JP2009004974A - Signal control system in ip telephone system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To specify the concrete form of control signals for sending PB signals generated by a mobile phone terminal during communication to a telephone main unit connected through a LAN by outbound signals. <P>SOLUTION: A WLAN-AP 3 is provided between the LAN and the mobile phone terminal through a radio telephone network. When voice packets received from the radio telephone network during the communication are fetched and decoded in a voice packet decoding part 15, in the case where an IB-DTMF detection part 16 detects inbound DTMF signals sent out by the PB signals as the control signals, an OB-DTMF generation part 17 keeps DTMF signals obtained from the inbound DTMF signals as they are, and sends out outbound DTMF signals generated by substituting a destination address to the one for the telephone main unit, to the LAN as the outbound signals. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a system that is simple and easy to control signals between a telephone and a telephone main unit in an IP telephone system provided in an office.

  In recent IP telephone systems for offices, call control messages such as SIP (Session Initiation Protocol) are usually received once by UDP (User Datagram Protocol), and transferred after performing processing such as conversion according to the destination. B2BUA (Back to Back User Agent) method is adopted. For signal transmission between telephones, packet communication using RTP (Real-time Transport Protocol) packets is performed. This communication can reduce the amount of packets by adopting a P2P (Peer to Peer) system that does not involve a main device. The P2P method is a form of Internet use in which computers are connected to each other and directly send and receive information such as files. Therefore, in general, a PB (Push Button) signal generated by a dial operation on a telephone is output to an audio signal line by a DTMF (Dial Tone Multi Frequency) signal by an audible sound. Formed into RTP packets. For this reason, the telephone needs a function for converting an audible signal including voice and an RTP packet, and the RTP packet converted from the audible signal is called a voice packet. When the audio packet is decoded, it is directly converted into an audible signal, that is, an in-band signal (sometimes abbreviated as IB) which is a so-called audio band. That is, the PB signal as an audible signal is converted into an RTP packet, that is, a voice packet by an in-band DTMF signal, and transferred over the network.

  Further, as described in Japanese Patent Laid-Open No. 2003-78958 (Patent Document 1), in addition to this in-band DTMF system, standardization that uses outside the audible frequency band as a dial system sent from a telephone terminal to an exchange device Out-of-band (sometimes abbreviated as OB) signaling. In the out-band signal system, a dial number is encoded and transmitted via a control signal line in a message format. The out-band signaling method in Patent Document 1 is used as a signaling method for transferring from a base station to an exchange device in order to speed up a call setup time when a telephone number is transmitted in a wireless local loop system.

  On the other hand, for example, when a VPN (Virtual Private Network) is formed, the telephone exchange device can directly receive a voice packet based on an in-band DTMF signal as a destination dial number from a calling telephone and control call connection. However, after the call connection is established by the response of the called party, the voice packet is transferred between the telephones via the trunk and does not pass through the telephone exchange device. Nevertheless, since an ordinary in-house telephone exchange has various functions, the telephone exchange apparatus requires a control signal to be exchanged with the telephone even when a telephone call is being made between the telephones. For example, there is a control signal such as a transfer request. When the control signal is generated on the telephone side using a dial pad that generates a PB signal, the control signal may be an in-band DTMF signal or the above-described out-band signal. In the case of an out-band signal, the telephone needs to have the conversion function.

  As a related technique, there is a communication device disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-33664 (Patent Document 2). The outline of this apparatus will be described with reference to FIG. In FIG. 1, a mobile phone terminal 1 is connected to a WLAN-AP (wireless LAN adapter) 3 via a wireless telephone network 2, and the WLAN-AP 3 is connected to a telephone main device 5 which is a telephone exchange device via a LAN 4. .

  In Patent Document 2, the mobile phone terminal 1 is a third generation terminal, the wireless telephone network 2 is a third generation mobile communication network, the WLAN-AP 3 is a third generation gateway, and the telephone main device 5 is equivalent to a content distribution server. is there. The 3rd generation gateway performs code conversion between the 3rd generation mobile communication network and the LAN, has a built-in DTMF detection unit, detects DTMF sound by a push button operation from the 3rd generation terminal, and connects to the LAN. A control signal is generated at the connected content distribution server.

  That is, the WLAN-AP 3 in FIG. 1 receives a DTMF signal transmitted from the mobile phone terminal 1 via the wireless telephone network 2, converts it into a control signal for the telephone main device 5 connected to the LAN 4, and generates the LAN 4 Is being sent to. With such a configuration, according to Patent Document 2, a telephone main device that receives a call connection request from a telephone receives an in-band DTMF signal, identifies the connection destination, and connects the telephones. Calls can be made by sending and receiving packets directly. Therefore, when the WLAN-AP in this state receives an in-band DTMF signal from the telephone via the wireless telephone network, it can generate a control signal matched with the in-band DTMF signal as a control signal in the telephone main unit. The control signal is generated between the wireless telephone network and the LAN by a predetermined encoding method or generated by protocol conversion.

  That is, in the communication apparatus of Patent Document 2, the main purpose is to generate a control signal on the LAN by code conversion or protocol conversion between the wireless telephone network and the LAN. However, Patent Document 2 touches on the “signal form” of the control signal formed between the telephone main device and the telephone when the telephone main device connects the telephone via the network to form the VPN. Absent.

  That is, when generating a control signal such as a transfer request that occurs when a call is in progress between telephones by generating a PB signal using the dial pad of the telephone, specific information regarding the control signal is disclosed It has not been.

JP 2003-79958 A JP 2005-33664 A

  There is an opportunity for a telephone terminal to send a control signal by in-band DTMF to a telephone main apparatus connected via an IP network with a PB signal generated during communication. In this case, since the RTP packet is not delivered to the main apparatus in the P2P communication, as described above, an adapter for monitoring the voice signal being communicated is provided between the IP network and the telephone terminal, and the adapter is in-band. It is necessary to convert the DTMF signal into an out-band signal and send it to the telephone main unit.

  The problem to be solved is that when a PB signal generated at a telephone terminal in communication is sent as a control signal by an out-band signal to a telephone main apparatus connected via an IP network, the specific signal form is specified. That is not.

  The present invention is a telephone system connected to an IP network, and when a PB signal generated at a telephone terminal in communication is sent to the main telephone apparatus connected via the IP network as an out-band signal, the control signal is specified. The purpose is to identify specific forms.

  Therefore, the present invention converts an in-band DTMF signal transmitted as a control signal from a telephone terminal communicating with a telephone system configured with an IP network into a control signal and converts the signal into an out-band signal. The present invention relates to signal control sent to a telephone main unit via a network. The main feature is that the DTMF signal obtained from the in-band DTMF signal is left as it is, and the out-band signal with the destination address replaced is defined as an out-band DTMF signal.

  Specifically, an adapter for receiving a voice signal during communication is provided between the IP network and the telephone terminal, and an in-band DTMF signal transmitted as a PB signal from the telephone terminal during communication is detected as a control signal. In this case, the signal is converted into an out-band signal and transmitted to the IP network. The adapter has means for generating and transmitting the out-band signal to the out-band DTMF signal by replacing the destination address with the DTMF signal obtained from the in-band DTMF signal as it is.

  The signal control method in the IP telephone system of the present invention uses a signal corresponding to DTMF serving as a control signal, that is, a signal defined as an outband DTMF signal, as an outband signal on the IP network. The in-band DTMF signal is a signal obtained by encoding DTMF generated by combining one each of four types of high-frequency sound systems and four types of low-frequency sound systems depending on the sound frequency. The out-band DTMF signal is numerical information corresponding to the in-band DTMF signal or a DTMF signal as a symbol. Further, the destination of the in-band DTMF signal is a telephone terminal, and the destination of the out-band DTMF signal is a telephone main unit.

  Therefore, in the case of miniaturization by simplifying the function as in the case of a telephone terminal, particularly a mobile phone terminal, the control signal can be transmitted by a PB signal only with a dial pad. Furthermore, the telephone main device can set the control signal corresponding to the PB signal even if the control conditions corresponding to DTMF are changed, so that the signal identification and the conversion or change of the control are easy.

  The present invention specifies a form of a control signal for transmitting a PB signal generated by a telephone terminal in communication to an telephone main apparatus connected via an IP network by an out-band signal in a telephone system connected to an IP network. For this purpose, a DTMF-compatible signal, that is, an out-band DTMF signal is used as an out-band signal on the IP network. As a result, a system has been realized in which a control signal is transmitted by a PB dial from a cellular phone terminal which has been reduced in size by simplifying functions, and a signal can be easily identified and converted or changed in the control of the telephone main unit.

  Embodiments will be described below with reference to the drawings. However, the drawings mainly show portions according to the present invention, and some components that are functionally essential are omitted. Moreover, as long as the purpose and function of the present invention are satisfied, the illustrated functional blocks can be freely divided and merged, the procedure can be changed, and the like, and the following description does not limit the present invention.

  A first embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a block diagram illustrating an embodiment of a system according to the present invention. In FIG. 1, a mobile phone terminal 1, a wireless telephone network 2, a WLAN-AP (wireless LAN adapter) 3, a LAN 4, a telephone main device 5, and a fixed telephone terminal 6 are shown.

  The cellular phone terminal 1 is connected to the WLAN-AP 3 via the wireless telephone network 2. The radio telephone network 2 is a mobile communication network, for example. The WLAN-AP 3 is a gateway for the LAN 4 in the wireless telephone network 2, and is connected to the wireless telephone network 2 on the one hand and connected to the LAN 4 on the other hand. The LAN 4 is a local area network such as Ethernet (registered trademark). The telephone main device 5 is a server connected to the LAN 4, and is a telephone exchange device that forms one VPN together with the cellular phone terminal 1 and the fixed telephone terminal 6 and mainly interconnects telephone terminals in the company. It is represented by, for example, a main device of a key telephone device or an in-house exchange that accommodates an extension telephone connected to a LAN.

  The telephone main device 5 may be connected to another telephone system via the Internet not shown as a proxy server. That is, the general Internet may be used as the IP network, and the mobile phone terminal 1, the WLAN-AP 3, and the telephone main device 5 connected via the IP network form a VPN that is one in-house switching system.

  The fixed telephone terminal 6 is a multi-function telephone, and has a multi-function button separately from the pad for dial number transmission. For example, a transfer button sends a control signal to the telephone main unit 5 via the LAN 4. be able to.

  As described above, the cellular phone terminal 1 does not have an extra key or button for light weight and miniaturization, and also transmits a control signal such as a transfer as an audio signal as a PB signal using a dial pad button. There is a standard type.

  That is, one of the features in the present invention is the mobile phone terminal 1. The cellular phone terminal 1 makes a control request to the telephone main device such as a transfer request during a call by a PB signal by dial pad operation. Therefore, the mobile phone terminal 1 generates DTMF, which is a PB signal, by a user's button pressing operation when making a control request during communication. The operation of the control request is detected by exceeding a predetermined time. As a result, when a predetermined control signal is transmitted from the dial pad, the cellular phone terminal 1 generates an RTP packet based on the in-band DTMF signal according to the detected DTMF as a voice packet, and uses a series of voice signals together with the call voice. Send to the wireless telephone network 2. Thereby, even if it is a control signal, the function which converts the in-band DTMF signal into the out-band signal for control signals is made unnecessary for the mobile phone terminal 1 during a call. That is, the present invention is characterized in that the standard mobile phone terminal 1 can be used. Incidentally, the function of converting an in-band DTMF signal into an out-band signal for a control signal is necessary, for example, when sending a call connection request or a call setup message. Therefore, it is not transmitted to the radio telephone network 2 by a series of audio signals together with the call audio, and it is not necessary to add a special conversion function.

  Here, with reference to FIG. 1, the operation from the call to the response in the present invention will be described. When a call is made, a call connection request RTP packet is sent from the cellular phone terminal 1 to the telephone main device 5 through the wireless telephone network 2, WLAN-AP 3 and LAN 4, and as a result, the telephone main device 5 transmits DT. The packet is returned and the mobile phone terminal 1 generates a dial tone. As a result, in the mobile phone terminal 1, the destination telephone number is PB dialed by the user. However, the in-band DTMF is included in a series of control signals for a call connection request, and reaches the telephone main unit 5 via the radio telephone network 2, the WLAN-AP 3 and the LAN 4 by an RTP packet of an out-band signal. The telephone main unit 5 extracts the dial number from the out-band signal, makes a call connection, and sends a call signal to the telephone terminal of the called party. On the other hand, the caller sends a ringing tone as an RTP packet. These audio signals are included in the out-band signal and are distinguished from the in-band signal.

  When the callee's telephone terminal responds, a voice signal via the LAN 4 is transmitted between the caller's mobile phone terminal 1 and the callee's, for example, the fixed telephone terminal 6 via the LAN 4. It is directly sent and received as a voice packet by a DTMF signal and does not go through the telephone main device 5.

  Next, the WLAN-AP 3 which is the main feature of the present invention will be described with reference to FIG. In the figure, the WLAN-AP 3 includes a wireless network IF (interface) 11, a packet conversion transmission unit 12, a LANIF 13, a signal transmission control unit 14, a voice packet decoding unit 15, an IB-DTMF detection unit 16, and an OB-DTMF generation unit 17. Is shown.

  The wireless network IF 11 exchanges RTP packets with the mobile phone terminal 1 via the wireless telephone network 2. That is, the radio network IF 11 sends the RTP packet received from the radio telephone network 2 to the packet conversion transmission unit 12 and the voice packet decoding unit 15, and sends the RTP packet received from the packet conversion transmission unit 12 to the radio telephone network 2. The packet conversion / transmission unit 12 is located between the wireless network IF 11 and the LAN IF 13, and performs code conversion or protocol conversion so that RTP packets to be exchanged match each network. The LANIF 13 exchanges RTP packets with the telephone main device 5 via the LAN 4. That is, the LANIF 13 sends the RTP packet received from the packet conversion transmission unit 12 and the OB-DTMF generation unit 17 to the LAN 4 and sends the RTP packet received from the LAN 4 to the packet conversion transmission unit 12. The signal transmission control unit 14 is connected to each component and controls signal transmission based on a predetermined program.

  The voice packet decoding unit 15 decodes a voice packet received by the wireless network IF 11 into a voice signal and sends the voice signal to the IB-DTMF detection unit 16. The IB-DTMF detection unit 16 detects DTMF satisfying a predetermined length from the voice signal sent from the voice packet decoding unit 15 as an in-band DTMF signal, forms a DTMF signal of a predetermined length, and sends the DTMF signal to the OB-DTMF generation unit 17. . The OB-DTMF generation unit 17 converts the received in-band DTMF signal into a predetermined out-band DTMF signal corresponding to each frequency of the DTMF when the received in-band DTMF signal matches the preset control signal data and generates the same. To the LANIF 13. In-band DTMF signals without a corresponding DTMF are discarded.

  At this time, the WLAN-AP 3 sends an in-band signal as a voice packet to the destination telephone terminal as a voice signal, and sends an out-band signal as a control signal to the telephone main unit 5. That is, as described above, when the destination of the RTP packet of the voice signal by DTMF is a telephone terminal, the DTMF is an in-band DTMF signal, and when the destination of the RTP packet is a telephone main unit, it is an out-band as a control signal. It is defined as a DTMF signal.

  In this way, the WLAN-AP 3 monitors the voice signal during a call and makes an in-band DTMF signal converted from a voice packet into a predetermined control signal so that the mobile phone terminal 1 can be used as a multi-function terminal. To detect. The detected in-band DTMF signal is converted from a telephone terminal address to a telephone main apparatus address. The form of the out-band DTMF signal is a feature of the present invention. This control signal is multiplexed and transmitted on the digital line by an RTP packet by an out-band signal destined for the address of the telephone main unit 5. Therefore, a control signal based on an in-band DTMF signal transmitted from the mobile phone terminal 1 during a call is converted into an out-band DTMF signal by the WLAN-AP 3 and taken out by the telephone main device 5 through the LAN 4. Details of main operation procedures in the WLAN-AP 3 will be described next with reference to flowcharts.

  FIG. 3 is an explanatory diagram showing a main operation procedure in a state where voice packets are directly exchanged between telephone terminals during a call centering on the WLAN-AP 3 in the present invention with reference to FIGS. 1 and 2 in a flowchart. It is.

  The WLAN-AP 3 receives a voice packet received from the wireless telephone network 2 during communication by the cellular phone terminal 1 by the wireless network IF 11 and transfers it from the packet conversion transmission unit 12 to the LAN 4 via the LAN IF 13 (step S1). The voice packet is, for example, the fixed telephone terminal 6 whose destination is the communication destination. In WLAN-AP3, since multiplexed RTP packets are transferred to a plurality of mobile phone terminals, the voice packet decoding unit 15 detects and decodes voice packets from the RTP packets received by the wireless network IF 11 (procedures). S2). The call voice is a complex combination of voice frequencies, but the control signal by the PB dial is a combination of two frequencies that are stable in a short time by the user pressing a button. Therefore, the presence of the in-band DTMF signal (YES in step S3) can be determined by detecting the DTMF exceeding the predetermined length by the IB-DTMF detector 16. The detected in-band DTMF signal is converted into an out-band DTMF signal by the OB-DTMF generation unit 17 and generated as a control signal (step S4), and then sent to the telephone 4 via the LANIF 13 to the telephone main unit 5. (Procedure S5) is performed.

  If the procedure S3 is “NO” and not an in-band DTMF signal, the detected voice packet is discarded, and the procedure returns to the procedure S1.

  Next, the telephone main device 5 which is one of the features of the present invention will be described with reference to FIG. In the telephone main device 5 shown in the figure, a LANIF 21, an RTP packet generator 22, an RTP packet detector 23, an OB-DTMF detector 24, a DTMF converter 25, a DTMF correspondence controller 26, and a call controller 27 are shown. .

  The LANIF 21 has an interface with the LAN 4 and exchanges RTP packets. Under the control of the call control unit 27, the RTP packet generation unit 22 generates an RTP packet to be sent to the LAN 4 and sends it to the LANIF 21. The RTP packet at the call connection stage includes a voice packet with an audible frequency such as voice and DTMF. For example, as a voice packet destined for the caller, a DT (dial tone) packet or an RBT (ringing tone) packet is generated as an RTP packet and sent to the LANIF 21. The RTP packet detection unit 23 detects an RTP packet received from the LAN 4 by the LANIF 21, extracts a control signal, and notifies the call control unit 27 for incoming / outgoing call connection control.

  The OB-DTMF detector 24 detects an out-band DTMF signal from the RTP packet received by the LANIF 21 from the LAN 4 and sends it to the DTMF converter 25 as a control signal. The DTMF conversion unit 25 converts the received out-band DTMF signal into a DTMF signal and sends it to the DTMF correspondence control unit 26. The out-band DTMF signal and the in-band DTMF signal include the same DTMF, and no special conversion other than the address is necessary. The DTMF correspondence control unit 26 compares the received DTMF with a predetermined DTMF, determines a control signal set other than, for example, a dial number, and executes connection control given to the control signal. The DTMF correspondence control unit 26 requests the call control unit 27 to perform control if necessary for connection control. The call control unit 27 is connected to call connection-related components in the telephone main device 5 and controls its main operation. A special number other than the dial number is appropriate for the control signal itself. Incidentally, for example, a transfer destination number associated with transfer is received as a dial number in DTMF, but it is included in the transfer request control signal and is not a single DTMF signal.

  By adopting such a configuration, when a PB signal is transmitted from the dial pad during a call, it can be converted to an out-band DTMF signal by the LAN adapter and sent to the telephone main unit. Therefore, first, since it is not necessary to convert a control signal by DTMF into an out-band signal even in a mobile phone terminal, a standard telephone having only an in-band DTMF transmission function can be adopted. Second, by changing the destination address using a known in-band DTMF signal to form an out-band DTMF signal, the control signal can be easily generated in the telephone main unit. In addition, since all PB signals sent from the dial pad during a call reach the other party's telephone terminal as an in-band DTMF signal, it is possible to receive functional services such as automatic reception by telephone.

  A second embodiment of the present invention will be described with reference to FIG.

  In the embodiment of FIG. 5, the WLAN-AP 3A is provided in the WLAN-AP 3 of FIG. The WLAN-AP 3A includes a wireless network IF 11A, a packet conversion / transmission unit 12A, a LAN IF 13A, a signal transmission control unit 14A, an RTP packet storage unit 31, a transmission packet generation unit 32, a voice packet decoding unit 33, an IB-DTMF detection unit 34, and An OB-DTMF generator 35 is shown.

  The wireless network IF 11A, the packet conversion / transmission unit 12A, the LANIF 13A, and the signal transmission control unit 14A have substantially the same functions as the components having the same names in FIG. 2, but the packet conversion / transmission unit 12A is connected from the LANIF 13A to the wireless network IF 11A. RTP packet conversion and transmission. The RTP packet conversion and transmission from the wireless network IF 11A to the LANIF 13A is executed by the RTP packet storage unit 31 and the transmission packet generation unit 32. The voice packet decoding unit 33, the IB-DTMF detection unit 34, and the OB-DTMF generation unit 35 also have substantially the same functions as the components having the same names in FIG.

  The RTP packet storage unit 31 temporarily stores RTP packets received by the wireless network IF 11A. The transmission packet generation unit 32 extracts the packet stored in the RTP packet storage unit 31, and then generates an RTP packet to be transmitted by deleting the in-band DTMF signal subjected to conversion generation by the OB-DTMF generation unit 35. The RTP packet is sent from LANIF 13A to LAN4. The voice packet decoding unit 33 extracts the voice packet from the RTP packet storage unit 31, decodes it, and sends it to the IB-DTMF detection unit 34. The IB-DTMF detector 34 detects an in-band DTMF signal from the transmitted voice packet and sends it to the OB-DTMF generator 35. When the received in-band DTMF signal matches the control signal data set in advance, the OB-DTMF generation unit 35 generates an out-band DTMF signal for the DTMF and sends it to the LAN 4 from the LANIF 13A. On the other hand, the OB-DTMF generation unit 35 notifies the transmission packet generation unit 32 of the in-band DTMF signal converted and generated into the out-band DTMF signal.

  Due to such a configuration, in this embodiment, even if the PB signal is transmitted, the DTMF converted into the control signal does not reach the other party, so that the call is not excluded by an extra audible signal. On the other hand, when the transmitted PB signal is other than a predetermined control signal, information on the PB signal can be sent to the other party via the Internet, so that, for example, functional services such as automatic application from a telephone can be received. Is possible.

  A PB signal transmitted from a telephone terminal can be easily converted from an in-band DTMF signal to an out-band DTMF signal by only an address conversion using an adapter. Therefore, the present invention provides a multi-function service without a significant expansion of conventional equipment by sending a predetermined control signal to a telephone main unit connected via a network using a standard type telephone terminal. Can be applied to necessary and indispensable uses.

It is explanatory drawing which showed the related IP telephone system by the block. It is explanatory drawing which showed the one form of WLAN-AP in FIG. 1 with the block. Example 1 It is explanatory drawing which showed the form of the main operation | movement procedure of WLAN-AP in FIG. 2 with the flowchart. Example 1 It is explanatory drawing which showed the one form of the telephone main apparatus in FIG. 1 with the block. Example 1 It is explanatory drawing which showed the form different from FIG. 2 of WLAN-AP in FIG. 1 with the block. (Example 2)

Explanation of symbols

1 Mobile phone terminal 2 Wireless telephone network 3, 3A WLAN-AP
4 LAN
5 Telephone main device 6 Fixed telephone terminal 11, 11A Wireless network IF
12, 12A Packet conversion transmission unit 13, 13A, 21 LANIF
14, 14A Signal transmission control unit 15, 33 Voice packet decoding unit 16, 34 IB-DTMF detection unit 17, 35 OB-DTMF generation unit 22 RTP packet generation unit 23 RTP packet detection unit 24 OB-DTMF detection unit 25 DTMF conversion unit 26 DTMF compatible control unit 27 Call control unit 31 RTP packet storage unit 32 Outgoing packet generation unit

Claims (6)

  When an in-band DTMF signal transmitted to the IP network is detected by a PB signal from a telephone terminal communicating in a telephone system configured with an IP network, the DTMF signal obtained from the in-band DTMF signal is left as it is. A signal control method for generating and transmitting an out-band DTMF signal by substituting a telephone main device address.   When an in-band DTMF signal transmitted as a PB signal is detected as a control signal from a telephone terminal communicating with a telephone system configured with an IP network, the signal is converted into an out-band signal, and the main telephone is transmitted via the IP network. A signal control method for transmitting to a device, wherein the DTMF signal obtained from the in-band DTMF signal is left as it is, the destination address is replaced, and the out-band signal is generated as an out-band DTMF signal.   3. The signal control method according to claim 2, wherein an adapter is provided between the telephone terminal and the IP network, and the in-band DTMF signal is transmitted from the telephone terminal to the adapter, and the out-band DTMF is transmitted by the adapter. A signal control method for generating a signal.   In a telephone system constituted by an IP network, an adapter for receiving a voice signal during communication is provided between the IP network and the telephone terminal, and an in-band DTMF signal transmitted as a PB signal from the telephone terminal during communication is used as a control signal. In the signal control method of converting the signal into an out-band signal when it is detected and sending it to the IP network, the adapter replaces the destination address with the DTMF signal obtained from the in-band DTMF signal as it is, and A signal control system comprising means for generating and transmitting a band signal to an out-band DTMF signal.   5. The signal control system according to claim 4, wherein the adapter temporarily stores a voice packet in communication received from the telephone terminal, and temporarily stores the in-band DTMF signal generated in the out-band DTMF signal. A signal control system comprising means for deleting from the voice packet and sending it to the IP network.   6. The signal control method according to claim 4, further comprising: connecting to the IP network to receive the outband DTMF signal from the telephone terminal as the outband signal, and including the received outband DTMF signal in the received outband DTMF signal. A signal control system comprising a telephone main unit that performs preset control corresponding to a DTMF signal.

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