JP2005252809A - Premise system for ip phone and speech transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a premise system for IP phone capable of transferring a speech to thereby relive the cost burden on users without the need for the installation of a SIP server and a gatekeeper. <P>SOLUTION: The premise system for IP phone utilizes a combination among mutual communication between a plurality of IP phones 30 and a gateway router 20, IP phone communication functions of the IP phones 30, and a NAT traversal function of the gateway router 20 to attain transfer of speeches and to dispense with the installation of the SIP server and the gatekeeper. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an IP telephone premises system constructed in the premises or home of a subscriber who receives an IP telephone service, and a call transfer method used in the IP telephone premises system, in particular, without installing a SIP server or a gatekeeper. The present invention relates to an IP telephone premises system and a call transfer method that enable transfer of a call.

  2. Description of the Related Art An IP telephone local area system is known that includes a LAN connected to a plurality of IP telephones, and a gateway that connects the LAN to a WAN that provides IP telephone services. It has been.

  In this type of local system, in order to share one or a plurality of global addresses with a plurality of IP telephones, at least a call transfer for transferring a call between an external IP telephone and a local IP telephone to another IP telephone in the local area. A function is required, and further, a call hold function for holding a call between an external IP telephone and a local IP telephone, an extension call function for performing a call between the local IP telephones, and the like are also required.

In the IP telephone premises system, the above functions can be realized by a SIP server compliant with SIP (Session Initiation Protocol), H.264, or the like. There are known gatekeepers conforming to H.323 or IP-PBX (private branch exchange) having these functions (for example, see Patent Documents 1 and 2).
JP 2002-325097 A JP 2003-032372 A

  However, if a SIP server, gatekeeper, or IP-PBX having these functions is installed in the IP telephone premises system, the equipment cost, installation work cost, maintenance cost, etc. are generated, so the burden on the user increases. There was a problem to do.

  The present invention has been considered in view of the above circumstances, and it is possible to transfer a call without installing a SIP server or a gatekeeper, and to reduce the cost burden on the user and a call transfer system for the IP telephone. The purpose is to provide a method.

  In order to achieve the above object, an IP telephone premises system according to the present invention is an IP telephone premises system constructed in a premises or a premises of a subscriber who receives an IP telephone service, wherein the premises or in-home LAN is connected to the premises system. A gateway router that connects to a WAN that provides an IP telephone service; and a plurality of IP telephones that are connected to the LAN. The gateway router assigns a private address that is valid in the LAN to the plurality of IP telephones. Notification from the IP telephone using a DHCP server function unit to be allocated, a NAT function unit that mutually translates a global address and a private address that are valid in the WAN using a NAT table, and a private communication protocol The NAT table is associated with the private address. And a NAT traversal function unit that switches a communication path in the LAN by changing the NAT table, and the plurality of IP telephones are configured as a DHCP server function of the gateway router. A DHCP client function unit for acquiring the private address by using the local area communication protocol, an extension number notification function unit for notifying extension number information to the gateway router using the local area communication protocol, and an IP provided in the gateway router and / or the IP telephone. An IP telephone communication function unit for communicating with the IP telephone server of the WAN using a telephone communication protocol and enabling a call with an external IP telephone; and a NAT traversal function of the gateway router using the local communication protocol. The external IP phone by controlling Calls and is a structure in which and a call forwarding function unit to be transferred to the IP telephone of the specified extension.

  If comprised in this way, it is based on the combination of the mutual communication between several IP telephones and a gateway router, the IP telephone communication function which an IP telephone has, and the NAT traversal function which a gateway router has using a local area communication protocol. Call transfer is possible. This eliminates the need to install a SIP server or a gatekeeper in the IP telephone premises system, thereby reducing the cost burden on the user.

In the IP telephone local system according to the present invention, as a communication procedure defined by the local communication protocol, the IP telephone serves as a transfer source and a communication procedure for notifying the gateway router of its own extension number information. A communication procedure for the IP telephone to notify the gateway router of the extension number of the IP telephone as a transfer destination; and a communication procedure for the gateway router to inquire the transfer destination of the IP telephone whether transfer is possible A communication procedure for the transfer destination IP phone to notify the gateway router whether transfer is possible, a communication procedure for the gateway router to notify the transfer source IP phone whether transfer is possible, and transfer The original IP telephone requests the gateway router to switch the connection using the NAT traversal function. , A communication procedure is a configuration including.
If comprised in this way, it can transfer a telephone call, after confirming the propriety of transfer using a local communication protocol.

In the IP telephone local system according to the present invention, as a communication procedure defined by the local communication protocol, the IP telephone of the transfer source notifies the IP telephone of the transfer destination of RTP management information of a UDP voice packet. The communication procedure is included.
With this configuration, it is possible to smoothly reproduce the RTP stream in the IP telephone of the transfer destination, and to avoid a decrease in voice quality due to the transfer.

The IP telephone local system according to the present invention includes a communication procedure for the IP telephone in communication with the external IP telephone to request the gateway router to hold a call as a communication procedure defined by the local communication protocol. In addition, the gateway router includes a call hold function unit that transmits a UDP voice packet of a hold sound to the external IP telephone in response to a call hold request.
With this configuration, the call hold function can be realized even in a local system where no SIP server or gatekeeper is installed.

In the IP telephone local area system according to the present invention, as a communication procedure specified by the local area communication protocol, the IP telephone as an extension connection source notifies the gateway router of the extension number of the IP telephone as an extension connection destination. Communication procedure for the gateway router to make an inquiry to the IP telephone of the extension connection destination whether or not the extension connection is possible, and the IP telephone of the extension connection destination notifies the gateway router of the transfer possibility A communication procedure for the gateway router to notify the IP telephone of the extension connection source whether or not the extension connection is possible, and the IP telephone of the extension connection source and the IP telephone of the extension connection destination, The UDP voice packet of the extension call is combined through the gateway router or without the gateway router. It is constituted comprising, a communication procedure for transmitting and receiving the.
With this configuration, an extension call function can be realized even in a local system where no SIP server or gatekeeper is installed.

In the IP telephone local area system of the present invention, the local area communication protocol is a TCP / IP standard protocol or a protocol in which a unique command is added to the TCP / IP standard protocol.
With this configuration, it is possible to easily define the local communication protocol using the TCP / IP standard protocol.

In the IP telephone local area system according to the present invention, the IP telephone communication protocol is SIP or H.264. The protocol conforms to H.323.
With this configuration, SIP or H.264 can be used. The present invention can be applied to a local system that receives an IP telephone service compliant with H.323.

In the IP telephone local area system according to the present invention, the LAN is a wired LAN or a wireless LAN.
With this configuration, the present invention can be applied not only to a private system constructed with a wired LAN but also to a private system constructed with a wireless LAN.

  In order to achieve the above object, a call transfer method according to the present invention includes a LAN constructed in a premises or a home of a subscriber who receives an IP telephone service, and a gateway router that connects the LAN to a WAN that provides the IP telephone service. And a call transfer method in an IP telephone premises system comprising a plurality of IP telephones connected to the LAN, wherein the gateway router allocates a private address effective in the LAN to the plurality of IP telephones. A plurality of IP telephones notify extension information to the gateway router using a local communication protocol, and the gateway router mutually converts a global address valid in the WAN and the private address. Extension number notified from the IP phone in the NAT table of Information is registered in association with the private address, and the IP telephone communicates with the IP telephone server of the WAN using an IP telephone communication protocol provided in the gateway router and / or the IP telephone, and an external IP telephone The IP telephone that is on the call controls the NAT traversal function of the gateway router by using the local area communication protocol, so that the call with the external IP telephone is made with the designated extension number. This is a method of transferring to an IP telephone.

  If this method is used, it is possible to transfer a call without installing a SIP server or gatekeeper, so that the equipment cost, installation work cost, maintenance cost, etc. of the SIP server or gatekeeper are not required, and the user bears the expense. Can be reduced.

Further, in the call transfer method of the present invention, the IP telephone as the transfer source notifies the gateway router of the extension number of the IP telephone as the transfer destination, and the gateway router determines whether transfer is possible or not. An inquiry is made to the IP telephone, the IP telephone of the transfer destination notifies the gateway router of whether transfer is possible, and the gateway router notifies the transfer source of the IP telephone of transfer possibility, and when the transfer is possible, the transfer is performed. There is a method in which the original IP telephone requests the gateway router to switch the connection by the NAT traversal function.
According to such a method, when a call is transferred, it is possible to confirm in advance whether or not the transfer can be made to the transfer destination IP telephone using a local communication protocol.

  As described above, according to the present invention, mutual communication between a plurality of IP telephones and a gateway router, an IP telephone communication function possessed by an IP telephone, and a NAT traversal function possessed by a gateway router, using a local area communication protocol. The call transfer function can be realized without using a SIP server or gatekeeper by combining with, so the equipment cost, installation work cost, maintenance cost, etc. of the SIP server and gatekeeper are not required, and the user bears the cost. Can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an IP telephone local area system according to an embodiment of the present invention.
As shown in this figure, the IP telephone premises system 1 is constructed in the premises or in the premises of the subscriber who receives the IP telephone service. The LAN (local network) 10 constructed in the premises or in the house, and the IP It comprises a gateway router 20 that connects the LAN 10 to a WAN (Wide Area Network) 2 that provides telephone services, and a plurality of IP telephones 30 that are connected to the LAN 10.

The WAN 2 is provided with an IP telephone server 3 (for example, a SIP server) that stores the telephone number of the service subscriber and the WAN-side IP address (global address) and relays the connection between the IP telephones. The local IP telephone 30 can communicate with the external IP telephone 4 connected to the WAN 2 by communicating with the IP telephone server 3 using the IP telephone communication protocol provided in the gateway router 20 or the IP telephone 30.
There is no particular limitation on the IP telephone communication protocol to be used. For example, SIP, H.264, etc. A protocol conforming to H.323 can be used.

  There are no restrictions on the LAN 10 standard, and various standards including a wired LAN and a wireless LAN can be used. For example, if a wireless LAN access point is connected to the LAN port of the gateway router 20 and a wireless LAN adapter is connected to the LAN port of the IP telephone 30, the IP telephone premises system 1 can be constructed wirelessly. .

FIG. 2 is a block diagram of the gateway router according to the embodiment of the present invention.
As shown in this figure, the gateway router 20 includes a WAN interface 21 connected to the WAN 2, a LAN interface 22 connected to the LAN 10, a storage unit 23 for storing data such as programs and NAT tables, and a gateway router. The control part 24 which controls 20 operation | movement is provided.

  The control unit 24 has a DHCP (Dynamic Host Configuration Protocol) server function unit 24a that assigns a valid LAN-side IP address (private address) in the LAN 10 to the plurality of IP telephones 30 as a functional configuration realized by a program. , NAT function unit 24b that mutually converts a WAN side IP address and a LAN side IP address using a NAT (Network Address Translator) table, and extension number information notified from IP telephone 30 using a local communication protocol Are registered in the NAT table in association with the LAN side IP address, and a NAT traversal function unit that switches the communication path in the LAN 10 by changing the NAT table. 24d and a call hold function unit 24e that generates a UDP (User Datagram Protocol) voice packet of a hold tone in response to a call hold request from the IP phone 30 during a call and transmits the packet to the external IP phone 4 ing.

FIG. 3 is a configuration diagram of a NAT table used by the gateway router according to the embodiment of the present invention.
The NAT table 40 shown in this figure is an IP generated in the gateway router 20 by the DHCP server function and extension number registration function of the gateway router 20 and the DHCP client function and extension number notification function of each IP telephone 30 when the system is started. It is a header replacement table.

The NAT function unit 24b of the gateway router 20 discriminates the external IP telephone 4 on the WAN2 side by the WAN side IP address 41 and the port number 42, and determines the LAN side IP telephone 30 as the LAN side IP address 43, the MAC address 44, and the extension. By discriminating with the number 45 and managing the connection relationship with the NAT table 40, it is possible to distribute the IP packet data.
Then, the NAT traversal function unit 24 d switches the connection partner by changing the correspondence between the WAN side IP address 41 and the LAN side IP address 43 in the NAT table 40.

FIG. 4 is a configuration diagram of UDP voice packet data used in the embodiment of the present invention.
The UDP voice packet data 50 is used for carrying call data in IP telephone communication. The UDP voice packet data 50 is described in the UDP header 51, and is used for the WAN function IP address and port number 52, and a predetermined number of bytes. The front PCM audio data 53 and the rear PCM audio data 54 are provided.
The IP telephone 30 ensures good speech quality by managing the UDP voice packet data 50 using RTP (Real Time Protocol).

  When the NAT function unit 24b of the gateway router 20 performs packet transmission from the LAN 10 side to the WAN 2 side, the LAN side IP address of the UDP voice packet data 50 received from the LAN 10 side based on the information registered in the NAT table is used as the WAN side. When the packet is received from the WAN 2 side after being converted into the IP address + port number, the WAN side IP address + port number of the UDP voice packet data 50 is converted into the LAN side IP address.

FIG. 5 is a block diagram of the IP telephone according to the embodiment of the present invention.
As shown in this figure, the IP telephone 30 includes a LAN interface 31 connected to the LAN 10, a speaker 32 and a microphone 33 used for a call, an operation unit 34 including a plurality of button switches, and a notification for outputting a ring tone. A unit 35, a storage unit 36 for storing programs and data, and a control unit 37 for controlling the IP telephone 30 are provided.

  As a functional configuration realized by a program, the control unit 37 uses a DHCP client function unit 37a that obtains a LAN-side IP address by the DHCP server function of the gateway router 20 and an extension number to the gateway router 20 using a local communication protocol. An extension number notification function unit 37b for notifying information, an IP telephone communication function unit 37c that communicates with the IP telephone server 3 of the WAN 2 using the IP telephone communication protocol and enables a call with the external IP telephone 4, A call transfer function unit 37d for transferring a call with the external IP telephone 4 to the IP telephone 30 of the designated extension number by controlling the NAT traversal function of the gateway router 20 using a communication protocol. .

  The local communication protocol defines a communication procedure (for example, a command) between the gateway router 20 and the IP telephone 30. For example, a TCP / IP standard protocol such as UPnP (Universal Plug & Play) or telnet, or a TCP / IP standard A protocol with its own command added is used.

  The basic communication procedure prescribed by the private communication protocol includes a communication procedure for the IP telephone 30 to notify the gateway router 20 of its own extension number information. The communication procedure for the original IP telephone 30 to notify the gateway router 20 of the extension number of the IP telephone 30 to be transferred, and the gateway router 20 to inquire of the transfer destination IP telephone 30 whether transfer is possible or not. A communication procedure, a communication procedure for the transfer destination IP telephone 30 to notify the gateway router 20 of whether transfer is possible, and a communication procedure for the gateway router 20 to notify the transfer source IP telephone 30 of transfer possibility Then, the IP phone 30 as the transfer source switches the connection by the NAT traversal function to the gateway router 2. A communication procedure for requesting the transfer source of the IP telephone 30, and a communication procedure for notifying the RTP management information UDP voice packets to the destination IP telephone 30.

The communication procedure related to the call hold function includes a communication procedure for the IP telephone 30 in communication with the external IP telephone 4 to request the gateway router 20 to hold the call, and further, the communication procedure related to the extension call function is as follows. The communication procedure for the IP telephone 30 as the extension connection source to notify the gateway router 20 of the extension number of the IP telephone 30 as the extension connection destination, and the IP address of the extension connection destination as to whether or not the gateway router 20 allows the extension connection. A communication procedure for inquiring the telephone 30, a communication procedure for the extension destination IP telephone 30 to notify the gateway router 20 of whether or not extension connection is possible, and the gateway router 20 determines whether or not extension connection is possible Communication procedure for notifying the IP phone 30, the extension connection source IP phone 30 and the extension connection destination IP phone 3 There is through a gateway router 20, or, without passing through the gateway router 20, and a communication procedure for transmitting and receiving UDP voice packets extension call each other.
Note that these communication procedures are main communication procedures necessary for realizing the call transfer function, the call hold function, and the extension call function, and it goes without saying that other communication procedures can be arbitrarily added in the implementation. .

FIG. 6 is a sequence diagram of the call transfer operation according to the embodiment of the present invention, and FIG. 7 is a flowchart of the call transfer operation according to the embodiment of the present invention.
FIG. 6 is performed between the transfer source IP phone 30, the gateway router 20, and the transfer destination IP phone 30 when a call is transferred from the transfer source IP phone 30 to the transfer destination IP phone 30. The sequence of command communication is shown, and is executed sequentially from C101 in numerical order. In addition, an operation flow of the entire IP telephone premises system 1 during call transfer is shown.

  Commands transmitted by the transfer source IP telephone 30 include an extension call request C101 and a switch switching request C107 transmitted to the gateway router 20, and a transfer request C105 transmitted to the transfer destination IP telephone 30. 20 includes a status confirmation C102 transmitted to the transfer destination IP telephone 30 and a status notification C104 transmitted to the transfer source IP telephone 30, and the transfer destination IP telephone 30 transmits the command. As commands to be transmitted, there are a status notification C103 transmitted to the gateway router 20 and a transfer permission / transfer rejection C106 transmitted to the IP telephone 30 as a transfer source.

  Each of the above commands C101 to C107 includes the status of the request / confirmation / response and the meaning of the instruction, and at the same time, the telephone side control such as WAN IP address information of UDP voice packet data, extension number, and ringing tone designation. You can add information.

Next, the operation at the time of call transfer in the IP telephone local system 1 will be described with reference to FIG. 6 and FIG.
At the time of start-up, the IP telephone local system 1 assigns a LAN side IP address to each IP telephone 30 by the DHCP server function of the gateway router 20, and then each IP telephone 30 uses an internal communication protocol to extend the extension number. To the gateway router 20, the extension number and the LAN side IP address are registered in association with the NAT table of the gateway router 20.

  After completion of the start-up processing, when the extension number of the IP telephone 30 that is the transfer destination is dialed in the IP telephone 30 that is in a communication state with the external IP telephone 4 on the WAN 2 side (S201), the extension number of the transfer source IP telephone 30 and The extension call request C101 including the extension number of the transfer destination IP telephone 30 is transmitted from the transfer source IP telephone 30 to the gateway router 20 (S202).

Upon receiving the extension call request C101, the gateway router 20 temporarily stores the extension number in a predetermined memory area, and sends a status confirmation C102 to the transfer destination IP phone 30 in order to check whether or not the transfer of the transfer destination IP phone 30 is possible. Send. Receiving this, the forwarding IP phone 30 returns information as to whether or not a call is possible to the gateway router 20 as a status notification C103.
The gateway router 20 that has received the status notification C103 returns a status notification C104 of the transfer destination IP phone 30 to the transfer source IP phone 30. Thereby, the transfer source IP telephone 30 can know the state of the transfer destination IP telephone 30.

  When the transfer source IP phone 30 confirms the state of the transfer destination IP phone 30 and determines that call transfer is possible, the transfer source IP phone 30 transmits a transfer request C105 including the WAN side IP address of the call partner to the transfer destination IP phone 30. (S203). The transfer destination IP telephone 30 returns a transfer permission C106 to the transfer source IP telephone 30 if transfer is possible and a transfer rejection C106 if transfer is impossible (S204). In the case of transfer permission, the WAN side IP address is held, and the WAN side IP address of the other party is inserted into the UDP voice packet transmitted / received to / from the gateway router 20 so that the UDP voice packet is connected to the WAN 2 side. Prepare to send and receive.

  When the transfer source IP telephone 30 receives the transfer permission C106, it transmits a switch switching request C107 by the NAT traversal function to the gateway router 20. Upon receiving this, the gateway router 20 reads the extension number temporarily stored in the predetermined memory area, and changes the correspondence between the WAN side IP address (port number) and the LAN side IP address in the NAT table. Thereby, a UDP voice packet stream is formed between the external IP telephone 4 and the transfer destination IP telephone 30, and the call transfer is completed (S205). Further, the data in the NAT table is deleted by the end of the transfer destination IP telephone 30 (S206).

Moreover, in the IP telephone local area system 1 of the present embodiment, call holding can be performed according to the following procedure.
When a hold operation is performed on the IP telephone 30 during a call, a call hold request is transmitted from the IP telephone 30 to the gateway router 20. Receiving this, the gateway router 20 generates a UDP voice packet of holding tone and sends it to the external IP telephone 4 of the other party. Thereby, the call with the external IP telephone 4 is put on hold. The held call can be transferred to any IP telephone 30 using the above-described call transfer function.

Further, in the IP telephone on-site system 1 according to the present embodiment, an extension call can be performed by the following procedure.
The IP telephone 30 serving as the extension connection source notifies the gateway router 20 of the extension number of the IP telephone 30 serving as the extension connection destination. Receiving this, the gateway router 20 inquires of the extension-connected IP telephone 30 whether the extension connection is possible, and waits for a reply from the extension-connected IP telephone 30. When the extension-connected IP telephone 30 notifies the gateway router 20 of whether transfer is possible, this is notified to the extension-connected IP telephone 30 via the gateway router 20. This notification includes at least the LAN-side IP address of the extension connection destination. When extension connection is permitted, the extension connection source IP telephone 30 establishes an extension communication path that passes through the gateway router 20 or an extension communication path that does not pass through the gateway router 20, and is connected to the extension connection destination IP telephone 30. UDP voice packets are transmitted to and received from each other. As a result, the IP telephone 30 in the IP telephone premises system 1 can make an extension call.

  The present invention is applied to the IP telephone premises system constructed in the premises or home of the subscriber who receives the IP telephone service, and the call transfer method used in the IP telephone premises system. In particular, the IP telephone premises system according to the present invention can transfer a call without installing a SIP server or a gatekeeper, and thus is suitable for an application where it is desired to construct an IP telephone premises system at a low cost.

It is a block diagram which shows the local system for IP telephones concerning embodiment of this invention. It is a block diagram of the gateway router which concerns on embodiment of this invention. It is a block diagram of a NAT table used by a gateway router according to an embodiment of the present invention. It is a block diagram of UDP voice packet data used in the embodiment of the present invention. 1 is a block diagram of an IP telephone according to an embodiment of the present invention. It is a sequence diagram of a call transfer operation according to an embodiment of the present invention. It is a flowchart figure of the call transfer operation | movement which concerns on embodiment of this invention.

Explanation of symbols

1 IP phone premises system 2 WAN
3 IP phone server 4 External IP phone 10 LAN
20 Gateway router 30 IP phone 40 NAT table 50 UDP voice packet data

Claims (10)

An IP phone premises system constructed on the premises or in the premises of a subscriber who receives an IP phone service,
A gateway router that connects the local area network or the home LAN to the WAN that provides the IP telephone service;
A plurality of IP telephones connected to the LAN;
Including
The gateway router is
A DHCP server function unit for allocating a private address effective in the LAN to the plurality of IP telephones;
Using a NAT table, a NAT function unit that mutually converts a global address valid in the WAN and the private address;
An extension number registration function unit for registering extension number information notified from the IP telephone in the NAT table in association with the private address, using a local communication protocol;
A NAT traversal function unit for switching a communication path in the LAN by changing the NAT table;
With
The plurality of IP telephones are
A DHCP client function unit for acquiring the private address by a DHCP server function of the gateway router;
An extension number notification function unit for notifying extension number information to the gateway router using the local communication protocol;
An IP telephone communication function unit that communicates with the IP telephone server of the WAN using the IP telephone communication protocol included in the gateway router and / or the IP telephone, and enables a call with an external IP telephone;
A call transfer function unit for transferring a call with the external IP phone to the IP phone with a designated extension number by controlling a NAT traversal function of the gateway router using the local communication protocol;
An IP telephone premises system characterized by comprising: As a communication procedure defined by the on-site communication protocol,
A communication procedure for the IP telephone to notify the gateway router of its extension number information;
A communication procedure for the IP telephone as the transfer source to notify the gateway router of the extension number of the IP telephone as the transfer destination;
A communication procedure for the gateway router to inquire the transfer destination IP phone whether transfer is possible;
A communication procedure for the IP telephone of the transfer destination to notify the gateway router whether transfer is possible;
A communication procedure for the gateway router to notify the IP telephone of the transfer source whether transfer is possible;
A communication procedure for the IP telephone of the transfer source to request the gateway router to switch the connection by the NAT traversal function;
The IP telephone premises system according to claim 1, comprising: As a communication procedure defined by the on-site communication protocol,
3. The IP telephone premises system according to claim 1 or 2, further comprising a communication procedure for the transfer source IP telephone to notify the transfer destination IP telephone of RTP management information of a UDP voice packet. As a communication procedure defined by the on-site communication protocol,
The IP telephone in a call with the external IP telephone includes a communication procedure for requesting the gateway router to hold a call;
The gateway router is
The IP telephone premises system according to any one of claims 1 to 3, further comprising a call hold function unit that transmits a UDP voice packet of a hold sound to the external IP telephone in response to a call hold request. As a communication procedure defined by the on-site communication protocol,
A communication procedure for the IP telephone serving as an extension connection source to notify the gateway router of the extension number of the IP telephone serving as an extension connection destination;
A communication procedure for the gateway router to inquire of the IP telephone of the extension connection destination whether or not extension connection is possible;
A communication procedure for the IP telephone of the extension connection destination to notify the gateway router of whether transfer is possible;
A communication procedure for the gateway router to notify the IP telephone of the extension connection source whether or not extension connection is possible;
A communication procedure for transmitting / receiving UDP voice packets of extension calls to / from each other between the IP telephone of the extension connection source and the IP telephone of the extension connection destination via the gateway router or without the gateway router; ,
The IP telephone premises system according to any one of claims 1 to 4, characterized by comprising:   6. The IP telephone premises according to claim 1, wherein the premises communication protocol is a TCP / IP standard protocol or a protocol in which a unique command is added to the TCP / IP standard protocol. system.   The IP telephone communication protocol is SIP or H.264. The IP telephone premises system according to any one of claims 1 to 6, wherein the protocol conforms to H.323.   The IP telephone premises system according to claim 1, wherein the LAN is a wired LAN or a wireless LAN. An IP comprising a LAN constructed in the premises or home of a subscriber who receives an IP telephone service, a gateway router connecting the LAN to a WAN providing the IP telephone service, and a plurality of IP telephones connected to the LAN A call transfer method in a telephone premises system,
The gateway router allocates a valid private address in the LAN to the plurality of IP phones,
The plurality of IP telephones notify extension number information to the gateway router using a private communication protocol,
The gateway router registers the extension number information notified from the IP telephone in association with the private address in the NAT table for mutually converting the global address valid in the WAN and the private address,
The IP telephone communicates with the IP telephone server of the WAN using an IP telephone communication protocol included in the gateway router and / or the IP telephone, and performs a call with an external IP telephone.
The IP telephone in a call transfers the call to the external IP telephone to the IP telephone of a designated extension number by controlling the NAT traversal function of the gateway router using the local area communication protocol. A call transfer method characterized by the above. The IP phone as the transfer source notifies the gateway router of the extension number of the IP phone as the transfer destination,
The gateway router inquires of the IP telephone of the transfer destination whether transfer is possible,
The IP telephone of the transfer destination notifies the gateway router of whether transfer is possible,
The gateway router notifies the IP telephone of the transfer source whether transfer is possible,
10. The call transfer method according to claim 9, wherein, when transfer is possible, the IP telephone set as the transfer source requests the gateway router to switch the connection by the NAT traversal function.

Images