JP5772352B2 - Communication apparatus and computer program - Google Patents

Description

  The technology disclosed in this specification relates to a communication apparatus that performs data communication according to any of a plurality of bands.

  The bandwidth-reserved data communication service is a service that uses a SIP (Session Initiation Protocol) server or a SIP adapter to perform various communications such as FAX transmission / reception via a network line. In a bandwidth-reserved network, it is possible to select and use a bandwidth (for example, 1 Mbps (megabit per second), 64 kbps (kilobit per second), etc.) in line connection units. In addition, the use band can be changed during communication.

  There is a standard called ECM (Error Correction Mode) as a communication standard used in the bandwidth reservation type data communication service. The ECM standard is a mechanism that, when an error occurs on a communication line, requests an error frame from the reception side, and the transmission side resends a normal frame corresponding to the error frame, whereby correction data can be automatically transmitted. . The ECM standard includes an RNR (Receive Not Ready) signal and an RR (receive ready request) signal. The RNR signal is a signal transmitted from the data receiving side to the data transmitting side. The RNR signal is a signal for causing the data transmission side to temporarily stop data transmission due to a decrease in processing capability on the data reception side (for example, a decrease in memory area). The RR signal is a signal transmitted from the data transmission side to the data reception side. The RR signal is a signal for inquiring the data receiving side whether or not the data transmission can be resumed. As a related technique, Patent Document 1 is disclosed.

JP 2000-349857 A

  In the bandwidth reservation type data communication service, there is a case where a charging method (time charging method) in which a communication fee according to the time required for data communication is imposed on the terminal device may be employed. In this case, every time a certain time (for example, 3 minutes) elapses, a charge for the next certain time is added. In addition, the billing amount for a certain period of time increases as the bandwidth used increases (the communication speed increases).

  In the time charging method, if the processing capability on the data receiving side is reduced and data transmission is temporarily stopped by the RNR signal, useless charging occurs during the stop period. Then, as the usage bandwidth increases, the billing amount for a certain period of time increases, and the useless billing amount during the suspension period becomes higher than necessary. In this specification, the technique which can eliminate such inconvenience is provided.

The communication device described in the present application is connected to a bandwidth reservation type network, and performs data communication with a communication destination device according to any of a plurality of bands having different communication speeds and different communication charges per charging unit time. A communication device that executes, a first transmission unit that transmits data according to a predetermined first band, a second transmission unit that transmits a first signal indicating that data has been transmitted according to the first band, and a communication destination device Is receiving a second signal indicating that the communication destination device is busy as a response to the first signal when receiving a specific signal indicating that the device is not compatible with the bandwidth reservation type network. , Stop the transmission of data by the first transmission means, and ask whether or not the band changing means for changing the band to be used to the second band slower than the first band and whether the communication destination device is busy. Characterized in that it comprises a third transmitting means for transmitting a third signal in accordance with the second band for causing I.

  In a bandwidth reservation type network that uses a communication fee per charging unit time, charging is performed even during a data transmission stop period, and therefore unnecessary charging occurs during the stop period. In the communication device described in the present application, when it is determined that the communication destination device is busy, the transmission of data is stopped and the bandwidth is changed to a second bandwidth slower than the first bandwidth. As a result, it is common for the communication fee per charging unit time to be reduced in accordance with the slowed bandwidth usage, so it is possible to prevent a situation where the unnecessary charging amount during the suspension period becomes higher than necessary. .

Further, in the communication device described in the present application , the band can be set to the second band only during a period when the communication destination device is actually busy. As a result, it is possible to prevent both a situation in which the billing amount is unnecessarily high and a reduction in time required for data communication.

When the communication destination device is not compatible with the bandwidth reservation type network, the data processing time is longer than that of the corresponding device, and it tends to be busy. In the communication device described in the present application , the band is changed from the first band to the second band only when it is detected that the communication destination device is not compatible with the band securing network. As a result, it is possible to more effectively prevent a situation where the billing amount becomes higher than necessary.

The first period from the reception of the second signal to the reception of the fourth signal is a period in which the communication destination device is busy. And, when the first period exceeds the charging unit time of the first band, by changing the band from the first band to the second band, it is possible to reliably prevent a situation in which the charging amount becomes higher than necessary It is. In the communication device described in the present application , since the bandwidth is changed only when the first period exceeds the charging unit time of the first bandwidth, it is possible to prevent a situation where a wasteful bandwidth changing process is executed.

Further, in the communication device described in the present application , it is possible to use a band with a minimum communication speed during a data transmission stop period. As a result, it is possible to more effectively prevent a situation where the billing amount becomes higher than necessary.

An example of a structure of a communication system is shown. The flowchart of an IPFAX transmission process is shown. 6 shows a flowchart of document reading processing. The flowchart of a line connection process is shown. The flowchart of a FAX transmission process is shown. The flowchart of a MCF / RNR reception process is shown. The flowchart of an UPDATE process is shown. The flowchart of a line disconnection process is shown. An example of a bandwidth accounting information table is shown. An example of SDP of an INVITE message is shown. The sequence diagram which shows operation | movement of a communication system is shown. The sequence diagram which shows operation | movement of a communication system is shown. The flowchart of a MCF / RNR reception process is shown. The flowchart of a MCF / RNR reception process is shown.

(First embodiment)
(System configuration)
A first embodiment will be described with reference to the drawings. As shown in FIG. 1, the communication system 2 includes an IP network 4, LANs 6 and 8, multi-function devices 10 and 110, a SIP server 120, and a home gateway 130. The multi-function device 10 is connected to the LAN 6. The multi-function device 110 is connected to the LAN 8 via the home gateway 130. The LANs 6 and 8 and the SIP server 120 are connected to the IP network 4. The multi-function device 10, the SIP server 120, and the multi-function device 110 can communicate with each other via the LANs 6 and 8 and the IP network 4.

  The IP network 4 is an IP network provided by a provider (Internet connection provider). The IP network 4 is controlled by the SIP server 120. An example of the IP network 4 is NGN (Next Generation Network). NGN is a next-generation IP network that replaces the current public network. In other words, the NGN is a network in which an Internet service IP network and a telephone service telephone network, which are currently constructed separately, are integrated as an IP communication network using IP technology.

  NGN has a bandwidth guarantee function. The bandwidth guarantee function is a function that can guarantee the contracted bandwidth (communication speed). In NGN, a band can be selected and connected in line connection units, and the band to be used can be changed during connection. In addition, NGN may employ a charging method (time charging method) in which a communication fee according to the time required for data communication is imposed on a terminal device in a bandwidth reservation type data communication service. The term of bandwidth guarantee may be paraphrased as “QoS (Quality of Service)”.

  The home gateway 130 is a device that exchanges data between the IP network 4 and the multi-function device 110. The home gateway 130 includes a TEL_I / F and a LAN_I / F (not shown). The multi-function device 110 is T.D. In the case of supporting 38 FAX signals (IP network using NGN), the multi-function device 110 is connected to the LAN_I / F. In this case, in the connection path from the multi-function device 10 to the multi-function device 110, T.P. Communication is performed by a 38 FAX signal. In addition, the multi-function device 110 is T.264. In the case of supporting 30 FAX signal (public switched telephone network (PSTN)), the multi-function device 110 is connected to the TEL_I / F. In this case, the connection path from the multi-function device 10 to the home gateway 130 is T.D. The communication is performed by the 38 FAX signal, and the connection path between the home gateway 130 and the multi-function device 110 is T.38. Communication is performed by a 30 FAX signal. In this case, various signals (a DIS signal, an RNR signal, an RR signal, an MCF signal, etc.) are communicated between the multi-function device 10 and the multi-function device 110 via the home gateway 130. The home gateway 130 may include a VoIP (voice over IP) gateway function, a user / terminal authentication function, and the like in addition to a normal router function.

  T. T. Compared to multi-function devices that support 38 FAX signals, A multi-function device supporting 30 FAX signals has a lower data processing capability. This is because T.W. Compared to the communication speed of a communication line (IP network using NGN) in which 38 FAX signals are used, Since the communication speed of the communication line (PSTN) using the 30 FAX signal is slower, Compared to devices that support 38 FAX signals, This is because a 30 FAX signal compatible device has a lower data processing capability (eg, a smaller amount of installed memory). Therefore, T.W. Compared to devices that support 38 FAX signals, A device compatible with the 30 FAX signal is more likely to have a data communication stop period DT1 described later. T. T. The communication speed of the multi-function device corresponding to the 30 FAX signal is, for example, in the range of 33.6 kbps to 2.4 kbps.

(Configuration of multi-function device 10)
The configuration of the multi-function device 10 will be described. The multi-function device 110 has the same configuration as the multi-function device 10. The multi-function device 10 has multiple functions such as a print function, a scanner function, a copy function, an e-mail transmission / reception function, an IPFAX function, and a telephone function. The multi-function device 10 includes a display unit 12, an operation unit 14, a network I / F (interface) 16, a scan execution unit 18, a print execution unit 20, and a control unit 22. Each of the above parts 12 to 22 is connected to the bus line 24. The display unit 12 is a display for displaying various information. The operation unit 14 includes a plurality of keys. The user can input various instructions to the multi-function device 10 by operating the operation unit 14. The network I / F 16 is connected to the LAN 6. The scan execution unit 18 includes a scan mechanism such as a CIS or a CCD, and generates image data by scanning a scan target. The print execution unit 20 includes a printing mechanism such as an inkjet head method or a laser method, and performs printing in accordance with an instruction from the control unit 22.

  The control unit 22 includes a CPU 30 and a memory 32. The memory 32 stores a program 34, a bandwidth billing information table 36, and a parameter group 38. The CPU 30 executes processing according to the program 34 in the memory 32.

  FIG. 9 shows an example of the bandwidth accounting information table 36. The bandwidth billing information table 36 includes a bandwidth 60 (for example, “2.6 Mbps˜”), a transmission speed 61 (for example, “5.0 MB / second”), a billing time 62 (for example, “180 (s)”), a billing 63 (for example, “105 yen”) is stored. The band 60 is a band in which the multi-function device 10 can communicate. In the example of FIG. 9, the band 60 includes five bands (“2.6 Mbps˜”, “1 Mbps˜2.6 Mbps”, “512 kbps˜1 Mbps”, “64 kbps˜512 kbps”, “0 kbps˜64 kbps”). Exists. The multi-function device 10 performs FAX data communication according to any of the five bands 60. Each band has a different size of data that can be communicated per unit time (1 second). For example, the band “256 kbps (kilobit per second)” means that data of 256 kb (kilobit) can be communicated per second. The larger the size of data that can be communicated per second, the faster the communication speed.

  The billing time 62 is a fixed time that is a billing target when the time billing method is adopted. In the time billing method, billing for the next billing time 62 is added each time billing time 62 (for example, 180 (s)) elapses. The billing 63 is a communication fee per billing time 62 required for communication according to the band 60. As shown in the bandwidth billing information table 36, the billing amount of the billing 63 increases as the bandwidth 60 increases (the communication speed increases). From the bandwidth billing information table 36, for example, when the multi-function device 10 performs communication according to the bandwidth 60 = “2.6 Mbps˜”, it is understood that a communication fee of 105 yen is required every 180 seconds. The bandwidth accounting information table 36 may be stored in advance in the memory 32 by the vendor of the multi-function device 10 before shipping the multi-function device 10.

  The parameter group 38 stores various types of information necessary when the multi-function device 10 performs FAX data communication according to each band. Specifically, the parameter group 38 includes a use candidate band, a transmission mode, normal band information, minimum band information, T.P. 38 corresponding flag, etc. are stored. The use candidate band is a band that is a candidate for a band used for transmission of FAX data. There may be a plurality of use candidate bands. The transmission mode includes “normal band transmission mode” and “low band transmission mode”. The normal band transmission mode is a mode used during a period in which the communication destination device can receive FAX data (not busy). The low-band transmission mode is a mode used during a period in which the communication destination device cannot receive FAX data (busy state). The normal band information is information indicating a band (normal band) used in the normal band transmission mode. The minimum bandwidth information is information indicating a bandwidth (minimum bandwidth) used in the low bandwidth transmission mode. The communication speed of the normal band is faster than the communication speed of the lowest band. T. T. et al. 38 flag indicates that the communication destination device is T.38. This is information indicating whether or not it corresponds to the 38 FAX signal (NGN). The parameter group 38 may be stored in advance in the memory 32 by the vendor of the multi-function device 10 before shipping the multi-function device 10.

(Configuration of SIP server 120)
The configuration of the SIP server 120 will be described. For each of the multi-function devices 10 and 110, the SIP server 120 stores the IP address of the multi-function device and the SIP URI of the multi-function device in association with each other. The SIP server 120 establishes a communication session between the multi-function device 10 and the multi-function device 110 using SIP (Session Initiation Protocol). That is, for example, various commands for establishing a communication session for executing IPFAX transmission processing between the multi-function device 10 and the multi-function device 110 are transmitted via the SIP server 120.

(IPFAX transmission processing)
Next, the IPFAX transmission process will be described with reference to FIG. Hereinafter, the contents of the IPFAX transmission process will be described by taking as an example the case where the multi-function device 10 transmits FAX data to the multi-function device 110 that is a communication destination device.

  The flow in FIG. 2 is a flow executed while the power of the multi-function device 10 is turned on. The CPU 30 monitors the execution of the IPFAX transmission operation (S11). The user of the multi-function device 10 can set an original on an unillustrated automatic document feeder and execute an IPFAX transmission operation (eg, pressing a start button after dial input) using the operation unit 14 in that state. it can. The IPFAX transmission operation includes an operation of inputting the SIP URI of the multi-function device 110 that is a FAX transmission destination. When the IPFAX transmission operation is performed (S11: YES), the CPU 30 proceeds to S13.

  In S13, the CPU 30 executes a document reading process. In S15, the CPU 30 executes line connection processing. In S17, the CPU 30 executes a FAX transmission process. In S19, the CPU 30 executes line disconnection processing. Thereby, the IPFAX transmission process is completed. Hereinafter, each process of S13 to S15 will be described.

(Original reading process)
The document reading process (S13) will be described with reference to FIG. In S111, the CPU 30 causes the scan execution unit 18 to scan the document set on the automatic document feeder. As a result, the scan execution unit 18 generates scan data. The CPU 30 stores the scan data generated by the scan execution unit 18 in the memory 32. In S <b> 113, the CPU 30 acquires the scan data stored in the memory 32, performs encoding (compression) processing, generates FAX data, and stores it in the memory 32. Examples of methods used for encoding FAX data include the JBIG method, MMR method, MR method, and MH method in the case of monochrome. In the case of color, there is a JPEG encoding method. Then, the process proceeds to line connection processing (S15).

(Line connection processing)
The contents of the line connection process (S15) will be described with reference to FIG. In S211, the CPU 30 sets the use candidate band in the INVITE message. Specifically, a bandwidth is requested by describing a bandwidth to be used in SDP (Session Description Protocol) in kbps units. SDP is a protocol for specifying the type of media (such as audio or video), the protocol used to carry the media, the port number to be used, and the like. FIG. 10 shows an example of the SDP of the INVITE message. As shown in the area A1, by describing the band 60 to be used as “b = AS: 64”, “b = AS: 512”, “b = AS: 1024”, “0 kbps to 64 kbps”, “64 kbps to Each band 60 of “512 kbps” and “512 kbps to 1 Mbps” can be requested as a use candidate band. Further, of the use candidate bands, a band that can be supported by the multi-function device 110 is notified from the multi-function device 110 by 200 OK.

  In S213, the CPU 30 transmits an INVITE message to the SIP server 120 using the SIP URI acquired in S11 (FIG. 2) as a transmission destination. The SIP server 120 transfers the INVITE message to the multi-function device 110. When the multi-function device 110 receives the INVITE message, the multi-function device 110 transmits 200 OK to the SIP server 120. The SIP server 120 transfers 200 OK to the multi-function device 10.

  In S <b> 215, the CPU 30 monitors whether 200 OK has been received from the multi-function device 110 via the SIP server 120 after transmitting the INVITE message. If not received (S215: NO), the process returns to S215 and waits. If received (S215: YES), the process proceeds to S219.

  In S219, the CPU 30 sets a normal band and a minimum band. Specifically, the 200 OK received in S215 is analyzed. In S211, the bandwidth that can be supported by the multi-function device 110 is extracted from the usage candidate bandwidths requested using the INVITE message. Of the extracted bands, the band with the maximum communication speed is set as the normal band, and the band with the minimum communication speed is set as the minimum band. In S <b> 221, the CPU 30 stores the normal band information regarding the normal band and the minimum band information regarding the minimum band in the parameter group 38 of the memory 32.

  In S223, the CPU 30 transmits an ACK to the SIP server 120 using the SIP URI acquired in S11 (FIG. 2) as a transmission destination. The SIP server 120 transfers ACK to the multi-function device 110. The multi-function device 110 receives the ACK. Thereby, a communication session is established between the multi-function device 10 and the multi-function device 110. When the communication session is established, charging is started. In this embodiment, the SIP server 120 functions as a billing server. Specifically, when a communication session is established in S223, the SIP server 120 starts measuring communication time.

  In S225, the CPU 30 sets the transmission mode to “normal band transmission mode”. In addition, the CPU 30 sets the network I / F 16 so as to perform communication using the band 60 set as the normal band. Then, the process proceeds to FAX transmission processing (S17 in FIG. 2).

(FAX transmission processing)
The FAX transmission process (S17) will be described with reference to FIG. The FAX transmission process is a process for transmitting FAX data to the multi-function device 110 via the IP network 4. In S <b> 302, the CPU 30 determines whether a DIS signal is received from the multi-function device 110. The DIS signal is the first message and describes the function (size, color, encoding method, resolution, presence / absence of T.38, etc.) of the responding side (multifunction device 110). If not received (S302: NO), the process returns to S302 and waits. If received (S302: YES), the process proceeds to S306.

  In S <b> 306, the CPU 30 determines that the multi-function device 110, which is a communication destination device, is T.264. It is determined whether or not a 38 standard FAX signal is supported. This determination is made based on whether or not the “IP recognition T.38 mode facsimile operation” (bit 123) information included in the DIS signal received in S302 is ON. The multi-function device 110 is T.D. 38 is not supported (S306: NO), the process proceeds to S308, and the CPU 30 determines the T.38. The 38 corresponding flag is set to “not supported”. On the other hand, T.W. 38 (S306: YES), the process proceeds to S310, and the CPU 30 executes the T.38. 38 The correspondence flag is set to “correspondence”.

  In S <b> 313, the CPU 30 sends a DCS signal to the multi-function device 110. The DCS signal is a signal for defining transmission parameters and informing the format of data to be actually transmitted. In S <b> 315, the CPU 30 determines whether a CFR signal has been received from the multi-function device 110. The CFR signal is a signal notifying that the DCS signal has been received. If not received (S315: NO), the process returns to S315 and waits. If received (S315: YES), the process proceeds to S317.

  In S317, the CPU 30 sends the partial FAX data to the multi-function device 110 using the normal band. The partial FAX data is data corresponding to one block among the FAX data divided into a plurality of blocks.

  In S319, the CPU 30 determines whether there is untransmitted FAX data. When it exists (S319: YES), it progresses to S331. In S331, the CPU 30 determines whether transmission of the currently transmitted page is completed. If not completed (S331: NO), the process proceeds to S333, and the CPU 30 sends a PPS (Partial Page Signal) -NULL signal to the multi-function device 110. On the other hand, when the transmission of the currently transmitted page is completed (S331: YES), the process proceeds to S335, and the CPU 30 sends a PPS-MPS (Multi Page Signal) signal to the multi-function device 110. In step S338, the CPU 30 executes MCF / RNR reception processing. Then, the process returns to S317.

  On the other hand, if it is determined in S319 that there is no untransmitted FAX data (S319: NO), the process proceeds to S351. In S <b> 351, the CPU 30 sends a PPS-EOP signal to the multi-function device 110. The PPS-EOP signal is a message indicating the end of FAX transmission. In S353, the CPU 30 executes MCF / RNR reception processing. In S <b> 355, the CPU 30 sends a DCN signal to the multi-function device 110. The DCN signal is a signal for informing a connection release message. Then, the FAX transmission process is terminated, and the process proceeds to the line disconnection process (S19 in FIG. 2).

(MCF / RNR reception processing)
The MCF / RNR reception process executed in S338 and S353 will be described using the flow of FIG. In S <b> 410, the CPU 30 determines whether an MCF signal has been received from the multi-function device 110. The MCF signal is a signal for notifying that the partial FAX data has been received. When the MCF signal is received (S410: YES), the process proceeds to S412. In S <b> 412, the CPU 30 determines whether or not the transmission mode stored in the parameter group 38 of the memory 32 is set to “low-band transmission mode”. If the transmission mode is not set to “low bandwidth transmission mode” (S412: NO), the MCF / RNR reception process is terminated, and if it is set (S412: YES), the process proceeds to S414. In S414, the CPU 30 executes an UPDATE process. The contents of the UPDATE process will be described later.

  In S410, when the MCF signal is not received (S410: NO), the process proceeds to S420. In S <b> 420, the CPU 30 determines whether an RNR signal has been received from the multi-function device 110. If not received (S420: NO), the process proceeds to S428, and if received (S420: YES), the process proceeds to S422.

  In S <b> 422, the CPU 30 executes the T.D. stored in the parameter group 38 of the memory 32. The setting contents of the 38 corresponding flag are determined. T. T. et al. When the 38 correspondence flag is set to “corresponding” (S422: corresponding), the process proceeds to S428, and when it is set to “non-corresponding” (S422: not corresponding), the process proceeds to S424.

  In S424, the CPU 30 determines whether or not the transmission mode stored in the parameter group 38 of the memory 32 is set to the “normal band transmission mode”. If the “normal band transmission mode” is not set (S424: NO), the process proceeds to S428, and if it is set (S424: YES), the process proceeds to S426. In S426, the CPU 30 executes an UPDATE process. The contents of the UPDATE process will be described later.

  In S <b> 428, the CPU 30 sends an RR signal to the multi-function device 110. As a result, it is possible to inquire the multi-function device 110 as to whether or not transmission of FAX data can be resumed. Then, the process returns to S410.

(UPDATE processing)
The UPDATE process executed in S414 and S426 will be described using the flow of FIG. In S502, the CPU 30 determines the setting content of the transmission mode. When the transmission mode is set to “normal band transmission mode” (S502: normal band transmission mode), the process proceeds to S504.

  In S504, the CPU 30 reads the minimum bandwidth information from the parameter group 38 and sets it in the UPDATE message. The UPDATE message is information for changing various communication settings, and is information that can be output in parallel with FAX data. Note that the setting method for the UPDATE message for the lowest bandwidth is the same as the setting method for the INVITE message for the use candidate bandwidth described in S211 (FIG. 4), and thus detailed description thereof is omitted here. In S506, the CPU 30 sets the transmission mode to the “low bandwidth transmission mode”. Further, the CPU 30 sets the network I / F 16 so as to perform communication using the band 60 set as the minimum band. Then, the process proceeds to S513.

  On the other hand, if it is determined in S502 that the transmission mode is set to “low-band transmission mode” (S502: low-band transmission mode), the process proceeds to S508. In S508, the CPU 30 reads the normal band information from the parameter group 38 and sets it in the UPDATE message. In S510, the CPU 30 sets the transmission mode to “normal band transmission mode”. In addition, the CPU 30 sets the network I / F 16 so as to perform communication using the band 60 set as the normal band. Then, the process proceeds to S513.

  In S <b> 513, the CPU 30 sends an UPDATE message to the SIP server 120. The SIP server 120 transfers the UPDATE message to the multi-function device 110. Upon receiving the UPDATE message, the multi-function device 110 transmits 200OK to the SIP server 120. The SIP server 120 transfers 200 OK to the multi-function device 10.

  In S515, the CPU 30 monitors whether 200 OK has been received from the SIP server 120 or not. If not received (S515: NO), the process returns to S515 and waits. If received (S515: YES), the UPDATE process is terminated.

(Line disconnect processing)
The line disconnection process (S19) will be described with reference to FIG. In S611, the CPU 30 sends a BYE signal to the SIP server 120. The BYE signal is a command for ending a communication session established between the multi-function device 10 and the multi-function device 110.

  When receiving the BYE, the SIP server 120 ends the charging process and transfers the BYE to the multi-function device 110. When the SIP server 120 finishes the accounting process, the SIP server 120 finishes measuring the communication time required for communication between the multi-function device 10 and the multi-function device 110. When receiving the BYE, the multi-function device 110 transmits 200OK to the SIP server 120. The SIP server 120 transfers 200 OK to the multi-function device 10. In S617, the CPU 30 monitors whether 200 OK is received from the SIP server 120 or not. If not received (S617: NO), the process returns to S617 and waits. If received (S617: YES), the communication session between the multi-function device 10 and the multi-function device 110 ends. Thereby, the IPFAX transmission process is completed.

(Specific example of operation)
A specific example of the operation of the communication system 2 according to the present embodiment will be described with reference to the sequence diagrams of FIGS. 11 and 12. 11 and 12, as an example, a case will be described in which the use candidate bands are “0 kbps to 64 kbps”, “64 kbps to 512 kbps”, and “512 kbps to 1 Mbps”. Further, a case will be described in which the bands that can be supported by the multi-function device 110 are “0 kbps to 64 kbps” and “64 kbps to 512 kbps”. In addition, the multi-function device 110 is T.264. A case in which the multi-function device 110 is not compatible with the 38 FAX signal and is connected to the TEL_I / F of the home gateway 130 will be described. In this case, the multi-function device 110 communicates various signals (such as a DIS signal or an MCF signal) with the multi-function device 10 via the home gateway 130. Further, a case will be described in which the processing capability of the multi-function device 110 is reduced during the period T2 in FIG. 11 to be in a busy state, and the multi-function device 110 returns to the normal state in the period T3 in FIG.

  When the IPFAX transmission operation is executed (S11: YES), the document reading process (S13) is executed. Next, line connection processing (S15) is started. Use candidate bands = “0 kbps to 64 kbps”, “64 kbps to 512 kbps”, “512 kbps to 1 Mbps” are set in the INVITE message (S211), and the INVITE message is sent to the SIP server 120 (S213). When 200 OK is received from the home gateway 130 via the SIP server 120 (S215: YES), it is found that the bandwidths that the home gateway 130 can handle are “0 kbps to 64 kbps” and “64 kbps to 512 kbps”. Accordingly, the band with the maximum communication speed (“64 kbps to 512 kbps”) is set as the normal band, and the band with the minimum communication speed (“0 kbps to 64 kbps”) is set as the minimum band (S219). Then, by transmitting ACK to the SIP server 120, a communication session is established between the multi-function device 10 and the home gateway 130 (S223). Also, the transmission mode is set to “normal band transmission mode” (S225).

  Next, FAX transmission processing (S17) is started. An operation in the period T1 in FIG. 11 will be described. When the DIS signal is received from the multi-function device 110 (S302: YES), the multi-function device 110 receives the T.D. 38 is not compatible with the 38 FAX signal (S306: NO). The 38 corresponding flag is set to “not supported” (S308). When the DCS signal is transmitted to the multi-function device 110 (S313), the CFR signal is received from the multi-function device 110 (S315: YES). When the partial FAX data is sent to the multi-function device 110 using the normal band (“64 kbps to 512 kbps”) (S317) and the PPS-NULL signal is sent to the multi-function device 110 (S333), the MCF signal is sent to the multi-function device 110. (S410: YES). Since the transmission mode is not set to the “low-band transmission mode” (S412: NO), the transmission of partial FAX data (S317) and the reception of the MCF signal (S410: YES) are repeated.

  An operation in the period T2 in FIG. 11 will be described. If the partial FAX data is sent to the multi-function device 110 using the normal band (S317) and the PPS-NULL signal is sent to the multi-function device 110 (S333), the multi-function device 110 is in a state where it cannot receive the FAX data. The RNR signal is received from the multi-function device 110 (S420: YES). T. T. et al. Since the 38 corresponding flag is set to “not supported” (S422: not supported) and the transmission mode is set to “normal band transmission mode” (S424: YES), the UPDATE process is executed (S426). . Since the transmission mode is set to “normal band transmission mode” (S502: normal band transmission mode), the minimum band information is set to the UPDATE message (S504), and the UPDATE message is sent to the SIP server 120 (S513). In addition, the transmission mode is set to “low bandwidth transmission mode”, and the communication mode is switched to perform communication using the lowest bandwidth (“0 kbps to 64 kbps”) (S506). When 200 OK is received (S515: YES), the UPDATE process is terminated.

  An operation in the period T3 in FIG. 12 will be described. When the RR signal is transmitted to the multi-function device 110 (S428), the RNR signal is received from the multi-function device 110 during a period in which the multi-function device 110 cannot receive FAX data (S420: YES). Then, when the multi-function device 110 can receive FAX data, the MCF signal is received from the multi-function device 110 (S410: YES). The period from the reception of the RNR signal (S420: YES) to the reception of the MCF signal (S410: YES) is the data communication stop period DT1 on the multi-function device 110 side.

  Since the transmission mode is set to “low-band transmission mode” (S412: YES), the UPDATE process is executed (S414). Since the transmission mode is set to “low band transmission mode” (S502: low band transmission mode), the normal band information is set to the UPDATE message (S508), and the UPDATE message is sent to the SIP server 120 (S513). Also, the transmission mode is set to “normal band transmission mode”, and the communication mode is switched to perform communication using the normal band (“64 kbps to 512 kbps”) (S510). When 200 OK is received (S515: YES), the UPDATE process is terminated.

  An operation in the period T4 in FIG. 12 will be described. When the last partial FAX data is sent to the multi-function device 110 using the normal band (S317), since there is no untransmitted FAX data (S319: NO), the PPS-EOP signal is sent to the multi-function device 110. (S351). When the MCF signal is received from the multi-function device 110 (S410: YES), the DCN signal is sent to the multi-function device 110 because the transmission mode is not set to “low band transmission mode” (S412: NO) (S355). .

  Then, the line disconnection process (S19) is executed, and the communication session between the multi-function device 10 and the multi-function device 110 ends.

(effect)
The effects of the multi-function device 10 according to the example described in the first embodiment will be described. In the IP network 4 using the communication fee per charging time 62, the multi-function device 110, which is the communication destination device, is charged even during a period in which the FAX data cannot be received due to a decrease in processing capability (data communication stop period DT1). Therefore, useless charging occurs during the period. In the multi-function device 10 according to the first embodiment, when it is determined that the multi-function device 110 cannot receive FAX data (busy state) (S420: YES), the band to be used is set to the lowest band that is slower than the normal band. Change (S504, S506). As a result, as shown in the bandwidth billing information table 36 in FIG. 9, the billing 63 per billing time 62 is generally reduced in accordance with the slowdown of the bandwidth 60 to be used, so the data communication stop period DT1 It is possible to prevent a situation in which the billing amount during the period becomes higher than necessary.

  In response to receiving the RNR signal (S420: YES), the multi-function device 10 determines that the multi-function device 110, which is the communication destination device, is in a state where it cannot receive FAX data, and immediately reduces the bandwidth used. The bandwidth can be changed (S504, S506). In response to receiving the MCF signal as a response to the RR signal (S428) (S410: YES), the multi-function device 10 returns to the state in which the multi-function device 110, which is the communication destination device, can receive FAX data. It is possible to determine and return the use band to the normal band (S508, S510). As a result, the used bandwidth can be reduced to the lowest bandwidth only during the period in which the multi-function device 110 cannot receive FAX data. Therefore, it is possible to achieve both the prevention of a situation where the billing amount becomes higher than necessary and the reduction of the time required for FAX data communication.

  T. Compared to multi-function devices that support 38 FAX signals, A multi-function device that does not support 38 FAX signals has a lower data processing capacity in many cases, and tends to be in a state where FAX data cannot be received. Therefore, the multi-function device 10 is the same as the multi-function device 110. Only when it is detected that it is incompatible with the 38 FAX signal (S306: NO, S422: incompatible), processing for changing the used band from the normal band to the lowest band is executed. As a result, it is possible to more effectively prevent a situation where the billing amount becomes higher than necessary.

(Second embodiment)
A second embodiment will be described. In the second embodiment, the MCF / RNR reception processing (S338, S353) performed in the first embodiment is partially changed. Specifically, the data communication stop period DT1 (the period from when the RNR signal is received until the MCF signal is received) is measured each time to calculate an average stop period that is an average value of the data communication stop period DT1. In this embodiment, the bandwidth is changed to the lowest bandwidth when the average stop period exceeds the billing time of the normal bandwidth. In the second embodiment, the average stop period is further stored in the parameter group 38 of the memory 32. Since the other configurations and operations of the second embodiment are the same as those of the first embodiment, description thereof is omitted here.

(MCF / RNR reception processing)
The MCF / RNR reception process according to the second embodiment will be described with reference to the flowcharts of FIGS. In S <b> 710, the CPU 30 determines whether an MCF signal has been received from the multi-function device 110. When the MCF signal is received (S710: YES), the process proceeds to S712. In S712, the CPU 30 determines whether or not the data communication suspension period DT1 is being measured. If the measurement is not being performed (S712: NO), the process proceeds to S722. If the measurement is being performed (S712: YES), the process proceeds to S714. In S714, the CPU 30 ends the measurement of the data communication stop period DT1.

  In S <b> 716, the CPU 30 determines whether or not the average stop period is stored in the parameter group 38 of the memory 32. If it is not stored (S716: NO), it is determined that this is the first measurement, and the process proceeds to S718. In S718, the CPU 30 stores the data communication stop period DT1 measured this time in the memory 32 as an average stop period. If the average stop period is stored (S716: YES), the process proceeds to S720, and the CPU 30 updates the average stop period using the data communication stop period DT1 measured this time.

  In S722, the CPU 30 determines whether or not the transmission mode is set to the “low bandwidth transmission mode”. If the transmission mode is not set to “low bandwidth transmission mode” (S722: NO), the MCF / RNR reception process is terminated, and if it is set (S722: YES), the process proceeds to S724. In S724, the CPU 30 executes an UPDATE process.

  If the MCF signal is not received in S710 (S710: NO), the process proceeds to S730 (FIG. 14). In S730, the CPU 30 determines whether an RNR signal is received from the multi-function device 110 or not. If not received (S730: NO), the process proceeds to S746, and if received (S730: YES), the process proceeds to S732.

  In S732, the CPU 30 determines whether or not the transmission mode is set to “normal band transmission mode”. When the “normal band transmission mode” is not set (S732: NO), the process proceeds to S746, and when it is set (S732: YES), the process proceeds to S734. In S734, the CPU 30 determines whether or not the data communication suspension period DT1 is being measured. If the measurement is being performed (S734: YES), the process proceeds to S738. If the measurement is not being performed (S734: NO), the process proceeds to S736. In S736, the CPU 30 starts measuring the data communication stop period DT1.

  In S <b> 738, the CPU 30 determines whether or not the average stop period is stored in the parameter group 38 of the memory 32. If it is not stored (S738: NO), this is the case when the RNR signal is received for the first time. Therefore, it is determined not to execute the band changing process, and the process proceeds to S746. On the other hand, if the average stop period is stored (S738: YES), the process proceeds to S740, and the CPU 30 determines whether or not the average stop period exceeds the billing time 62 of the normal band. If not exceeded (S740: NO), the process proceeds to S746, and if exceeded (S740: YES), the process proceeds to S742 to execute the UPDATE process. In S746, the CPU 30 sends the RR signal to the multi-function device 110. Then, the process returns to S710 (FIG. 13).

  In the example of the bandwidth billing information table 36 shown in FIG. 9, the billing time 62 for the bandwidths “2.6 Mbps˜” and “1 Mbps˜2.6 Mbps” is set to 180 seconds. Then, when the bandwidth of “2.6 Mbps to” or “1 Mbps to 2.6 Mbps” is set to the normal bandwidth, the maximum value of the data communication suspension period DT1 is set to 60 seconds on the IP network 4 side. In step S740, the average suspension period (60 seconds or less) does not exceed the normal bandwidth charging time 62 (180 seconds). Therefore, in this case, since the UPDATE process (S742) is not performed, the normal band is not switched to the lowest band.

(effect)
The effects of the multi-function device 10 according to the description example of the second embodiment described above will be described. The data communication stop period DT1 from the reception of the RNR signal to the reception of the MCF signal is a period in which the multi-function device 110 that is the communication destination device is busy. If the data communication suspension period DT1 exceeds the normal bandwidth billing time 62, the bandwidth is changed from the normal bandwidth to the minimum bandwidth, so that the situation where the billing amount becomes higher than necessary can be reliably prevented. is there. Therefore, in the multi-function device 10 according to the second embodiment, the band change is performed only when the average value (average stop period) of the data communication stop period DT1 exceeds the charging time 62 of the normal band (S740: YES). Therefore, it is possible to prevent a situation where useless bandwidth change processing is executed.

  Further, the multi-function device 10 determines whether or not the bandwidth change process can be performed using the average stop period. Thereby, even when an abnormality occurs such as when the data communication stop period DT1 becomes extremely long or short, it is possible to reliably determine whether or not the band change process can be executed.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

(Modification)
In this embodiment, the multi-function device 110 that is the communication destination device is the T.264. The case where the use band is changed from the normal band to the lowest band only when it is detected that the 38 FAX signal is not supported (S306: NO, S422: not supported) is not limited to this form. The destination device is T. Regardless of whether or not it corresponds to the 38 FAX signal, the use band may be changed. In this case, the steps of S306, S308, and S310 may be omitted in the flow of FIG. 5, and the step of S422 may be omitted in the flow of FIG.

  The multi-function device 110 is T.D. In the case of supporting the 38 FAX signal, the multi-function device 110 may be directly connected to the LAN 8 without going through the home gateway 130. In this case, in the connection path from the multi-function device 10 to the multi-function device 110, T.P. Communication is performed by a 38 FAX signal. In addition, communication of various signals (such as a DIS signal or an MCF signal) is directly performed between the multi-function device 10 and the multi-function device 110.

  The minimum bandwidth set in S219 is not limited to the bandwidth with the lowest communication speed among the bandwidths that the multi-function device 110 can handle. If the billing amount per unit time is a band that is cheaper than the normal band, any band may be set as the minimum band.

  The normal band set in S219 is not limited to the band with the maximum communication speed among the bands that the multi-function device 110 can handle. For example, one of the bands that can be supported by the multi-function device 110 may be selected as the normal band based on the size of FAX data to be transmitted.

  In S740 of the second embodiment, the value used when determining whether or not to execute the band change process is not limited to the average stop period. For example, the previous data communication stop period DT1 may be stored in the memory 32, and the band may be changed when the previous data communication stop period DT1 exceeds the charging time 62 of the normal band.

  In the present embodiment, the case where the multi-function device 10 executes the FAX transmission process for the multi-function device 110 has been described as an example. However, the present technology can be applied to various types of data transmission processing (for example, electronic mail transmission processing).

  The contents stored in the bandwidth billing information table 36 (FIG. 9) described in the present embodiment are merely examples. Therefore, the number of bands 60, the band 60, the transmission speed 61, and the like are not limited to these values.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The IP network 4 is an example of a bandwidth securing network. The charging time 62 is an example of a charging unit time. The multi-function device 110 is an example of a communication destination device. The normal band is an example of the first band. The CPU 30 that executes S317 is an example of a first transmission unit. The PPS signal is an example of a first signal. The CPU 30 that executes S333 is an example of a second transmission unit. The RNR signal is an example of a second signal. The lowest band is an example of the second band. The CPU 30 that executes S504 is an example of a bandwidth changing unit. The RR signal is an example of a third signal. The CPU 30 that executes S428 is an example of a third transmission unit. The MCF signal is an example of a fourth signal. The DIS signal is an example of a specific signal. The data communication stop period DT1 is an example of a first period.

  2: Communication system, 4: IP network, 10: Multi-function device, 110: Multi-function device, 120: SIP server, 62: Billing time, DT1: Data communication stop period

Claims (5)

A communication device that is connected to a bandwidth reservation type network and performs data communication with a communication destination device according to any of a plurality of bands having different communication speeds and different communication charges per charging unit time,
First transmission means for transmitting data according to a predetermined first band;
Second transmission means for transmitting a first signal indicating that the data has been transmitted in accordance with the first band;
A second signal indicating that the communication destination device is busy as a response to the first signal when the communication destination device receives a specific signal indicating that the communication destination device is not compatible with the bandwidth reservation type network. The bandwidth changing means for stopping the transmission of data by the first transmission means and changing the bandwidth to be used to a second bandwidth slower than the first bandwidth,
Third transmission means for transmitting a third signal for inquiring whether or not the communication destination device is busy according to the second band;
A communication apparatus comprising: The band changing means includes
In response to receiving the fourth signal indicating that the communication destination device is not busy as a response to the third signal, the band is returned to the first band, and the first transmission means is configured to follow the first band. The communication apparatus according to claim 1, wherein transmission of data is resumed. The band changing means includes
When the first period from the reception of the second signal to the reception of the fourth signal exceeds the charging unit time of the first band, the band is changed from the first band to the second band. The communication device according to claim 2, wherein the communication device is changed. The bandwidth changing means, the communication device according to any one of claims 1 to 3, characterized in that the communication speed among the plurality of bands uses a minimum bandwidth as said second zone. A program for a communication device connected to a bandwidth-reserved network and performing data communication with a communication destination device according to one of a plurality of bands having different communication speeds and different communication charges per charging unit time Because
First transmission means for transmitting data to the transmission unit according to a predetermined first band;
Second transmission means for causing the transmission unit to transmit a first signal indicating that the data has been transmitted according to the first band;
A second signal indicating that the communication destination device is busy as a response to the first signal when the communication destination device receives a specific signal indicating that the communication destination device is not compatible with the bandwidth reservation type network. Band changing means for stopping transmission of data by the first transmitting means and changing a band to be used to a second band that is slower than the first band on the condition that it is received;
Third transmission means for causing the transmission unit to transmit a third signal for inquiring whether or not the communication destination device is busy according to the second band;
That causes a computer mounted on the communication device to function.

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