JP3977160B2 - Network facsimile machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a network facsimile apparatus connected to a global network via a router apparatus having a NAT function.
[0002]
[Prior art]
In recent years, ITU-T recommendation T.I. With the establishment of 37, Internet-compatible facsimile apparatuses that convert a facsimile image into an electronic mail format that is generally exchanged over the Internet and transmit / receive the facsimile image have begun to spread.
[0003]
Also, in April 1999, the T.C. packetized on a packet network such as the Internet. ITU-T recommendation T.30 for exchanging 30 signals (group 3 facsimile transmission procedure signals). 38 was enacted. This T.W. By using the 38 communication technology, it is possible to exchange capabilities (with respect to FAX) between terminals and guarantee real-time communication.
[0004]
T. ITU-T recommendation H.38 regarding call control of 38 terminals. 225.0. This recommendation H. 225.0 opens a call control channel using TCP port 1720 assigned as a well-known port, exchanges SETUP / CONNECT messages at the start of communication, and transmits a facsimile communication protocol (T.30 signal) and Two data channels (unidirectional channels) for transmitting and receiving facsimile image information are established.
[0005]
Then, according to “T.38 Implementers' Guide” issued by ITU-T in 2000, data transmission in the upstream direction from the transmission side to the reception side using one data channel (bidirectional channel) And a communication mode that can simultaneously transfer data in the downstream direction from the receiving side to the transmitting side.
[0006]
On the other hand, a communication infrastructure for high-speed communication represented by ADSL, CATV, or ISDN is being prepared. When ADSL, CATV, or ISDN is used, an ADSL router, CATV router, or ISDN router is connected to the local area network, and the local area network is connected via these ADSL router, CATV router, or ISDN router. In many cases, a connection form in which a communication terminal connected to the Internet is connected to the Internet is employed.
[0007]
Usually, an ADSL router, a CATV router, an ISDN router, or the like uses a technology called NAT (Network Address Translation; refer to RFC1631) in order to compensate for a shortage of the absolute number of IP addresses. This NAT function allows a plurality of communication terminals connected inside the local area network to be locally used by sharing one global address for a plurality of communication terminals connected inside the local network. This is a communication function for enabling communication with other communication terminals on the Internet outside the area network.
[0008]
Here, the ADSL router, CATV router, or ISDN router (referred to as “NAT box” from this point of view) that realizes the NAT function does not overlap with the globally assigned IP address. The private address (10.0.0.0-10.255.255.255.255 (class A) or 172.16.0.0-172) defined by RFC 1597 (Address Allocation for Private Internets) in the local network. .31.255.255 (Class B) or 192.168.0.0-192.168.255.255 (Class C)) is commonly used.
[0009]
[Problems to be solved by the invention]
However, the communication method using the NAT box has a disadvantage that the connection from the local network to the global network can be established, but the connection from the global network to the local network cannot be performed.
[0010]
SUMMARY An advantage of some aspects of the invention is that it provides a network facsimile apparatus that can appropriately exchange image information with the outside of a local area network.
[0011]
[Means for Solving the Problems]
The present invention relates to a bi-directional channel communication means for performing bidirectional communication with a communication partner terminal using a single communication channel in a network facsimile apparatus connected to a global network via a router having a NAT function. Control means for controlling switching between the bi-directional channel communication means and the unidirectional channel communication means for communicating with the communication partner terminal using two communication channels And a first judging means for judging whether the IP address of the terminal is a global IP address or a private IP address. When the facsimile communication is performed with the communication protocol of 38, when the first determination means determines that it is a private IP address, the communication is switched to communicate with the bi-directional channel communication means, and the first determination means When it is determined that the address is a global IP address, switching control is performed so that communication is performed by the unidirectional channel communication means.
[0012]
The communication partner terminal further includes second determination means for determining whether the IP address of the communication partner terminal is the same network segment as that of the own terminal, and when the second determination means determines that the IP address is the same network segment, The control means controls switching so that communication is performed by the unidirectional channel communication means.
[0013]
The communication partner terminal further comprises third determination means for determining whether communication with the bi-directional channel communication means is requested, and the third determination means determines that no request is made. When this is done, the control means ends the transmission error.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0017]
FIG. 1 shows a network system according to an embodiment of the present invention.
[0018]
In the figure, a plurality of workstation devices WS1 to WSn and two network facsimile devices FX1 and FX2 are connected to the local area network LAN and connected to the Internet via a router device RT. . Therefore, the workstation devices WS1 to WSn and the network facsimile devices FX1 and FX2 can exchange data with other appropriate terminal devices via the Internet.
[0019]
The router device RT functions as a NAT box having a NAT function. In this case, the workstation apparatuses WS1 to WSn inside the local area network LAN and the network facsimile apparatuses FX1 and FX2 have private IP addresses (for example, 192.168.0.0-192.168.255. An arbitrary value of 255) is set.
[0020]
When the network facsimile apparatuses FX1 and FX2 are installed outside the local area network LAN, a global IP address is assigned to the network facsimile apparatuses FX1 and FX2.
[0021]
In the workstation devices WS1 to WSn, various programs such as facsimile application software for creating and displaying facsimile image information and various software for exchanging various data via the local area network LAN. Has been introduced and is used by specific users. Here, the specific user may be one or a plurality of users.
[0022]
The network facsimile machines FX1 and FX2 are ITU-T recommendation T.264. 37 communication function (e-mail type facsimile communication function) and ITU-T recommendation T.37. 38 Facsimile communication function (real-time facsimile communication function) and Facsimile communication that connects to the analog public line network PSTN and performs image information transmission by the group 3 facsimile transmission procedure using this public network as a transmission path It has a function.
[0023]
FIG. 2 shows a configuration example of the network facsimile apparatus FX (FX1, FX2).
[0024]
In the figure, a system control unit 1 performs various control processes such as a control process of each part of the network facsimile apparatus FX and a facsimile transmission control procedure process. The system memory 2 is executed by the system control unit 1. The control processing program and various data necessary for executing the processing program are stored, and the work area of the system control unit 1 is configured. The parameter memory 3 is unique to the network facsimile apparatus FX. The clock circuit 4 outputs current time information.
[0025]
The scanner 5 is for reading a document image at a predetermined resolution, the plotter 6 is for recording and outputting an image at a predetermined resolution, and the operation display unit 7 operates the network facsimile apparatus FX. It consists of various operation keys and various displays.
[0026]
The encoding / decoding unit 8 encodes and compresses the image signal, and also decodes the encoded and compressed image information into the original image signal. The image storage device 9 performs encoding and compression. This is for storing a large number of image information in the selected state.
[0027]
The group 3 facsimile modem 10 is for realizing the modem function of the group 3 facsimile, and is a low-speed modem function (V.21 modem) for exchanging transmission procedure signals, and mainly for exchanging image information. A high-speed modem function (V.17 modem, V.34 modem, V.29 modem, V.27ter modem, etc.) is provided.
[0028]
The network control apparatus 11 is for connecting the network facsimile apparatus FX to the analog public line network PSTN, and has an automatic outgoing / incoming function.
[0029]
The local area network interface circuit 12 is for connecting the network facsimile machine FX to the local area network LAN. 37 The communication control unit 13 receives the ITU-T recommendation T.36 via the local area network LAN. 37 for realizing an electronic mail type facsimile communication function compliant with T.37. The communication control unit 14 transmits the ITU-T recommendation T.38 via the local area network LAN. This is to realize a real-time facsimile communication function conforming to No.38.
[0030]
The system control unit 1, system memory 2, parameter memory 3, clock circuit 4, scanner 5, plotter 6, operation display unit 7, encoding / decoding unit 8, image storage device 9, group 3 facsimile modem 10, network Control device 11, T.M. 37 communication control unit 13, and T.37. The 38 communication control unit 14 is connected to the internal bus 15, and data exchange between these elements is mainly performed via the internal bus 15.
[0031]
Data exchange between the network control device 11 and the group 3 facsimile modem 10 is performed directly.
[0032]
Here, in the present embodiment, basically, data exchange between terminals connected to the local area network LAN is a transmission protocol up to a transport layer called TCP / IP, and more. This is performed by applying a combination with a higher layer communication protocol (so-called protocol suite). For example, in the exchange of e-mail data, a communication protocol called SMTP (Simple Mail Transfer Protocol) is applied as an upper layer communication protocol.
[0033]
In addition, as a protocol that each terminal applies to the mail server for confirmation of receipt of an e-mail addressed to the user or an acquisition request, a so-called POP (Post Office Protocol) can be applied.
[0034]
Further, communication protocols such as TCP / IP, SMTP, POP, and data format and data structure of e-mail are defined by RFC documents issued from IETF. For example, RFC 793, IP RFC 793, SMTP RFC 821, and e-mail formats are defined in RFC 822, RFC 1521, and RFC 1522 (MIME (Multipurpose Mail Extension) format), respectively.
[0035]
Then, the network facsimile apparatuses FX1 and FX2 transfer the read document image to other group 3 facsimile apparatuses via the public network PSTN or workstation apparatuses WS1 to WSn via the local area network LAN (or the Internet). Image information received from another group 3 facsimile apparatus via the analog public line network PSTN is transmitted to the user corresponding to the subaddress designated at that time. A transfer service for transferring image information received by e-mail or image information received (by e-mail) from the workstation WS of the local area network LAN to the group 3 facsimile apparatus of the designated analog public line network PSTN. It has a function, and the like.
[0036]
In addition, for the e-mail received to the terminal itself, the image information arranged in the text information is taken out and recorded and output.
[0037]
Here, the facsimile image information is binary data, and the e-mail cannot include binary data directly. Therefore, a predetermined conversion method (for example, Base64 encoding method) is applied to read the readable information (7-bit information). The character code is included in the email. Such a format of e-mail text information is called MIME format.
[0038]
An example of an e-mail used when transmitting facsimile image information in this way is shown in FIG.
[0039]
This e-mail is an e-mail in a multi-part MIME format having a plurality of body parts. The e-mail transmission date (“Date” field), the destination e-mail address (“To” field), and the source e-mail address (“From” "Field)", a text header part for carrying text data, and a binary part part for carrying facsimile image information. In the binary part part, facsimile image information is MIME. MIME encoded data obtained by the conversion is arranged.
[0040]
The facsimile image information carried by e-mail is obtained by compressing the original image data by MH encoding and converting it into the TIFF-F format. Therefore, as MIME encoded data, this TIFF-F data is used. Are converted to MIME.
[0041]
Here, in the TIFF-F format, image data of a plurality of pages can be collected as one file, so that data of one transmission image information file consisting of a plurality of pages can be arranged in one binary part portion. .
[0042]
4 shows ITU-T recommendation T.30. 3 shows an example of a data transmission procedure between network facsimile apparatuses FX1 and FX2 (T.38 terminal apparatus) when the 38 communication function is used.
[0043]
First, the originating T.P. The 38 terminal device is called the receiving side T.38. 38 establishes a call control TCP channel for the terminal device 38, The terminal device 38 receives the packet SETUP for call connection on the called side T.38. 38 to the terminal device.
[0044]
Callee T. The 38 terminal device is the calling side T.38. When the packet SETUP is received from the terminal device 38, the packet CONNECT is transmitted to the originating T.P. 38 responds to the terminal device, whereby the originating T.P. 38 terminal equipment and called side T.38. A call is established with 38 terminal devices. Further, the exchange mode (TCP mode or UDP mode) to be used and the port number to be used are set by exchanging the packet SETUP and the packet CONNECT.
[0045]
Next, the originating T.P. The 38 terminal device establishes a data UDP channel from the calling side to the called side, and at the called side T.38 terminal device. The 38 terminal device establishes a data UDP channel from the callee side to the caller side. 38 terminal equipment and called side T.38. 38 terminal devices, the recommended T.38 using the two established UDP channels for data. T. 38 procedure was followed. 38 session data exchange is started, and image information communication operation is executed.
[0046]
When the image information communication is completed, the calling side T.P. The 38 terminal device receives the packet RELEASECOMP on the receiving side T.38. 38 to the terminal device. 38 terminal equipment and called side T.38. The data communication operation with the 38 terminal device ends.
[0047]
FIG. 5 shows ITU-T recommendation T.30. In the procedure of 38, the above-mentioned T.I. An example of a transmission procedure performed in 38 sessions is shown. In FIG. 38 terminals and the receiving side T.38. The 38 terminals correspond to the network facsimile machines FX1 and FX2 of this embodiment.
[0048]
First, the transmission side transmits a connection request packet to the reception side to request connection, and the reception side that receives the connection request packet transmits a connection confirmation packet to the transmission side to confirm call connection.
[0049]
As a result, a communication path between the transmission side and the reception side is established. A signal (T30IND: CED) corresponding to a predetermined tone signal CED (called station identification signal) of 30 procedures is transmitted to the transmitting side, and a signal corresponding to a flag signal (T30IND: Flag) is followed by group 3 facsimile transmission. It is a procedure signal, a signal NSF for notifying its own optional transmission function, a signal CSI for notifying its own identification signal, and a signal for notifying its standard transmission function A signal (V21HDLC: NSF / CSI / DIS) corresponding to each DIS is sequentially transmitted to the transmission side.
[0050]
Thereby, the transmitting side knows the identification signal and the transmission function of the receiving side, and based on the notified transmission function, sets the transmission function and modem speed to be used at that time. Next, the transmitting side is a group 3 facsimile transmission procedure signal following the signal (T30IND: Flags) corresponding to the flag signal, and notifies the signal TSI for notifying its own terminal identification signal and the transmission function to be used. The signal (V21HDLC: TSI / DCS) respectively corresponding to the signal DCS for transmission is transmitted to the receiving side.
[0051]
Thereby, when the receiving side receives the signal (V21HDLC: TSI / DCS), it acquires the identification information of the counterpart terminal (transmitting side) and the transmission function used at that time.
[0052]
The receiving side is a group 3 facsimile transmission procedure signal following the signal (T30IND: Flags) corresponding to the flag signal, and a signal (V21HDLC: CFR) corresponding to the signal CFR for notifying that the reception preparation is completed. ) To the sender.
[0053]
In this way, when the image information is ready to be transmitted, the transmitting side transmits a signal (T30IND: Speed) corresponding to a training signal for modem retraining to the receiving side, and then transmits The image data of the image information is divided into a plurality of pieces, and the divided image information is transmitted to the receiving side as packet data (indicated as “V.17 non ECM: Image data” in FIG. 4).
[0054]
When the transmission of the image information is completed, a signal (T30IND: Flags) corresponding to the flag signal is transmitted to the receiving side, and the signal EOP corresponding to the group 3 facsimile procedure signal, which indicates that the image information transmission is terminated, is supported. A signal (V21HDLC: EOP) is transmitted to the receiving side.
[0055]
On the other hand, when the receiving side receives the signal (T30IND: Speed), the receiving side shifts to preparation for receiving the image information. When the receiving side receives the packet carrying the image information, the divided image information included in the received information is sequentially taken out and the combined image information is received. And the image information is stored in the image storage device 9. In this case, since the signal (V21HDLC: EOP) is received as the post-transmission signal after receiving the image information, it is confirmed that the reception of the image information is completed.
[0056]
If the reception result of the image information at that time is good, the reception side is a group 3 facsimile procedure signal following the signal corresponding to the flag signal (T30IND: Flags), and the reception of the image information is normally completed. A signal (V21HDLC: EOP) corresponding to the signal MCF indicating the fact is transmitted to the transmission side.
[0057]
Thereby, the transmission side recognizes that the image information has been normally received on the reception side. After this, the transmission side receives the signal (V21HDLC: DCN) corresponding to the signal DCN for instructing line restoration, which is a group 3 facsimile procedure signal, following the signal corresponding to the flag signal (T30IND: Flags). Send to.
[0058]
When the receiving side receives the signal (T30IND: Flags) and the signal (V21HDLC: DCN), the image information receiving operation ends.
[0059]
Finally, the transmitting side sends a disconnection request packet requesting that the communication path is disconnected to the receiving side, and when the receiving side receives the disconnection request packet, it indicates that the communication path has been confirmed to be disconnected. A confirmation packet is sent to the transmission side, and a series of communication operations is completed.
[0060]
In this way, image information is transmitted from the transmission side to the reception side.
[0061]
Here, the signal (T30IND: “signal name”) in FIG. 30 is a signal for notifying the detection of a tonal signal according to ITU-T Recommendation T.30. 30 is a signal for carrying a binary signal according to 30. Also, “V.21”, ITU-T recommendation V.21. 21 indicates that the signal is carried by the modem, and “HDLC” indicates that the signal is an HDLC frame.
[0062]
The transmission procedure shown in FIG. Recommendation T.30 corresponding to 30 standard procedures. 38 procedures. When applying 30 optional procedures (for example, file transfer mode, etc.), the corresponding recommendation T.30. 38 procedures are executed. At this time, the same type of signal as that in FIG. 5 is applied to the signal exchanged between the transmission side and the reception side.
[0063]
ITU-T recommendation T.I. 38, as described above, two data, that is, an upstream data channel from the transmission side to the reception side (unidirectional channel; UDP mode or TCP mode) and a downstream data channel from the reception side to the transmission side. Establish a unidirectional channel mode for establishing a channel and one data channel (bidirectional channel; TCP mode), and use this one bidirectional channel to transmit from the sender to the receiver. And two bi-directional channel modes in which data transfer in the downstream direction from the receiving side to the transmitting side is simultaneously performed can be selectively set. Of these, the unidirectional channel mode is preferentially used.
[0064]
Here, the network facsimile apparatus FX1 connected to the local area network LAN and other T.F. T.38 terminal device 38, the network facsimile machine FX1 and the T.38 communication are used. The 38 terminal devices exchange packets via the router device RT.
[0065]
As described above, the router device RT functions as a NAT box and applies the NAT function, and as shown in FIG. Since the packet is exchanged with the 38 terminal devices, the following problems occur.
[0066]
In FIG. The IP address set in the 38 terminal is “P1” of the private IP address. The IP address set in the router RT is the private IP address “P2” at the connection end of the local area network LAN and the global IP address “G2” at the connection end of the Internet. Also, the callee side The IP address set for the 38 terminal is the global IP address “G2”. “SrcIP” indicates the IP address on the packet transmission side, and “dstIP” indicates the IP address on the packet reception side.
[0067]
That is, in the TCP / IP communication using the NAT function, the network facsimile apparatus FX1 installed in the local area network LAN is changed to the T.264 installed in the global network (Internet). When sending an IP packet to the 38 terminal, the src address information (srcIP) is converted from the local IP address (P1) to the global IP address (G2) by the NAT function of the router device RT located in the middle.
[0068]
T. on the global side The 38 terminal returns a response packet to the NAT box, and the NAT box (router device RT) receiving the response packet recognizes that it is a response of the packet sent by itself and receives the dst address (G2). Communication is performed by converting the IP address of the appropriate local terminal (in this case, “P1”) and passing it.
[0069]
However, T. In 38 communications, two unidirectional channels are required, and the address information is determined by the application layer located above the TCP / IP protocol.
[0070]
Therefore, the called side T.P. The 38 terminal tries to establish a downlink data channel for the designated local address (P1). However, since the IP address does not exist in the global network, the packet has no place to go and disappears.
[0071]
As a simple idea, the callee side T.W. It seems that the problem can be solved by establishing a downstream data channel for the IP address (G2) of the NAT box (router device RT) that is the packet transmission source without using the address specified at the application level by the 38 terminals. Certainly, in this method, the T. Packets from 38 terminals reach the NAT box. However, in the current NAT function, even if such a packet is received, it is transmitted to any T.D. I cannot understand if it is addressed to 38 terminals (network facsimile machines FX1, FX2).
[0072]
For this reason, the packet is transmitted to the local T.P. The 38 terminals (network facsimile machines FX1, FX2) are not reached, and the downlink data channel is not established.
[0073]
In order to avoid such a situation, a data channel in the bi-directional channel mode may be secured instead of the unidirectional channel mode.
[0074]
In this case, the originating T.P. Only 38 terminals make a data channel establishment request. Therefore, the called side T.P. 38 terminal does not request establishment of a data channel, and as a result, a data channel is properly established. 38 communication operations can be performed.
[0075]
FIG. 38 shows an example of processing executed when the start of communication is designated.
[0076]
First, the IP address set in the own terminal is checked (process 101), and it is checked whether it is the value of the private IP address (decision 102).
[0077]
When the result of the decision 102 is YES, bi-directional that simultaneously performs upstream data transfer from the transmission side to the reception side and downstream data transfer from the reception side to the transmission side using one data channel. • Use channel mode.
[0078]
Therefore, a call setup message SETUP having a content including a value for requesting the bi-directional channel mode is transmitted (process 103). When a response message CONNECT is received from the counterpart terminal (process 104), the contents of the response message CONNECT are checked to determine whether the counterpart terminal has requested a data channel in the bidirectional channel mode (decision 105).
[0079]
When the result of determination 105 is YES, a data channel in the bi-directional channel mode is established (process 106), and the subsequent T.P. 30 procedures are started (process 107).
[0080]
If the other terminal does not request a data channel in the bi-directional channel mode and the result of determination 105 is NO, the transmission operation is terminated at that point. In this case, the transmission operation ends with an error.
[0081]
On the other hand, when the value of the IP address set in the own terminal is a global IP address and the result of determination 102 is NO, the call setup message SETUP includes a value requesting the unidirectional channel mode. The content is transmitted (process 108).
[0082]
When the response message CONNECT is received from the partner terminal (process 109), a data channel in the unidirectional channel mode is established (process 110), and the process proceeds to process 107. Start 30 procedures.
[0083]
In this way, in this embodiment, the value of the IP address set in the own terminal is checked, and if the value is the value of the private IP address, the T.P. Since the bi-directional channel mode is set as the data channel required during 38 communication, appropriate data communication can be performed.
[0084]
FIG. The other example of the process performed when the start of 38 communication is designated is shown.
[0085]
First, the IP address set in the own terminal is checked (process 201), and it is checked whether it is the value of the private IP address (decision 202).
[0086]
When the result of the determination 202 is YES, bi-directional that simultaneously performs upstream data transfer from the transmitting side to the receiving side and downstream data transfer from the receiving side to the transmitting side using one data channel. • Use channel mode.
[0087]
Therefore, a call setup message SETUP having a content including a value for requesting the bi-directional channel mode is transmitted (process 203). When the response message CONNECT is received from the counterpart terminal (process 204), the contents of the response message CONNECT are checked to check whether the counterpart terminal has requested a data channel in the bidirectional channel mode (decision 205).
[0088]
When the result of determination 205 is YES, a data channel in the bi-directional channel mode is established (process 206), and the subsequent T.P. 30 procedures are started (process 207).
[0089]
On the other hand, when the value of the IP address set in the own terminal is a global IP address and the result of determination 202 is NO, the call setup message SETUP includes a value requesting the unidirectional channel mode. The content is transmitted (process 208).
[0090]
When the response message CONNECT is received from the partner terminal (process 209), a data channel in the unidirectional channel mode is established (process 210), and the process proceeds to process 207. Start 30 procedures.
[0091]
In addition, when the call setup message SETUP includes a value including a value requesting the bi-directional channel mode, the other terminal does not request a data channel in the bi-directional channel mode. When the result of determination 205 is NO, the transmission operation is temporarily stopped at that time (processing 211), and the process proceeds to processing 208 to perform communication operation in the unidirectional channel mode.
[0092]
In this way, in this embodiment, the value of the IP address set in the own terminal is checked, and if the value is the value of the private IP address, the T.P. Since the bi-directional channel mode is set as the data channel required during 38 communication, appropriate data communication can be performed. In this case, when the counterpart terminal requests the unidirectional channel mode, the transmission operation is switched to the unidirectional channel mode, so that an appropriate transmission operation is possible.
[0093]
FIG. 38 shows still another example of processing executed when the start of communication is designated.
[0094]
First, the IP address of the partner terminal is checked (process 301), and it is checked whether it is the same network segment value as the own terminal (decision 302).
[0095]
When the result of determination 302 is NO, the IP address set in the own terminal is further checked (process 303), and it is checked whether it is the value of the private IP address (determination 304).
[0096]
When the result of the determination 304 is YES, bi-directional that simultaneously performs upstream data transfer from the transmission side to the reception side and downlink data transmission from the reception side to the transmission side using one data channel. • Use channel mode.
[0097]
Therefore, a call setup message SETUP having a content including a value for requesting the bi-directional channel mode is transmitted (process 305). When a response message CONNECT is received from the counterpart terminal (process 306), the contents of the response message CONNECT are checked to determine whether the counterpart terminal has requested a data channel in the bidirectional channel mode (decision 307).
[0098]
When the result of determination 307 is YES, a data channel in the bi-directional channel mode is established (process 308), and the subsequent T.P. 30 procedures are started (process 309).
[0099]
On the other hand, when the value of the IP address set in the own terminal is a global IP address and the result of determination 304 is NO, the call setup message SETUP includes a value requesting the unidirectional channel mode. The content is transmitted (process 310).
[0100]
When the response message CONNECT is received from the partner terminal (process 311), a data channel in the unidirectional channel mode is established (process 312), and the process proceeds to process 309. Start 30 procedures.
[0101]
In addition, when the call setup message SETUP includes a value including a value requesting the bi-directional channel mode, the other terminal does not request a data channel in the bi-directional channel mode. When the result of determination 307 is NO, the transmission operation is terminated at that time. In this case, the transmission operation ends with an error.
[0102]
On the other hand, when the IP address of the partner terminal is not included in the same network segment and the result of determination 302 is YES, the process proceeds to process 310 to perform a transmission operation in the unidirectional channel mode.
[0103]
Whether or not the IP address is included in the same network segment can be determined, for example, by examining whether or not the IP address is a value to which the same terminal can be applied.
[0104]
In this way, in this embodiment, the value of the IP address of the partner terminal is checked, and if the value is not included in the same network segment, the value of the IP address set in the own terminal is further determined. If the value is the value of the private IP address, T. Since the bi-directional channel mode is set as the data channel required during 38 communication, appropriate data communication can be performed. In other cases, the communication operation in the unidirectional channel mode, which is the default communication mode, is performed, so that an appropriate transmission operation can be performed.
[0105]
FIG. 38 shows still another example of processing executed when the start of communication is designated.
[0106]
First, the IP address of the partner terminal is checked (process 401), and it is checked whether it is the same network segment value as the own terminal (decision 402).
[0107]
When the result of determination 402 is NO, the IP address set in the own terminal is further checked (process 403), and it is checked whether it is the value of the private IP address (determination 404).
[0108]
When the result of determination 404 is YES, bi-directional that simultaneously performs upstream data transfer from the transmission side to the reception side and downlink data transmission from the reception side to the transmission side using one data channel. • Use channel mode.
[0109]
Therefore, a call setup message SETUP having a content including a value for requesting the bi-directional channel mode is transmitted (process 405). When a response message CONNECT is received from the counterpart terminal (process 406), the contents of the response message CONNECT are checked to check whether the counterpart terminal has requested a data channel in the bi-directional channel mode (decision 407).
[0110]
When the result of determination 407 is YES, a data channel in the bi-directional channel mode is established (process 408), and the subsequent T.P. 30 procedures are started (process 409).
[0111]
On the other hand, when the value of the IP address set in the own terminal is a global IP address and the result of determination 404 is NO, the call setup message SETUP includes a value requesting the unidirectional channel mode. The content is transmitted (process 410).
[0112]
When the response message CONNECT is received from the partner terminal (process 411), a data channel in the unidirectional channel mode is established (process 412), and the process proceeds to process 409. Start 30 procedures.
[0113]
On the other hand, if the IP address of the partner terminal is not included in the same network segment and the result of determination 402 is YES, the process proceeds to process 410, and a transmission operation in the unidirectional channel mode is performed.
[0114]
In addition, when the call setup message SETUP includes a value including a value requesting the bi-directional channel mode, the other terminal does not request a data channel in the bi-directional channel mode. When the result of determination 407 is NO, the transmission operation is temporarily stopped at that time (processing 413), and the process proceeds to processing 410 to perform communication operation in the unidirectional channel mode.
[0115]
Whether or not the IP address is included in the same network segment can be determined, for example, by examining whether or not the IP address is a value to which the same terminal can be applied.
[0116]
In this way, in this embodiment, the value of the IP address of the partner terminal is checked, and if the value is not included in the same network segment, the value of the IP address set in the own terminal is further determined. If the value is the value of the private IP address, T. Since the bi-directional channel mode is set as the data channel required during 38 communication, appropriate data communication can be performed. In other cases, the communication operation in the unidirectional channel mode, which is the default communication mode, is performed, so that an appropriate transmission operation can be performed.
[0117]
By the way, in the above-described embodiment, T.I. When T.38 transmission operation is specified, the T.38 transmission operation is always performed. 38, the image information is transmitted by performing the communication operation. Even in the case of switching to the 37 communication operation, the object of image information transmission can be achieved.
[0118]
In this case, for the IP address designated by the user, T.P. 37 It is necessary to set an e-mail address used for communication operation. For this purpose, for example, an address conversion table as shown in FIG. 11A is created and stored. This address translation table is composed of a plurality of address translation information. The address translation information includes a destination name, T.264, as shown in FIG. 37 address (e-mail address) This is a set of 38 addresses (IP addresses).
[0119]
In this case, FIG. 38 shows still another example of processing executed when the start of communication is designated.
[0120]
First, the IP address of the partner terminal is checked (process 501), and it is checked whether it is a value of the same network segment as that of the own terminal (decision 502).
[0121]
When the result of determination 502 is NO, the IP address set in the own terminal is further checked (process 503), and it is checked whether it is the value of the private IP address (determination 504).
[0122]
When the result of determination 504 is YES, the address conversion table described above is referred to and the T.T. 38 addresses 37 address (process 505) and the communication mode is changed to T.37. The communication mode is switched to the 37 communication mode (process 506).
[0123]
Then, an e-mail containing image information is created (process 507), and the e-mail is transmitted to an appropriate mail server (process 508).
[0124]
On the other hand, when the value of the IP address set in the own terminal is a global IP address and the result of determination 504 is NO, the call setup message SETUP includes a value requesting the unidirectional channel mode. The content is transmitted (process 510).
[0125]
When a response message CONNECT is received from the partner terminal (process 511), a data channel in the unidirectional channel mode is established (process 512). 30 procedures are started (process 513).
[0126]
On the other hand, when the IP address of the partner terminal is not included in the same network segment and the result of determination 502 is YES, the process proceeds to processing 510 to perform a transmission operation in the unidirectional channel mode.
[0127]
Whether or not the IP address is included in the same network segment can be determined, for example, by examining whether or not the IP address is a value to which the same terminal can be applied.
[0128]
FIGS. 38 shows another example of processing executed when the start of communication is designated.
[0129]
First, the IP address of the partner terminal is checked (process 601), and it is checked whether it is a value of the same network segment as that of the own terminal (decision 602).
[0130]
When the result of determination 602 is NO, the IP address set in the own terminal is further checked (process 603), and it is checked whether it is the value of the private IP address (determination 604).
[0131]
When the result of determination 604 is YES, bi-directional is performed using one data channel to simultaneously perform uplink data transfer from the transmission side to the reception side and downlink data transfer from the reception side to the transmission side. • Use channel mode.
[0132]
Therefore, a call setup message SETUP including a content including a value for requesting the bi-directional channel mode is transmitted (process 605). When a response message CONNECT is received from the counterpart terminal (process 606), the contents of the response message CONNECT are checked to check whether the counterpart terminal has requested a data channel in the bi-directional channel mode (decision 607).
[0133]
When the result of determination 607 is YES, a data channel in the bi-directional channel mode is established (process 608), and the subsequent T.P. 30 procedures are started (process 609).
[0134]
On the other hand, when the value of the IP address set in the own terminal is a global IP address and the result of determination 604 is NO, the call setup message SETUP includes a value requesting the unidirectional channel mode. The content is transmitted (process 610).
[0135]
When the response message CONNECT is received from the partner terminal (process 611), a unidirectional channel mode data channel is established (process 612), and the process proceeds to process 609. Start 30 procedures.
[0136]
On the other hand, when the IP address of the partner terminal is not included in the same network segment and the result of determination 602 is YES, the process proceeds to process 610 to perform a transmission operation in the unidirectional channel mode.
[0137]
In addition, when the call setup message SETUP includes a value including a value requesting the bi-directional channel mode, the other terminal does not request a data channel in the bi-directional channel mode. When the result of determination 607 is NO, T.W. 37 Switch to communication operation.
[0138]
That is, referring to the address conversion table described above, the T.D. 38 addresses 37 address (process 615) and the communication mode is changed to T.37. The communication mode is switched to the 37 communication mode (process 616).
[0139]
Then, an e-mail containing the image information is created (process 617), and the e-mail is transmitted to an appropriate mail server (process 618).
[0140]
Whether or not the IP address is included in the same network segment can be determined, for example, by examining whether or not the IP address is a value to which the same terminal can be applied.
[0141]
In this way, in this embodiment, the value of the IP address of the partner terminal is checked, and if the value is not included in the same network segment, the value of the IP address set in the own terminal is further determined. If the value is the value of the private IP address, T. Since the bi-directional channel mode is set as the data channel required during 38 communication, appropriate data communication can be performed. If the terminal of the terminal requests the bi-directional channel mode but the partner terminal specifies the uni-directional channel mode, T.I. Since the operation is switched to the 37 communication operation, appropriate image information communication can be performed.
[0142]
FIG. 15 shows an example of processing executed when the e-mail reception processing is activated.
[0143]
First, the IP address set in the own terminal is checked (process 701), and it is checked whether it is the value of the private IP address (decision 702).
[0144]
When the result of the determination 702 is YES, a POP mode that is a client-type e-mail reception process is set as a process for acquiring an e-mail (process 703). Specifically, a POP process for connecting to a POP server and receiving an e-mail is started.
[0145]
Then, it waits for a waiting time for acquiring an e-mail (process 704), connects to the POP server, inquires whether an e-mail addressed to the own terminal has been received (process 705), and sends an e-mail addressed to the own terminal. If a mail has been received (the result of determination 706 is YES), an electronic mail is acquired from the POP server (process 707), and the process returns to process 704. If the result of determination 706 is NO, the process returns to step 704 and waits until the next e-mail acquisition timing.
[0146]
On the other hand, when the IP address set in the own terminal is not the value of the private IP address and the result of determination 702 is NO, the SMTP mode which is a server-type e-mail receiving process is performed as a process for obtaining e-mail. Is set (process 710). Specifically, an SMTP server process for transferring electronic mail according to the transfer path is started.
[0147]
In this SMTP mode, the occurrence of a mail event is monitored (NO loop of decision 711). If a mail event occurs and the result of decision 711 is YES, an e-mail is acquired (step 712), and the process returns to decision 711.
[0148]
In this way, in this embodiment, when the value of the IP address set in the own terminal is a private IP address, the e-mail is acquired in the POP mode. Can be received.
[0149]
In this embodiment, the POP mode is used as the client-type e-mail reception process, but other client-type e-mail reception processes (for example, IMAP4) can be applied.
[0150]
【The invention's effect】
As described above, according to the present invention, the value of the IP address set in the own terminal is checked, and when the value is the value of the private IP address, the T.P. Since the bi-directional channel mode is set as the data channel required at the time of 38 communication, an effect that appropriate data communication can be performed is obtained.
[0151]
Further, when the value of the IP address set in the own terminal is checked and the value is the value of the private IP address, the T.P. Since the bi-directional channel mode is set as the data channel required at the time of 38 communication, appropriate data communication can be performed, and in this case, when the partner terminal requests the unidirectional channel mode. Is switched to the transmission operation in the unidirectional channel mode, so that an appropriate transmission operation can be obtained.
[0152]
Further, when the value of the IP address of the partner terminal is checked and the value is not included in the same network segment, the value of the IP address set in the own terminal is further checked and the value is the private IP. In the case of an address value, T.P. Since the bi-directional channel mode is set as the data channel required at the time of 38 communication, appropriate data communication can be performed. In other cases, the unidirectional channel which is the default communication mode. Since the mode communication operation is performed, an effect of enabling an appropriate transmission operation is also obtained.
[0153]
Further, when the value of the IP address of the partner terminal is checked and the value is not included in the same network segment, the value of the IP address set in the own terminal is further checked and the value is the private IP. In the case of an address value, T.P. Since the bi-directional channel mode is set as the data channel required at the time of 38 communication, appropriate data communication can be performed. In other cases, the unidirectional channel which is the default communication mode. Since the mode communication operation is performed, an effect of enabling an appropriate transmission operation is also obtained.
[0154]
Further, when the value of the IP address set in the own terminal is checked and the value is the value of the private IP address, the T.P. 38 communication mode to T.38. Since the transmission operation is switched to the 37 communication mode, it is possible to perform appropriate image information transmission.
[0155]
Further, when the value of the IP address of the partner terminal is checked and the value is not included in the same network segment, the value of the IP address set in the own terminal is further checked and the value is the private IP. In the case of an address value, T.P. Since the bi-directional channel mode is set as the data channel required at the time of 38 communication, an appropriate data communication can be performed, and the host terminal requested the bi-directional channel mode. If the terminal has designated the unidirectional channel mode, the Since switching to the 37 communication operation is performed, there is also an effect that appropriate image information communication can be performed.
[0156]
In addition, when the value of the IP address set in the own terminal is a private IP address, the e-mail is acquired in the POP mode, so that the e-mail can be received appropriately. Also get.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a network system according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration example of a network facsimile apparatus FX (FX1, FX2).
FIG. 3 is a schematic diagram showing an example of electronic mail used when transmitting facsimile image information.
FIG. 4 is an ITU-T recommendation T.30. The time chart which showed an example of the data transmission procedure between the network facsimile apparatuses FX1 and FX2 (T.38 terminal device) in the case of using 38 communication function.
FIG. In the procedure of 38. The time chart which showed an example of the transmission procedure performed in 38 sessions.
FIG. 6 shows a network facsimile apparatus FX1 and T.I. The time chart for demonstrating exchange of the packet between 38 terminal devices.
FIG. The flowchart which showed an example of the process performed when the start of 38 communication is designated.
FIG. The flowchart which showed the other example of the process performed when the start of 38 communication is designated.
FIG. 38 is a flowchart showing yet another example of processing executed when the start of communication is designated.
FIG. 38 is a flowchart showing still another example of processing executed when the start of communication is designated.
FIG. 11 is a schematic diagram illustrating an example of an address conversion table.
FIG. 38 is a flowchart showing still another example of processing executed when the start of communication is designated.
FIG. The flowchart which showed another example of the process performed when the start of 38 communication is designated.
FIG. 38 is a flowchart showing another example of processing executed when the start of communication is designated (continuation).
FIG. 15 is a flowchart showing an example of processing executed when starting up an e-mail receiving process;
[Explanation of symbols]
FX1, FX2 network facsimile machine
RT router device

Claims (3)

In a network facsimile machine connected to a global network via a router device having a NAT function,
  Bi-directional channel communication means for performing two-way communication with one communication channel for communication with a communication partner terminal;
  Unidirectional channel communication means for performing communication with a communication partner terminal using two communication channels;
  Control means for switching control between the bi-directional channel communication means and the unidirectional channel communication means;
  First determining means for determining whether the IP address of the terminal is a global IP address or a private IP address;
  The control means includes
  ITU-T recommendation When performing facsimile communication with 38 communication protocols,
  When the first determining means determines that the private IP address is used,
  Switching to communicate with the bi-directional channel communication means,
  A network facsimile apparatus, wherein when the first determination means determines that the address is a global IP address, switching control is performed so that communication is performed by the unidirectional channel communication means. A second determining means for determining whether the IP address of the communication partner terminal is the same network segment value as the own terminal;
  When it is determined by the second determination means that they are the same network segment,
  2. The network facsimile apparatus according to claim 1, wherein the control means performs switching control so that communication is performed by the unidirectional channel communication means. Further comprising third determination means for determining whether or not the communication partner terminal is requesting communication by the bi-directional channel communication means;
  When it is determined that the third determination means does not request,
  3. The network facsimile apparatus according to claim 2, wherein the control means ends a transmission error.

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