unit into a call control message according to the communication protocol When,
A codec for encoding and decoding voice received from an IP telephone;
A call control unit for determining a type of a call destination terminal based on a call request received from a call source IP telephone;
The call control unit
As a result of the determination, when the call destination terminal is a non-IP telephone, a first voice session is established between the private branch exchange and the caller IP telephone via a packet line, while the private branch exchange and the The call source IP is established by establishing a call via a circuit switched line with a call destination non-IP telephone and connecting the voice path by the first voice session and the voice path by the call establishment. Establishing a voice path between the telephone and the called non-IP telephone;
As a result of the determination, if the call destination terminal is an IP phone, a third voice session via a packet line is established between the call source IP phone and the call destination IP phone in a peer-to-peer manner, A private branch exchange which establishes a voice path between a caller IP telephone and the callee non-IP telephone. The private branch exchange according to claim 18,
Receiving a first message notifying a call request from the caller IP telephone;
RTP (Real-time Transport Protocol) reception capability of the caller IP telephone notified at the same time as the first message or previously stored in the storage device of the private branch exchange, and a call request is notified. 2 message is sent to the callee IP phone in response to the first message;
The third message transmitted from the call destination IP telephone in response to the second message and notifying the affirmation of the call request is received and notified at the same time as the third message or stored in the storage device in advance. A stored fourth RTP reception capability of the caller IP telephone, an IP address of the caller IP telephone, and a fourth message for notifying a call request response are sent in response to the third message. A private branch exchange that transmits to a former IP telephone. The private branch exchange according to claim 18,
A storage device for storing a table for managing registration information of both IP telephones and non-IP telephones accommodated as extension terminals;
The private branch exchange is characterized in that the call control unit determines the type of the call destination terminal based on the call request and the table. In a computer program executed by a processing device of an IP phone,
Prior to notifying the call request to the other IP telephone or simultaneously with the notification, a process of notifying the private branch exchange of the RTP reception capability of the IP telephone;
A process of receiving a call request response from the other IP telephone via the private branch exchange in response to the call request;
In response to the call request response, the RTP reception capability of the other IP telephone set that was notified at the same time as the call request response or stored in the storage device of the private branch exchange prior to the call request response, and the A computer program that causes the processing device to execute a process for establishing a peer-to-peer voice session between the IP telephone and the other IP telephone based on the IP address of the other IP telephone.   An IP telephone comprising a computer-readable recording medium recording the computer program according to claim 21 and the processing device.

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