JP2003158618A - Facsimile gateway, method for controlling the facsimile gateway, and control program for the facsimile gateway - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a facsimile gateway for relaying the ITU-T recommendations T.38 capable of relaying voice communication and other communication data as well as facsimile communication. SOLUTION: The facsimile gateway decides whether it relays facsimile communication or it relays other communications than the facsimile communication thereafter depending on a signal coming from a PSTN side facsimile machine connected via lines 1 to 3 or from an opposite gateway connected through a network card 20. Concerning the communication other than the facsimile communication, the facsimile gateway aims at voice communication or a socket service on an IP connection, in particular, E-mail transmission/reception.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile gateway for performing real-time Internet facsimile communication conforming to ITU-T Recommendation T.38, a control method therefor, and a control program therefor.

[0002]

2. Description of the Related Art The spread of the Internet in recent years has been remarkable, and there have been proposed techniques for applying network communication techniques to facsimiles by various methods.

One of them is ITU-T Recommendation T.38.
There is so-called real-time internet facsimile communication described in. The communication described in the recommendation is
As shown in FIG. 1, the facsimile devices (A, B) 100 and 112 communicate with each other via the facsimile gateways (A, B) 104, 108 connected to the IP network (Internet or intranet) 106.

Facsimile devices (A, B) 100, 11
2 is a facsimile gateway (A, B) 104, 108 via PSTN (general public line) 102, 110.
Connected with. If the facsimile device (A) 100 is the calling side, the facsimile device 100 calls the gateway 104 via the PSTN 102.

Then, TCP (or UDP) / I is provided between the gateway (emittering gateway) 104 and the gateway (receiving gateway) 108.
Form a P connection. The gateway 108 uses the facsimile machine 100 to the gateway 1 in some way.
Based on the telephone number information notified from 04, PSTN11
The facsimile machine (B) 112 is called via 0 to establish the call. After that, the G3 facsimile signal is IFP
According to (Internet facsimile protocol), it is encapsulated in a TCP (or UDP) packet and exchanged.

[0006] The current recommendation T. 38, the facsimile apparatus 11 is added to the (emitter) gateway 104.
Only the method of performing double dialing to notify the telephone number of No. 2 is described (Recommendation T.38, Appendix B.2.1), and the (receiving) gateway 1
The details of the technical specifications for notifying the 08.08 of the telephone number of the facsimile apparatus 112 are not recommended (Recommendation T.38, Appendix B.2.2).

2 and 3 show ITU-T Recommendation T.264. Three
8 shows a state of Internet facsimile communication by 8.

Reference numeral 201 in FIGS. 2 and 3 designates a facsimile apparatus on the transmitting side (here, the calling side) for transmitting an image, and 204 designates a facsimile apparatus on the receiving side, which is the facsimile apparatus 1 in FIG.
Corresponds to either 00 or 112.

Further, reference numeral 202 is an emitting gateway (transmission side gateway), and 203 is a receiving gateway (reception side gateway), which correspond to either of the gateways 104 and 108 in FIG. 1, respectively. These gateway devices can be configured as dedicated facsimile machines with network interfaces and PSTN interfaces, or from computer systems with similar communication interfaces.

Facsimile protocol signals transmitted and received between the transmitting side facsimile apparatus 201 and the emitting gateway 202 and between the receiving side facsimile apparatus 204 and the receiving gateway 203 are exactly the same as those of the normal G3 facsimile protocol as shown in the figure. Yes, these signals follow the IFP as shown in the central portion of FIGS. It is converted into 38 packets and encapsulated in a TCP (or UDP) packet to be exchanged.

T. 38 packets are TYPE and DA
It consists of TA elements. The DATA part is the content of the actual signal, but TYPE has T30IND (T30IND
Indicator), T30_DAT indicating the modulation method of the signal
The signals transmitted as A TYPE and DATA are HDL
HDLC_XX to indicate C format
X, etc. (T.38 Recommendation 7.2).

In this way, even a facsimile machine having only a PSTN interface can communicate with each other via an IP network such as the Internet, and it is expected to reduce costs such as international call charges that have been conventionally required. Yes, in that case, the facsimile machines 100, 11
For 2, a conventional G3 facsimile machine or the like can be used as it is. Moreover, there is a possibility that the telecommunications carrier can be provided with a business opportunity using such a gateway.

ITU-T Recommendation T. 38 is an Internet facsimile machine (IAF) capable of directly transmitting / receiving not only gateways but also packets exchanged between the gateways.
ax device) 112a (FIG. 1) is also described. This Internet facsimile machine 112a is
The IFP packets shown in FIGS. 2 and 3 are directly transmitted / received to perform facsimile communication.

[0014]

[Problems to be Solved by the Invention] Current ITU-T Recommendation T. 38 is a T.I. 30 protocols as TCP (or UD
Only the outline of the technology for relaying over P) / IP connection is defined, and the details of the protocol are not described.

For example, in the configuration in which the facsimile devices are directly connected via the PSTN, the telephone call can be performed without disconnecting the line by operating the "telephone" button. Although the procedure signals are exchanged and the call is started, the recommendation T. 38, the function of the facsimile gateway for shifting to voice communication when the same operation is performed in the client facsimile device is not defined at all.

That is, at present, Recommendation T. Facsimile gateways defined in T.38 are merely T.38. It is a single-function device that relays only 30 protocols on a TCP (or UDP) / IP connection, and cannot be said to sufficiently support the functions required by the user of the client facsimile device.

The object of the present invention is to solve the above problems by
TU-T recommendation T.T. In a facsimile gateway that relays 38 communication, not only facsimile communication but also voice communication and other communication data can be relayed.

[0018]

In order to solve the above problems, according to the present invention, a PSTN is used by using an Internet facsimile protocol compliant with ITU-T Recommendation T.38.
In the facsimile gateway for relaying a facsimile signal between the facsimile device on the side and the gateway of the other side, its control method, and its control program,
According to a signal coming from the STN-side facsimile machine or the partner gateway, a configuration is adopted in which it is determined thereafter whether to relay the facsimile communication or the communication other than the facsimile communication.

Alternatively, the communication other than the facsimile communication is voice communication.

Alternatively, the communication other than the facsimile communication is a socket service on a TCP / IP or UDP / IP connection.

Alternatively, the socket service is a relay of electronic mail according to the SMTP protocol.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows the construction of a facsimile gateway device adopting the present invention. The apparatus of FIG. 4 has a PSTN interface for connecting to a facsimile machine and a network interface for connecting to the Internet (IP network).
The facsimile apparatus on the interface side is an apparatus that communicates according to the G3 facsimile procedure and communicates with the facsimile gateway of the other party via the Internet (IP network). The device of FIG. 4 operates as an emitting gateway or a receiving gateway.

In FIG. 4, reference numeral 2 is an NCU (network control unit), which is used to connect the telephone network to the terminal of the line for use in data communication and to control the connection of the telephone switching network.
It is for switching to a data communication path and for holding a loop. In addition, NCU2
Based on the control from the bus 26, control is performed to open the telephone line 2a (CML off) or connect the telephone line 2a to the facsimile machine side (CML on). The telephone line 2a is open in the normal state.

Reference numeral 6 denotes a hybrid circuit, which separates a transmission system signal and a reception system signal, sends the transmission signal from the addition circuit 12 to the telephone line 2a via the NCU 2, and transmits the signal from the other side. Received via the NCU 2 and sent to the demodulator 8 via the signal line 6a.

Reference numeral 8 indicates ITU-T Recommendation V.34. 8, V.I. Two
1, V.I. 27 ter, V.I. 29, V.I. 17, V.I. It is a modulator / demodulator capable of executing modulation and demodulation based on 34, and each of these transmission modes can be selected by controlling from the bus 26. The modem 8 receives the transmission signal from the bus 26, outputs the modulated data to the signal line 8a, and outputs the modulated data to the signal line 6a.
The received signal output to the above is input and the demodulated data is output to the bus 26.

Reference numeral 10 is a calling circuit, which inputs telephone number information by a signal from the bus 26 and which is connected to the signal line 10a.
The DTMF selection signal is output to. Reference numeral 12 is an adding circuit, which inputs the information of the signal line 8a and the information of the signal line 10a and outputs the addition result to the signal line 12a.

Blocks 2 to 12 are telephone lines 2a.
A line interface (1) 30 for connecting to the (PSTN line 1) is configured. In the present embodiment, in addition to this, the line interface (2) 14 for connecting to the telephone line (PSTN line 2) 14a configured similarly to the line interface (1) 30, and the telephone line (PST).
A line interface (3) 16 for connecting to the N line 3) 16a is provided, and connection control of these line interfaces is executed by the CPU 22 via the bus 26.

Reference numeral 18 denotes a memory circuit, which is composed of a storage element such as a memory (RAM) and serves as a work area, raw information of read image data, or
It is used to store encoded information, and to store received information, decoded information, or the like via the bus 26.

Reference numeral 20 is a network card,
It is connected to the Internet via the signal line 20a.
The network hardware architecture is arbitrary, but the network card 20 is composed of, for example, an Ethernet (trademark) interface card or the like.

Reference numeral 22 denotes a CPU (central processing unit), which controls the entire facsimile gateway, and a facsimile transmission control procedure with the facsimile device.
It also executes communication procedures between gateways. C
The control program of the PU 22 is stored in the ROM 24.
The CPU 22 is connected to the above blocks via a bus 26.

Reference numeral 24 is a ROM, which stores a control program of the CPU 22 for executing communication control described later.

Reference numeral 31 is a voice processing circuit for performing A / D conversion and D / A conversion of a voice signal which will be described later. The audio processing circuit 31 converts the audio signal received from the PSTN output to the signal line 6a into digital audio data, and
The digital voice data received via the network card 20 is converted into an analog voice signal.

Next, the operation of the above configuration will be described. In the gateway of the present invention, Recommendation T. The feature is that not only the facsimile signal is relayed by 38, but also communication other than facsimile can be relayed. That is, in the present invention, when an incoming call arrives from the client facsimile machine via the PSTN, the communication corresponding to the received signal from the client facsimile machine is relayed according to the received signal. Although there are several options for "communication other than facsimile" here, first, the relay of voice communication (telephone) will be described below.

5 to 8 show a control procedure for relaying voice communication (telephone). The illustrated procedure is the CPU 22.
It is stored in the ROM 24 as a control program of.

In FIG. 5, step S0 represents the beginning of the process started upon power-on or reset.

In step S2, the memory 18 is initialized via the bus 26. In step S4, all CMLs (CML1, CML1,
Turn off 2 and 3).

In step S6, it is determined whether or not there is an incoming call from the PSTN, that is, one of the lines 1, 2, and 3. If there is no incoming call, the process proceeds to step S8, and if there is an incoming call from the PSTN, the process proceeds to step S12. Here, for simplification of explanation, it is assumed that all the lines are unused, and when there is an incoming call, the CM of the line 1 is used.
L1 is turned on to accept an incoming call.

In step S8, it is determined whether or not there is a connection request from the partner gateway. The connection request from the partner gateway is transmitted via the network card 20 to the TC.
It arrives in the form of a P (UDP) connection request. If there is no connection request from the partner gateway in step S8, another process is executed in step S10, and the process returns to step S6. If there is a connection request from the other gateway,
Then, the process proceeds to step S34.

When there is an incoming call from the PSTN, in step S12, the CML1 of the line 1 is turned on to accept the incoming call.

In step S14, the destination information about the final partner station is received, and in step S16, the received destination information about the partner station is transmitted to the partner gateway. This destination information is double dialed, that is, the calling station (facsimile device or telephone) who has called this gateway follows the telephone number of this gateway (after a predetermined pause time if necessary) DTMF. It shall be transmitted by a signal or the like.

In step S18, the signal arriving from the calling station is received and its content is analyzed. Step S of FIG.
The determination of 18 determines whether the signal coming from the calling station is simply a facsimile signal or a voice signal. For example, in step S18, CNG (facsimile call)
When a signal is detected and CNG is received, it may be determined that a facsimile signal is received, and when a CNG cannot be detected, a voice signal is received.

If the facsimile signal is not received (the voice signal is received), go to step S20 (FIG. 6).
If a facsimile signal is received, step S
28 (FIG. 7).

In step S20 of FIG. 6, P is transmitted from the calling station.
The audio signal transmitted via the STN is A / D-processed by the audio processing circuit 31 at a predetermined bit rate (for example, 8 kbps).
Convert and send to the other gateway. Further, in step S22, the voice data similarly transmitted through A / D conversion from the partner gateway is received, and the received voice data is D / A converted by the voice processing circuit 31 and transmitted to the calling station.

Note that the steps S20 and S22 are described separately as two steps for easy understanding, but they are originally to be executed as full-duplex communication, and are actually executed simultaneously. To be executed. Note that a technique of relaying a voice signal on a TCP (or UDP) / IP connection is known, and ITU-T Recommendation H.264. 323, R
Since it is described in FC2705, etc., it will not be described in detail here.

In step S24, it is detected whether or not the voice communication is completed by detecting the polarity reversal of the line connected to the CML1. If the call has not ended, the process returns to step S20 to continue the relay process. If the call has ended, the CML1 is turned off in step S26 and the process returns to step S6 (FIG. 5).

On the other hand, when the facsimile signal is received in step S18, the recommendation T.38 is received in step S28 of FIG. T between the other gateway based on 38
The above-mentioned facsimile signal is relayed on the CP (or UDP) / IP connection. In step S32, it is determined whether or not the facsimile communication is completed. If the facsimile communication is completed, the process returns to step S6. If the facsimile communication is not completed, the T.S. 38 Continue the relay process.

If there is a connection request from the partner gateway in step S8, the process proceeds to step S34 in FIG.
The processing after step S34 is performed when the present apparatus described above operates as a "partner gateway".

In step S34, the destination information is received from the partner gateway. This destination information is step S1.
Sent at 6. In step S36, CML1 is turned on, and in step S38, the terminal corresponding to the received destination information is called.

In step S40, it is determined whether the signal coming from the partner gateway is a facsimile signal (received as an IFP packet according to Recommendation T.38) or a digital voice signal. If the signal received from the partner gateway is a voice signal, step S in FIG.
20, S22 is executed, that is, the voice signal is relayed. If the signal received from the partner gateway is a facsimile signal, execute step S28 in FIG.
That is, the recommendation T. 38 relays facsimile communication.

As described above, the facsimile gateway according to the present invention is recommended by T.K. Not only is the facsimile signal relayed by 38, but also voice communication (telephone) can be relayed as communication other than facsimile.

In the above embodiment, the voice communication is based on the T.264 standard. 38
Since it is not necessary to change the facsimile communication of the Internet, the compatibility of the Internet facsimile communication is not impaired, and techniques such as so-called VoIP and IP telephony are known, and voice signals are changed from A / D to D / A. Since many chips and the like are known, they can be easily implemented.

In the above, an example of relaying voice communication (telephone) has been shown, but as communication to be supported as "communication other than facsimile", an IP connection is provided to the communication terminal of the client connecting via PSTN. It is possible to do it. That is, a PPP (point-to-point) connection is provided to the client communication terminal so that it can operate as a so-called IP router (or so-called access server).

Once the IP connection by the PPP connection is established with the client communication terminal,
Any communication provided by the socket service (socket communication) on TCP (UDP) / IP can be supported. TCP (UDP)
/ IP socket services known as well-known ports include SMTP and NNT
Although there are P, HTTP, etc., here, e-mail transmission / reception (SMTP) is considered.

FIG. 9 shows a control procedure for further relaying an E-mail in addition to a facsimile signal and a voice signal. In the case of the embodiment shown in FIG. 9, the gateway has software for establishing a PPP connection with a client connecting via the PSTN installed as a program of the CPU 22. In case of PPP connection, FIG.
The destination information in steps S14 and S16 is not transmitted and received, but instead, the required authentication procedure is executed between the gateway and the client device calling by the LCP procedure included in the PPP protocol, and only when the authentication is successful. A PPP connection is established between this gateway and the calling client device. The client device making a call at this stage can execute all socket communication on TCP (UDP) / IP unless the gateway filters.

The step S52 in FIG. 9 is the step S18 in FIG. 5, and the step S68 is the step S4 in FIG.
It replaces 0.

In step S52, the connection type with the client terminal connected via the PSTN is determined, and in step S68, the connection type with the partner gateway is determined. This connection type judgment is a more general understanding of the above-mentioned judgment of the signal transmitted from the other party (client or gateway). If the other party is transmitting a facsimile signal or a voice signal, it is the same as above. Can be detected. Also, when a PPP connection is established between the client devices that have made a call as described above, the connection type may be determined to be a PPP connection.

If the connection type is voice or facsimile in step S52, step S2 is executed.
Then, the process proceeds to 0 or S28 to relay the voice or facsimile communication as described above.

In step S52, the connection type is P
In the case of PP, email communication is performed in steps S58 and S60 (completion of communication is determined in step S62). Here, the E-mail data is directly exchanged with the PSTN or the other gateway in steps S58 and S60, and the gateway directly executes the function of a so-called SMTP server. Since the destination information is included as the header information of the email, this destination information can be used.

However, it is not essential that the gateway itself has the function of the SMTP server, and of course, it is possible to relay the received mail to another SMTP server. In this case, since the destination information is included as the header information of the E-mail, this destination information can be used and it is not necessary to establish a connection with the partner facsimile gateway.

When the e-mail information is relayed between the two facsimile gateways, some modifications can be considered as the processing executed by the gateway on the receiving side.

One is that the gateway on the receiving side makes a call to the terminal device on the receiving side to establish a PPP connection, and then the E-mail is transferred to the terminal device by using the SMTP procedure. Alternatively, a method may be used in which the terminal device on the receiving side calls the gateway and spools the e-mail data until the e-mail data is downloaded by the POP procedure. The other is that the gateway on the receiving side is connected to the client facsimile machine on the receiving side and the T.I. A configuration is conceivable in which the E-mail information is connected by the 30 protocol, the received e-mail information is converted into an image by using a character generator ROM, etc.

As described above, the facsimile gateway according to the present invention is recommended by T.K. 38 not only relays the facsimile signal by 38, but also provides an IP connection to the client device, and further, TCP (UDP) /
It can support the communications provided by sockets over IP, especially email communications.

The gateway device of this embodiment can be configured as a dedicated facsimile device having a network interface and a PSTN interface, or a computer system having a similar communication interface. The control program of the gateway device according to the present embodiment may be stored in the ROM 24 in advance, or may be supplied to the gateway device via any other computer-readable medium.

[0065]

As is apparent from the above description, according to the present invention, a facsimile signal is relayed between the PSTN-side facsimile device and the partner gateway using the Internet facsimile protocol conforming to ITU-T Recommendation T.38. Facsimile gateway, its control method,
And a control program therefor, in accordance with a signal coming from the PSTN-side facsimile apparatus or the partner gateway, thereafter adopting a configuration for deciding whether to relay facsimile communication or relay communication other than facsimile communication. ITU-T Recommendation T.3. In a facsimile gateway that relays 38 communication, there is an excellent effect that communication data other than facsimile communication can be relayed.

Alternatively, by adopting a configuration in which communication other than the facsimile communication is voice communication,
ITU-T Recommendation T. In a facsimile gateway that relays 38 communication, there is an excellent effect that voice communication can be relayed in addition to facsimile communication.

Alternatively, ITU-T Recommendation T.264 may be adopted by adopting a configuration in which communication other than the facsimile communication is a socket service on a TCP / IP or UDP / IP connection. In a facsimile gateway that relays 38 communications, T
There is an excellent effect that the socket service on the CP / IP or UDP / IP connection can be relayed.

Alternatively, by adopting a configuration in which the socket service is a relay of electronic mail according to the SMTP protocol, ITU-T Recommendation T.264. In the facsimile gateway which relays 38 communication, there is an excellent effect that electronic mail data can be relayed in addition to the facsimile communication.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a facsimile communication system based on ITU-T recommendation T.38.

FIG. 2 is an explanatory diagram showing a state of communication in the configuration of FIG.

FIG. 3 is an explanatory diagram showing a state of communication in the configuration of FIG.

FIG. 4 is a block diagram showing a configuration of a facsimile gateway adopting the present invention.

5 is a flowchart showing a communication control procedure in the configuration of FIG.

FIG. 6 is a flowchart showing a communication control procedure in the configuration of FIG.

7 is a flowchart showing a communication control procedure in the configuration of FIG.

8 is a flowchart showing a communication control procedure in the configuration of FIG.

9 is a flowchart showing a different communication control procedure in the configuration of FIG.

[Explanation of symbols]

2 NCU 6 hybrid circuit 8 modem 10 Calling circuit 12 adder circuit 14 line interface (2) 16 line interface (3) 18 memory 20 network cards 22 CPU 24 ROM 30 line interface (1) 31 Audio processing circuit

Claims (12)

[Claims] 1. A facsimile gateway for relaying a facsimile signal between a PSTN-side facsimile apparatus and a partner gateway using an Internet facsimile protocol conforming to ITU-T Recommendation T.38, wherein the PSTN-side facsimile apparatus or the partner gateway is used. A facsimile gateway characterized by comprising control means for determining whether to relay a facsimile communication or a communication other than a facsimile communication thereafter, according to an incoming signal. 2. The facsimile gateway according to claim 1, wherein the communication other than the facsimile communication is voice communication. 3. The communication other than the facsimile communication is TC
The facsimile gateway according to claim 1, which is a socket service on a P / IP or UDP / IP connection. 4. The facsimile gateway according to claim 3, wherein the socket service is relay of an electronic mail according to the SMTP protocol. 5. A facsimile gateway control method for relaying a facsimile signal between a PSTN-side facsimile apparatus and a partner gateway using an ITU-T Recommendation T.38 compliant Internet facsimile protocol, wherein the PSTN-side facsimile apparatus or the above A method of controlling a facsimile gateway, comprising a control step of determining whether to relay a facsimile communication or a communication other than a facsimile communication thereafter, according to a signal coming from a partner gateway. 6. The method of controlling a facsimile gateway according to claim 5, wherein the communication other than the facsimile communication is voice communication. 7. The communication other than the facsimile communication is TC
The method of controlling a facsimile gateway according to claim 5, wherein the method is a socket service on a P / IP or UDP / IP connection. 8. The method of controlling a facsimile gateway according to claim 7, wherein the socket service is relay of an electronic mail according to the SMTP protocol. 9. A facsimile gateway control program for relaying a facsimile signal between a PSTN-side facsimile apparatus and a partner gateway using an ITU-T Recommendation T.38 compliant Internet facsimile protocol, wherein the PSTN-side facsimile apparatus or the above A control program for a facsimile gateway, which includes a control step of determining whether to relay facsimile communication or to relay communication other than facsimile communication thereafter, according to a signal coming from a partner gateway. 10. The control program for a facsimile gateway according to claim 9, wherein the communication other than the facsimile communication is voice communication. 11. The communication other than the facsimile communication is T
10. The facsimile gateway control program according to claim 9, which is a socket service on a CP / IP or UDP / IP connection. 12. The facsimile gateway control program according to claim 11, wherein the socket service is a relay of an electronic mail according to the SMTP protocol.