JP4998903B2 - Facsimile relay device, relay method, and program - Google Patents

Description

  The present invention relates to a facsimile relay apparatus that relays communication between facsimile apparatuses, a relay method, and a program.

  Conventionally, ITU-T recommendation T.I. The following two methods are used as a method of performing facsimile communication via an IP (Internet Protocol) network using a facsimile apparatus having a facsimile communication function conforming to the 30 standard. One method is a method in which a facsimile signal transmitted by a facsimile apparatus is converted into a packet by a process similar to that performed by a facsimile relay apparatus for communication. In another method, the facsimile signal transmitted from the facsimile apparatus is transmitted to the ITU-T recommendation T.264. This is a method of performing communication by converting into a packet indicating a control signal conforming to No. 38. The ITU-T recommendation T.I. 30 is a recommendation that prescribes a communication method for facsimile communication via a telephone network. 38 is a recommendation that defines a communication method for real-time facsimile communication via an IP network.

  In Patent Document 1, when facsimile devices perform direct data communication via an IP network, data transmission can be reliably performed, and an appropriate retransmission method is selected according to the content of the communication error. Techniques to do this are disclosed.

JP 2006-054539 A

  Here, the ITU-T recommendation T.I. A facsimile apparatus having a facsimile communication function conforming to the 30 standard is an ITU-T recommendation T.30. The timer control and the retransmission control specified in 30 are performed. For this reason, when communication is performed via the IP network, if a jitter, packet loss, or packet delay occurs in the IP network, the facsimile apparatus executes a timeout process and interrupts the communication. Therefore, ITU-T recommendation T.30. When facsimile communication is performed via an IP network using a facsimile apparatus having a facsimile communication function conforming to the 30 standard, there is a problem that it is difficult to complete communication normally.

According to the technique described in Patent Document 1, the facsimile apparatus performs retransmission of a packet when a communication error occurs. However, if the communication quality of the IP network is poor, the facsimile apparatus repeats retransmission of the packet. As a result, there is a problem that it is difficult to complete the communication.
SUMMARY An advantage of some aspects of the invention is that it provides a facsimile relay apparatus, a relay method, and a program that prevent interruption of facsimile communication due to a communication failure.

The present invention has been made to solve the above-described problem, and is a facsimile relay apparatus that relays communication between a first facsimile apparatus and a second facsimile apparatus. A conversion unit that converts a received facsimile signal into a packet signal, a packet transmission unit that transmits the packet converted by the conversion unit to the second facsimile device, and a packet reception unit that receives a packet from the second facsimile device In a predetermined call connection procedure performed prior to the start of image communication, after the packet transmitter transmits a packet used for modem training to the second facsimile apparatus, the first facsimile apparatus transmits the modem. no response time until disconnecting the communication to end the wait for reception of a response indicating the success or failure of the training Until the lapse of a predetermined short time from the out time, transmits the response indicating success or failure of the modem training when the packet receiving unit does not receive a response indicating the failure in the modem training to the first facsimile machine And a retransmission request transmission unit.

According to another aspect of the present invention, there is provided a relay method using a facsimile relay device that relays communication between a first facsimile device and a second facsimile device, wherein the conversion unit receives the signal from the first facsimile device. The facsimile signal is converted into a packet signal, the packet transmission unit transmits the packet converted by the conversion unit to the second facsimile device, the packet reception unit receives the packet from the second facsimile device, and the image In a predetermined call connection procedure performed prior to the start of communication, after the packet transmission unit transmits a packet used for modem training to the second facsimile apparatus, the first facsimile apparatus determines whether or not the modem training is successful. predetermined shorter than the no-response time-out time to disconnect the communication to end the wait for reception of a response indicating the By the time elapses, it transmits the response indicating success or failure of the modem training when the packet receiving unit does not receive the retransmission request transmitting unit, a response indicating the failure in the modem training to the first facsimile machine It is characterized by.

According to another aspect of the present invention, there is provided a facsimile relay apparatus that relays communication between a first facsimile apparatus and a second facsimile apparatus, a conversion unit that converts a facsimile signal received from the first facsimile apparatus into a packet signal, A packet transmitting unit for transmitting the packet converted by the converting unit to the second facsimile device, a packet receiving unit for receiving a packet from the second facsimile device, and a predetermined call connection procedure performed prior to the start of image communication The packet transmission unit transmits a packet used for modem training to the second facsimile apparatus, and then the first facsimile apparatus ends waiting for reception of a response indicating success or failure of the modem training and performs communication. by no response timeout shorter predetermined time than the time until the cutting has passed, the If a response indicating success or failure of modem training is not received by the packet receiving section is the program for functioning as a retransmission request transmitting unit, which transmits a response indicating the failure in the modem training to the first facsimile machine .

  According to the present invention, when the facsimile relay apparatus fails to receive a response until a predetermined time, which is shorter than the no-response timeout time, has elapsed since the time when the first facsimile apparatus transmitted the facsimile signal, A retransmission request signal is output to one facsimile machine. As a result, the first facsimile apparatus receives the response signal or the retransmission request signal before the no-response timeout period elapses, so that the facsimile communication can be continued without interrupting the communication.

1 is a schematic block diagram illustrating a configuration of a facsimile system according to an embodiment of the present invention. It is a flowchart which shows operation | movement of a facsimile relay apparatus. FIG. 10 is a sequence diagram illustrating an operation of facsimile communication when there is no communication deterioration. It is a sequence diagram which shows the operation | movement of facsimile communication when transmission of a DIS signal fails. It is a sequence diagram which shows the operation | movement of facsimile communication when transmission of a DCS signal fails. It is a sequence diagram which shows the operation | movement of facsimile communication when transmission of a CFR signal fails. It is a schematic block diagram which shows the structure of other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic block diagram showing the configuration of a facsimile system according to an embodiment of the present invention.
The facsimile system according to the present embodiment includes facsimile apparatuses 10-1 and 10-2 (hereinafter, the facsimile apparatuses 10-1 and 10-2 are collectively referred to as a facsimile apparatus 10) and facsimile relay apparatuses 100-1 and 100. -2 (hereinafter, the facsimile relay apparatuses 100-1 and 100-2 are collectively referred to as the facsimile relay apparatus 100).
The facsimile apparatus 10-1 is connected to the facsimile relay apparatus 100-1 by a wire. Communication conforming to 30 is performed.
The facsimile apparatus 10-2 is connected to the facsimile relay apparatus 100-2 by a wire. Communication conforming to 30 is performed.
Facsimile relay apparatuses 100-1 and 100-2 are connected to each other via an IP network. The facsimile relay apparatuses 100-1 and 100-2 convert the facsimile signals received from the facsimile apparatus 10 connected by wire into packets. -2 is transferred.

The facsimile relay apparatus 100 includes a facsimile communication unit 101, a communication control unit 102 (retransmission request unit), a conversion unit 103, a packet communication unit 104, and a time measuring unit 105.
The facsimile communication unit 101 performs transmission / reception processing of a facsimile signal with the facsimile apparatus 10 connected by wire.
The communication control unit 102 communicates with the facsimile apparatus 10 connected by wire via the facsimile communication unit 101 and the ITU-T recommendation T.264. Communication conforming to 30 is performed.
The conversion unit 103 converts the facsimile signal received by the facsimile communication unit 101 into a packet, and converts the packet received by the packet communication unit 104 into a facsimile signal.
The packet communication unit 104 performs packet transmission / reception processing with the facsimile relay apparatus 100 connected via the IP network.
The time measuring unit 105 measures the elapsed time from the time when the packet communication unit 104 transmits the packet. In addition, the time measuring unit 105 stores a retransmission request time (predetermined time) which is a time (for example, 3 seconds) shorter than a no-response timeout time (for example, 5 seconds) preset in the facsimile apparatus 10 connected by wire. To remember. The no-response time-out time is a time from the time when the facsimile apparatus 10 transmits a facsimile signal to the time when the reception of the response is terminated and the communication is disconnected. The retransmission request time may be registered by the administrator of the facsimile relay apparatus 100, or automatically based on the no-response timeout time read from the facsimile apparatus 10 to which the facsimile relay apparatus 100 is connected by wire. It may be registered in.

Then, the conversion unit 103 of the facsimile relay apparatus 100-1 according to the present embodiment converts the facsimile signal received from the facsimile apparatus 10-1 into a packet signal, and the packet communication unit 104 transmits the packet converted by the conversion unit 103 to the facsimile. Transmit to device 10-2. The packet communication unit 104 receives a packet from the facsimile machine 10-2.
Then, in a predetermined call connection procedure performed prior to the start of image communication, after the packet communication unit 104 transmits a packet to the facsimile machine 10-2, a retransmission request shorter than the no-response timeout time by the facsimile machine 10-1. If the packet communication unit 104 does not receive a response to the transmitted packet before the time elapses, the communication control unit 102 transmits a retransmission request signal requesting retransmission of the facsimile signal to the facsimile apparatus 10-1.
Thereby, the facsimile relay apparatus 100-1 can prevent interruption of facsimile communication due to communication failure.

Next, the operation of the facsimile relay apparatus 100-1 according to the present embodiment will be described. Although the operation of the facsimile relay apparatus 100-1 will be described here, the operation of the facsimile relay apparatus 100-2 is the same as that of the facsimile relay apparatus 100-1.
First, an operation when the facsimile relay apparatus 100-1 receives a packet indicating a facsimile signal from the facsimile relay apparatus 100-2 will be described.
When the facsimile relay apparatus 100-2 transmits a packet indicating a facsimile signal to the facsimile relay apparatus 100-1, the packet communication unit 104 of the facsimile relay apparatus 100-1 receives the packet. Next, the conversion unit 103 converts the received packet into an ITU-T recommendation T.264. 30 is converted into a facsimile signal conforming to the standard No. 30. Then, the communication control unit 102 transmits the converted facsimile signal to the facsimile machine 10-1 via the facsimile communication unit 101.
As a result, the facsimile relay apparatus 100-1 can transfer the packet received from the facsimile relay apparatus 100-2 to the facsimile apparatus 10-1 as a facsimile signal.

Next, the operation when the facsimile relay apparatus 100-1 receives a facsimile signal from the facsimile apparatus 10-1 in phase B (data link establishment phase) will be described. Note that Phase B is ITU-T recommendation T.30. 30 is a call connection procedure defined prior to the start of image communication.
FIG. 2 is a flowchart showing the operation of the facsimile relay apparatus.
When the facsimile apparatus 10-1 outputs a facsimile signal, the facsimile communication unit 101 of the facsimile relay apparatus 100-1 receives the facsimile signal (step S1). Next, the communication control unit 102 determines the type of the facsimile signal received by the facsimile communication unit 101 (step S2).

  Specifically, the type of facsimile signal in Phase B includes a DIS signal (Digital Identification Signal) indicating information (for example, telephone number, paper width, resolution, etc.) of the facsimile apparatus 10-1, and a DIS signal. DCS signal (Digital Command Signal: digital command signal) indicating communication conditions (for example, modem speed, paper width, resolution, etc.), and TCF signal (Training Check Field: training check signal) used for modem training ), A CFR signal (Confirmation to Receive: reception preparation confirmation signal) indicating a response to the TCF signal and indicating that the modem training has been successful, and a TCF signal FTT signal (Failure To Train) indicating that the modem training has failed, and a CRP signal (Command) indicating that the previous command has been received in error and needs to be retransmitted. (Repeat: command retransmission signal).

  When determining that the received facsimile signal is a DIS signal (step S2: DIS), the communication control unit 102 uses an ECM (Error Correction Mode: automatic error correction mode) among the transmission parameters included in the received DIS signal. The parameter indicating whether or not to perform communication is rewritten to logic off (step S3). That is, the communication control unit 102 is set not to retransmit the image signal in phase C (information transmission phase) regardless of whether there is an error in the image signal.

Here, the reason why the communication control unit 102 is set not to retransmit the image signal regardless of whether there is an error in the image signal in the phase C will be described.
When communication is performed between the facsimile apparatuses 10-1 and 10-2 with ECM enabled, if the receiving facsimile apparatus 10 detects a data error in phase C, only the image signal in which the error is detected is transmitted to the transmitting facsimile apparatus. 10 can be retransmitted. However, if the quality of the IP network is poor, when communication is performed with ECM enabled, it is not possible to proceed to phase D (message transmission completion confirmation phase) to repeat transmission until there is no data error, and communication is performed due to timeout. There is a risk of interruption. Therefore, the communication can be normally terminated by invalidating the ECM and performing communication in which data error is allowed in phase C.
For this reason, the communication control unit 102 turns off the ECM of the DIS signal in step S3.

  When the communication control unit 102 logically turns off the ECM of the DIS signal in step S3, the conversion unit 103 converts the DIS signal in which the ECM is logically turned off into a packet (step S4). Note that the conversion unit 103 may convert a facsimile signal into a packet by a process similar to that for voice, or may include an ITU-T recommendation T.264. Alternatively, the packet may be converted into a packet indicating a control signal conforming to H.38. Then, the packet communication unit 104 transmits the converted packet to the facsimile relay apparatus 100-2 via the IP network (step S5). In addition, the time measuring unit 105 starts measuring the elapsed time from the packet transmission time (step S6).

  When the time measuring unit 105 starts measuring the elapsed time from the packet transmission time, the packet communication unit 104 receives a DCS signal indicating a condition for performing communication from the facsimile relay apparatus 100-2 as a response to the packet indicating the transmitted DIS signal. It is determined whether or not a packet indicating is received (step S7). Specifically, it is determined whether or not the packet communication unit 104 has received a packet from the facsimile relay apparatus 100-2. If the packet communication unit 104 has received a packet, the conversion unit 103 further converts the packet into a facsimile signal. Is a DCS signal.

When the packet communication unit 104 determines that a packet indicating a DCS signal has been received from the facsimile relay apparatus 100-2 (step S7: YES), the packet received from the facsimile relay apparatus 100-2 is transmitted to the facsimile signal by the above-described processing. And transmitted to the facsimile machine 10-1. Then, the facsimile relay apparatus 100-1 ends the process.
On the other hand, when it is determined that the packet communication unit 104 has not received a packet indicating a DCS signal from the facsimile relay apparatus 100-2 (step S7: YES), the time measuring unit 105 determines that the elapsed time from the packet transmission time is It is determined whether or not the retransmission request time stored in the internal memory has elapsed (step S8).

When the time measuring unit 105 determines that the elapsed time from the packet transmission time has not passed the retransmission request time (step S8: NO), the process returns to step S7 to determine again whether or not a packet indicating a DCS signal has been received. .
On the other hand, when the time measuring unit 105 determines that the elapsed time from the packet transmission time has passed the retransmission request time (step S8: YES), the communication control unit 102 transmits the facsimile apparatus 10 via the facsimile communication unit 101. −1, a CRP signal (retransmission request signal) indicating that the DIS signal needs to be retransmitted is transmitted (step S9), and the process ends.

  At this time, the retransmission request time from the end of the reception of the response to the packet transmitted by the facsimile relay apparatus 100-1 to the output of the DCS signal to the facsimile apparatus 10-1 is the waiting time for the facsimile apparatus 10 to receive the response. Is shorter than the no-response timeout period until the communication is terminated after quitting. Accordingly, the facsimile relay apparatus 100-1 transmits a response signal (DCS signal or CRP signal) to the facsimile apparatus 10-1 before the no-response timeout period elapses from the time when the facsimile apparatus 10-1 transmits the DIS signal. be able to. Therefore, the facsimile apparatus 10-1 receives the response signal before the no-response timeout time elapses, and can continue the facsimile communication without interrupting the communication.

  If the communication control unit 102 determines in step S2 that the received facsimile signal is a TCF signal used for modem training (step S2: TCF), the communication control unit 102 converts the received TCF signal into a packet (step S10). The packet communication unit 104 transmits the converted packet to the facsimile relay apparatus 100-2 via the IP network (step S11). In addition, the time measuring unit 105 starts measuring the elapsed time from the packet transmission time (step S12).

  When the time counting unit 105 starts measuring the elapsed time from the packet transmission time, the packet communication unit 104 indicates that the modem training is successful from the facsimile relay apparatus 100-2 as a response to the packet indicating the transmitted TCF signal. It is determined whether a packet indicating a CFR signal or a packet indicating an FTT signal indicating that modem training has failed has been received (step S13).

If it is determined that the packet communication unit 104 has received either a CFR signal or a packet indicating an FTT signal from the facsimile relay apparatus 100-2 (step S13: YES), the packet communication unit 104 converts the packet into a facsimile signal by the above-described processing. And transmitted to the facsimile machine 10-1. Then, the facsimile relay apparatus 100-1 ends the process.
On the other hand, when the packet communication unit 104 determines that neither the packet indicating the CFR signal nor the packet indicating the FTT signal has been received from the facsimile relay apparatus 100-2 (step S13: NO), the time counting unit 105 It is determined whether or not the elapsed time from the packet transmission time has passed the retransmission request time stored in the internal memory (step S14).

When the time measuring unit 105 determines that the elapsed time from the packet transmission time has not passed the retransmission request time (step S14: NO), the process returns to step S13, and whether or not a packet indicating the CFR signal or the FTT signal is received again Determine.
On the other hand, when the time counting unit 105 determines that the elapsed time from the packet transmission time has passed the retransmission request time (step S14: YES), the communication control unit 102 passes the facsimile apparatus 10 via the facsimile communication unit 101. -1 is transmitted with an FTT signal (transmission request signal) indicating that the modem training has failed (step S15), and the process is terminated.

  As described above, the retransmission request time from when the facsimile relay apparatus 100-1 waits for reception of a response to the packet transmitted to when the DCS signal is output to the facsimile apparatus 10-1 is determined when the facsimile apparatus 10 receives the response. It is shorter than the no-response timeout period until the communication is disconnected after waiting for Accordingly, the facsimile relay apparatus 100-1 transmits a response signal (CFR signal or FTT signal) to the facsimile apparatus 10-1 before the no-response timeout period elapses from the time when the facsimile apparatus 10-1 transmits the TCF signal. can do. Therefore, the facsimile apparatus 10-1 receives the response signal before the no-response timeout time elapses, and can continue the facsimile communication without interrupting the communication.

  If the communication control unit 102 determines in step S2 that the received facsimile signal is neither a DIS signal nor a TCF signal (step S2: other), the communication control unit 102 converts the received facsimile signal into a packet (step S16). . Then, the packet communication unit 104 transmits the converted packet to the facsimile relay apparatus 100-2 via the IP network (step S17), and ends the process.

  In the phase B processing, among the facsimile signals received by the facsimile relay apparatus 100-1 from the facsimile apparatus 10-1, a facsimile signal that is neither a DIS signal nor a TCF signal is received from the facsimile apparatus 10-2. This is a response (DCS signal, CRP signal, CFR signal, FTT signal) to a signal or TCF signal. And ITU-T recommendation T.I. At 30, it is not stipulated to send a response to these signals.

  In the phases other than Phase B, the facsimile relay apparatuses 100-1 and 100-2 convert the facsimile signal into a packet by the same operation as the operation when the signal type is “Other” in the processing of Phase B. , To the opposite facsimile relay apparatus 100.

Hereinafter, the operation of facsimile communication in the facsimile system according to the present embodiment will be described using a specific example.
FIG. 3 is a sequence diagram showing an operation of facsimile communication when there is no communication deterioration.
First, when the facsimile apparatus 10-2 receives an incoming call from the facsimile apparatus 10-1 and establishes a call in phase A, the facsimile apparatus 10-2 transmits a DIS signal indicating information of the facsimile apparatus 10-2 to the facsimile relay apparatus 100-2 (Step S1). S101). Next, the facsimile relay apparatus 100-2 sets the ECM parameter included in the DIS signal to OFF in step S3 described above, and transmits a packet indicating the DIS signal to the facsimile relay apparatus 100-1 (step S102). . At this time, the facsimile relay apparatus 100-2 starts measuring the elapsed time from the time when the DIS signal is transmitted in step S6 described above. Next, the facsimile relay apparatus 100-1 converts the received packet into a DIS signal and transmits it to the facsimile apparatus 10-1 (step S103).

When the facsimile apparatus 10-1 receives the DIS signal, the facsimile apparatus 10-1 transmits a DCS signal indicating a condition for performing communication as a response to the DIS signal to the facsimile relay apparatus 100-1 (step S104). The facsimile relay apparatus 100-1 converts the received DCS signal into a packet, and transmits the packet to the facsimile relay apparatus 100-2 (step S105). Since the facsimile relay apparatus 100-2 receives the packet within the retransmission request time from the time when the DIS signal is transmitted, the facsimile relay apparatus 100-2 converts the received packet into a DCS signal and transmits it to the facsimile apparatus 10-2 (step S106).
The facsimile machine 10-2 determines parameters for facsimile communication based on the received DCS signal.

  Further, when the facsimile apparatus 10-1 transmits the DCS signal in step S104, the facsimile apparatus 10-1 transmits a TCF signal used for modem training to the facsimile relay apparatus 100-1 (step S107). Next, the facsimile relay apparatus 100-1 converts the received TCF signal into a packet and transmits the packet to the facsimile relay apparatus 100-2 (step S108). At this time, the facsimile relay apparatus 100-2 starts measuring the elapsed time from the time when the TCF signal is transmitted in step S12 described above. Next, the facsimile relay apparatus 100-2 converts the received packet into a TCF signal and transmits it to the facsimile apparatus 10-2 (step S109).

When the facsimile apparatus 10-2 receives the TCF signal, the facsimile apparatus 10-2 performs modem training based on the TCF signal and checks whether communication with the facsimile apparatus 10-1 is possible. When it is determined that communication is possible, a CFR signal, which is a response indicating that modem training is successful, is transmitted to the facsimile relay apparatus 100-2 as a response to the TCF signal (step S110). The facsimile relay apparatus 100-2 converts the received CFR signal into a packet, and transmits the packet to the facsimile relay apparatus 100-1 (step S111). Since the facsimile relay apparatus 100-1 receives the packet within the retransmission request time from the time when the TCF signal is transmitted, the facsimile relay apparatus 100-1 converts the received packet into a CFR signal and transmits it to the facsimile apparatus 10-1 (step S112).
Then, the facsimile apparatuses 10-1 and 10-2 make a transition to phase C and start communication of image signals (step S113). At this time, since the ECM parameter of the DIS signal is turned off in step S102 described above, the facsimile apparatuses 10-1 and 10-2 perform communication of the image signal without detecting data errors in the phase C. Do.

Next, an operation when the transmission of the DIS signal fails in the facsimile system according to the present embodiment will be described.
FIG. 4 is a sequence diagram showing an operation of facsimile communication when transmission of a DIS signal fails.
First, when the facsimile apparatus 10-2 receives a call from the facsimile apparatus 10-1 and establishes the call in phase A, the facsimile apparatus 10-2 transmits a DIS signal indicating information of the facsimile apparatus 10-1 to the facsimile relay apparatus 100-2. (Step S101). Next, the facsimile relay apparatus 100-2 transmits a packet indicating the received DIS signal to the facsimile relay apparatus 100-1 (step S102). At this time, the facsimile relay apparatus 100-2 starts measuring the elapsed time from the time when the DIS signal is transmitted in step S6 described above.

  Here, when the facsimile relay apparatus 100-1 cannot receive a packet due to a packet loss or the like, the facsimile apparatus 10-1 cannot receive a DIS signal, and therefore a DCS signal as a response signal is not transmitted. As a result, the facsimile relay apparatus 100-2 determines that the packet has not been received within the retransmission request time from the time when the DIS signal is transmitted, and a CRP signal indicating that the signal needs to be retransmitted as a response to the DIS signal. Is transmitted to the facsimile machine 10-2 (step S201).

When the facsimile apparatus 10-2 receives the CRP signal, it again transmits a DIS signal to the facsimile relay apparatus 100-2 (step S202). Next, the facsimile relay apparatus 100-2 transmits a packet indicating the received DIS signal to the facsimile relay apparatus 100-1 (step S203). Next, the facsimile relay apparatus 100-1 converts the received packet into a DIS signal and transmits it to the facsimile apparatus 10-1 (step S204).
When the facsimile apparatus 10-1 receives the DIS signal, the facsimile apparatus 10-1 transmits a DCS signal indicating a communication condition to the facsimile relay apparatus 100-1 as a response to the DIS signal (step S104).
Thereafter, the facsimile communication is executed by the same operation as the operation of the facsimile communication when there is no communication deterioration. As a result, the facsimile machine 10-1 can continue facsimile communication without interrupting communication.

Next, the operation when the transmission of the DCS signal fails in the facsimile system according to the present embodiment will be described.
FIG. 5 is a sequence diagram showing an operation of facsimile communication when transmission of a DCS signal fails.
Note that, in the processes in steps S101 to S103, the facsimile communication is executed by the same operation as the operation of the facsimile communication in the case where there is no deterioration of the communication described above.
When the processing of steps S101 to S103 is executed, when the facsimile apparatus 10-1 receives a DIS signal from the facsimile apparatus 10-2 via the facsimile relay apparatuses 100-1 and 100-2, a response to the DIS signal is received. Then, a DCS signal indicating a condition for performing communication is transmitted to the facsimile relay apparatus 100-1 (step S104).
Next, the facsimile relay apparatus 100-1 transmits a packet indicating the received DCS signal to the facsimile relay apparatus 100-2 (step S105).

  Here, when the facsimile relay apparatus 100-2 cannot receive the packet due to a packet loss or the like, the facsimile relay apparatus 100-2 determines that the packet has not been received within the retransmission request time from the time when the DIS signal is transmitted. Then, as a response to the DIS signal, a CRP signal indicating that the signal needs to be retransmitted is transmitted to the facsimile machine 10-2 (step S301).

  When the facsimile apparatus 10-2 receives the CRP signal, it again transmits a DIS signal to the facsimile relay apparatus 100-2 (step S302). Next, the facsimile relay apparatus 100-2 transmits a packet indicating the received DIS signal to the facsimile relay apparatus 100-1 (step S303). Next, the facsimile relay apparatus 100-1 converts the received packet into a DIS signal and transmits it to the facsimile apparatus 10-1 (step S304).

When the facsimile apparatus 10-1 receives the DIS signal, the facsimile apparatus 10-1 transmits a DCS signal indicating a communication condition to the facsimile relay apparatus 100-1 as a response to the DIS signal (step S305). Next, the facsimile relay apparatus 100-1 converts the received DCS signal into a packet, and transmits the packet to the facsimile relay apparatus 100-2 (step S306). Next, the facsimile relay apparatus 100-2 converts the received packet into a DCS signal and transmits it to the facsimile apparatus 10-2 (step S307).
Thereafter, the facsimile communication is executed by the same operation as the operation of the facsimile communication when there is no communication deterioration. As a result, the facsimile machine 10-1 can continue facsimile communication without interrupting communication.

Next, the operation when the transmission of the DCS signal fails in the facsimile system according to the present embodiment will be described.
FIG. 6 is a sequence diagram showing an operation of facsimile communication when transmission of the CFR signal fails.
Note that, in the processes in steps S101 to S109, the facsimile communication is executed by the same operation as the operation of the facsimile communication in the case where there is no deterioration of the communication described above.
When the processing of step S101 to step S109 is executed, the facsimile apparatus 10-2 receives the TCF signal used for modem training from the facsimile apparatus 10-1 via the facsimile relay apparatuses 100-1 and 100-2. As a response to the TCF signal, a CFR signal indicating that the modem training is successful is transmitted to the facsimile relay apparatus 100-2 (step S110).
Next, the facsimile relay apparatus 100-2 transmits a packet indicating the received CFR signal to the facsimile relay apparatus 100-1 (step S111).

  Here, when the facsimile relay apparatus 100-1 cannot receive the packet due to a packet loss or the like, the facsimile relay apparatus 100-1 determines that the packet has not been received within the retransmission request time from the time when the TCF signal is transmitted. Then, as a response to the TCF signal, an FTT signal indicating that the modem training is successful is transmitted to the facsimile machine 10-1 (step S401).

  When the facsimile apparatus 10-1 receives the FTT signal, the facsimile apparatus 10-1 transmits the TCF signal to the facsimile relay apparatus 100-1 again (step S402). Next, the facsimile relay apparatus 100-1 transmits a packet indicating the received TCF signal to the facsimile relay apparatus 100-2 (step S403). Next, the facsimile relay apparatus 100-2 converts the received packet into a TCF signal and transmits it to the facsimile apparatus 10-2 (step S404).

When the facsimile apparatus 10-2 receives the TCF signal, the facsimile apparatus 10-2 transmits the CFR signal to the facsimile relay apparatus 100-2 as a response to the TCF signal (step S305). Next, the facsimile relay apparatus 100-2 converts the received CFR signal into a packet and transmits the packet to the facsimile relay apparatus 100-1 (step S406). Next, the facsimile relay apparatus 100-1 converts the received packet into a CFR signal and transmits it to the facsimile apparatus 10-1 (step S407).
Then, the facsimile apparatuses 10-1 and 10-2 make a transition to phase C and start communication of image signals (step S113). As a result, the facsimile machine 10-1 can continue facsimile communication without interrupting communication.

  As described above, according to the present embodiment, the facsimile relay apparatus 100 has received a retransmission request time that is shorter than the no-response timeout time from the time when the facsimile apparatus 10 connected by wire transmits a facsimile signal. When a response signal cannot be received from the opposing facsimile relay apparatus 100, a negative response signal is output to the facsimile apparatus 10. That is, the facsimile relay apparatus 100 transmits a response signal to the facsimile apparatus 10 before the no-response timeout time elapses. Therefore, the facsimile apparatus 10 receives the response signal before the no-response timeout time elapses, and can continue facsimile communication without interrupting communication.

As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to
For example, in the facsimile system according to the first embodiment, the case where the facsimile relay apparatus 100-1 performs communication while facing the facsimile relay apparatus 100-2 has been described, but the present invention is not limited to this.

FIG. 7 is a schematic block diagram showing the configuration of another embodiment of the present invention.
The facsimile system shown in FIG. 7 includes facsimile apparatuses 10-1 and 10-2, a facsimile relay apparatus 100, and a key telephone apparatus 200.
The facsimile apparatus 10-1 is connected to the facsimile relay apparatus 100.
The facsimile relay apparatus 100 is connected to a regional IP network via an IP line.
The facsimile apparatus 10-2 is connected to the key telephone apparatus 200.
The key telephone device 200 is connected to a public network via a telephone line.
The regional IP network and the public network are connected to each other by a service provider network.
As described above, even when one of the facsimile apparatuses 10 is connected to the public network, the facsimile relay apparatus 100 performs the same processing as in the first embodiment, thereby suppressing the influence of the communication quality of the IP network. Communication can be performed.

  The facsimile relay apparatus 100 described above has a computer system inside. The operation of each processing unit described above is stored in a computer-readable recording medium in the form of a program, and the above processing is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  DESCRIPTION OF SYMBOLS 10, 10-1, 10-2 ... Facsimile apparatus 100, 100-1, 100-2 ... Facsimile relay apparatus 101 ... Facsimile communication part 102 ... Communication control part 103 ... Conversion part 104 ... Packet communication part 105 ... Time measuring part

Claims (4)

A facsimile relay device that relays communication between a first facsimile device and a second facsimile device,
A conversion unit that converts a facsimile signal received from the first facsimile device into a packet signal;
A packet transmission unit that transmits the packet converted by the conversion unit to the second facsimile apparatus;
A packet receiver for receiving a packet from the second facsimile machine;
In a predetermined call connection procedure performed before the start of image communication, after the packet transmission unit transmits a packet used for modem training to the second facsimile apparatus, the first facsimile apparatus performs the modem training. When the packet reception unit does not receive a response indicating success or failure of the modem training until a predetermined time shorter than the no-response timeout time until the communication is disconnected after finishing waiting for reception of the response indicating success or failure A retransmission request transmission unit that transmits a response indicating that the modem training has failed to the first facsimile apparatus;
A facsimile relay apparatus comprising: The information included in the facsimile signal received from the first facsimile apparatus, indicating whether or not to retransmit the image signal when there is an error in the image signal during image communication, retransmits the image signal. A re-transmission refusal setting section that rewrites information indicating that
The facsimile relay apparatus according to claim 1, wherein the conversion unit converts the facsimile signal whose information has been rewritten by the retransmission rejection setting unit into a packet signal. A relay method using a facsimile relay device that relays communication between a first facsimile device and a second facsimile device,
The conversion unit converts the facsimile signal received from the first facsimile apparatus into a packet signal,
The packet transmission unit transmits the packet converted by the conversion unit to the second facsimile device,
The packet receiving unit receives a packet from the second facsimile apparatus,
In a predetermined call connection procedure performed before the start of image communication, after the packet transmission unit transmits a packet used for modem training to the second facsimile apparatus, the first facsimile apparatus performs the modem training. When the packet reception unit does not receive a response indicating success or failure of the modem training until a predetermined time shorter than the no-response timeout time until the communication is disconnected after finishing waiting for reception of the response indicating success or failure The retransmission request transmission unit transmits a response indicating that the modem training has failed to the first facsimile apparatus.
Facsimile relay method characterized by the above. A facsimile relay device that relays communication between the first facsimile device and the second facsimile device;
A conversion unit that converts a facsimile signal received from the first facsimile device into a packet signal;
A packet transmission unit for transmitting the packet converted by the conversion unit to the second facsimile machine;
A packet receiver for receiving a packet from the second facsimile machine;
In a predetermined call connection procedure performed before the start of image communication, after the packet transmission unit transmits a packet used for modem training to the second facsimile apparatus, the first facsimile apparatus performs the modem training. When the packet reception unit does not receive a response indicating success or failure of the modem training until a predetermined time shorter than the no-response timeout time until the communication is disconnected after finishing waiting for reception of the response indicating success or failure A retransmission request transmission unit that transmits a response indicating that the modem training has failed to the first facsimile apparatus;
Program to function as.

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