KR20040048711A - Method For Controlling FAX Call - Google Patents

Abstract

PURPOSE: A method of controlling a facsimile call is provided to control a facsimile call using Megaco protocol of signaling protocol of an access gateway to enable Internet facsimile service as well as the existing facsimile service. CONSTITUTION: A soft switch grasps the kinds and characteristics of resources supported by an access gateway and prepares a facsimile call(S701). The access gateway detects calling tone(CNG) and called station identification(CED) signals generated by a facsimile terminal and sets a facsimile stream path between corresponding facsimile terminals to attempt a facsimile call(S702). The calling facsimile terminal transmits a call setup signal to the called facsimile terminal and sets up the facsimile call to which the access gateway allocates a resource(S703). The access gateway receives a disconnect message and cancels the allocated resource to release the facsimile call(S704).

Description

How to control fax calls {Method For Controlling FAX Call}

The present invention relates to a facsimile (FAX) call control method, and more particularly, among signaling protocols of an access gateway using a backbone of an IP network as a facsimile service that was available in a PSTN exchange using a conventional circuit network. The present invention relates to a FAX call control method that enables an existing FAX service by controlling a FAX call using the Megaco protocol and accommodates new services such as Internet FAX.

In general, FAX refers to a communication method in which still images such as text, diagrams, and photographs are decomposed into pixels, converted into electric signals, transmitted, and a permanent recording image is obtained at the reception point in the form of an original picture.

Hereinafter, a conventional PSTN based FAX call control system will be described with reference to FIG. 1.

1 is a diagram illustrating a conventional PSTN based FAX call control system.

The conventional PSTN based FAX call control system is composed of an originating FAX terminal 10a, an originating Public Switched Telephone Network (PSTN) exchange 20a, an incoming PSTN exchanger 20b, and an incoming FAX terminal 10b. Enter the desired incoming fax terminal 10b number into the outgoing fax terminal 10a, and according to the entered number, the outgoing PSTN exchange 20a translates the number and then receives the registered subscriber through the incoming PSTN exchange 20b. The FAX call is connected to the FAX terminal 10b, and then a FAX call procedure is performed between the originating FAX terminal 10a and the destination FAX terminal 10b on the connected line.

As described above, the FAX transmission technology of the existing originating PSTN exchanger 20a transmits a FAX stream on a network that is circuit based, and the corresponding FAX is transmitted from the destination PSTN exchanger 20b of the counterpart. The stream is recovered and transmitted to the destination FAX terminal 10b. To this end, the International Telecommunication Union Telecommunication sector (ITU-T) has proposed a call procedure between the originating FAX terminal 10a and the destination FAX terminal 10b. This has been published in the T.30 Protocol Recommendation.

However, as the telecommunication market is becoming more common, the T.38 protocol recommendation of ITU-T has been raised for the purpose of accepting FAX terminals on IP networks.

Hereinafter, a conventional PSTN based (T.30 protocol recommendation) FAX call control method will be described with reference to FIG. 2.

2 is a flowchart illustrating a conventional PSTN based FAX call control procedure.

As shown in FIG. 2, a FAX call control procedure for transmitting a FAX stream from an originating FAX terminal 10a to a destination FAX terminal 10b includes a call establishment process, an image transmission process, and a call release process. It can be divided into three processes of call release.

In the call setup process, the calling FAX terminal 10a presses a counterpart number and transmits a CNG message (CalliNG tone) to the called FAX terminal 10b (S201), whereby the called FAX terminal 10b responds. In response to the reception of the CNG message, a CED message (Called station Identification) is transmitted to the originating FAX terminal 10a (S202).

In the process of transmitting the image, the incoming FAX terminal 10b transmits a DIS message (Digital Identification Signal) containing its capabilities to the originating FAX terminal 10a (S203), and thus the origination. The FAX terminal 10a transmits a TCF message (Training Check Field) to the destination FAX terminal 10b for DCS message (Digital Command Signal Handshake Message) and FAX transmission channel check (S204, S205), and the destination FAX terminal. 10b transmits a CFR message (Confirmation to Receive) to the originating FAX terminal 10a in order to confirm the transmission channel and the capability (S206), and the corresponding originating FAX terminal 10a recalls the FAX page. Transmit to the destination FAX terminal 10b and send an EOP message (End of Procedure) to the destination FAX terminal 10b to indicate completion of the FAX call or end of page transmission (S207, S208), and corresponding destination FAX terminal 10b. ) Sends the first page Transmits a MCF message to indicate that the additional presence of the transfer page ready to receive (Multi Page Signaling) to the calling FAX terminal (10a) (S209).

In the call release process, the called FAX terminal 10b transmits a DCN message to the originating FAX terminal 10a to inform the release of the FAX call (S210).

Hereinafter, a conventional TCP / IP based (T.38 protocol recommendation) FAX call control method will be described with reference to FIG. 3.

3 is a diagram illustrating a conventional TCP / IP based FAX call control system.

If a FAX terminal based on T.30 protocol transmits / receives FAX data via existing network, ITU-T defines the necessary details to realize FOIP (FAX Over Internet Protocol) using TCP / IP network. The protocol is a T.38 protocol. The reason why the FOIP is effective is that the bandwidth required for the FAX transmission in the existing line network is 64Kbps (two-way communication), which is the voice bandwidth, but the maximum bandwidth required for transmitting the FAX stream in the TCP / IP network is 14.4Kbps (one-way communication). )to be.

As shown in FIG. 3, a 60Kbps full duplex is applied between the originating FAX terminal 10a and the FAX Over Packet IWF 30a in a FAX analog form. 14.4 Kbps half duplex (FAX in DigitalForm) between the outgoing FAX over packet interworking unit 30a and the incoming FAX over packet interworking unit 30b and the Frame Relay Internet Protocol network. Half Duplex) is applied, and a 60Kbps full duplex is applied between the called FAX over packet interworking unit 30b and the called FAX terminal 10b in FAX analog form.

Hereinafter, the configuration of the FOIP service of the access gateway will be described with reference to FIG. 4.

4 is a configuration diagram of a FOIP service of a conventional access gateway.

An access gateway is an apparatus for receiving existing FAX data and converting the packet data into packet data for the processing of the FAX over packet. SoftSwitch is present. The relationship between the soft switch and the access gateway is a concept that separates the bearer connection function and the call control function among the roles of the existing PSTN exchanger, thereby performing the actual call processing of the access gateway that accommodates the FOIP function. To be in charge. 4 shows a TCP / IP network accommodating the FOIP function. Protocols used for controlling the access gateway in the soft switch include MGCP, SIP, H.323, and H.248 (Megaco). In this case, the megaco protocol is applied.

However, as the conventional PSTN network market moves to the packet base due to the demand of the consumer's Internet, the market situation is that devices between the conventional network, that is, the PSTN network and the evolved network, that is, the intelligent network coexist. Doing. At this time, the access gateway acts as a bridge between the two networks, and at the same time, the acceptance of additional services supported by the PSTN exchange is being continued. The concept of an access gateway that has a dual FAX device as a terminal is established as FOIP, and the technology for this is defined in the ITU-T T.38 protocol. The problem is that nothing is presented.

In order to solve the above problems, an object of the present invention is to implement a call control for preparing a FAX call, FAX call attempt, FAX call setup and FAX call release for a FAX terminal under the control of an access gateway, and soft switch The purpose of this paper is to provide a process for negotiation of the resource setting and access gateways between the access gateways when reporting for the control request of the channel and the megaco message transmission for the FAX call control of the soft switch.

1 is a diagram illustrating a conventional PSTN based FAX call control system.

2 is a flowchart illustrating a conventional PSTN based FAX call control procedure.

3 is a diagram illustrating a conventional TCP / IP based FAX call control system.

4 is a configuration diagram of a FOIP service of a conventional access gateway.

5 is a view showing a FAX call control system applied to the present invention.

6 shows an access gateway in FIG. 5;

7 is a flowchart illustrating a FAX call control method according to an embodiment of the present invention.

8 is a flowchart illustrating a FAX call preparation process.

9 is a flowchart illustrating a FAX call preparation process.

10 is a flowchart illustrating a FAX call attempt process.

11 is a flowchart illustrating a FAX call attempt process.

12 is a flowchart illustrating a FAX call setup process.

13 is a flowchart showing a FAX call setup process.

14 is a flowchart illustrating a FAX call release procedure.

15 is a flowchart illustrating a FAX call release process.

Explanation of symbols on the main parts of the drawings

10a; Outgoing FAX Terminal 10b: Incoming FAX Terminal

40a: Outgoing Access Gateway 40b: Incoming Access Gateway

50: soft switch

In order to solve the above object, the method for controlling a fax call of the present invention comprises the steps of: preparing a FAX call by inquiring an access gateway to grasp the type and characteristic of a resource; Detecting a CNG and CED signal for setting up the call and attempting a FAX call by setting up a FAX stream path between the corresponding FAX terminals according to the detection of the signal; Establishing a fax call for transmitting a call setup signal and allocating resources by relaying a communication standard for setting of a transmission rate and a specification corresponding to the specification between the terminals of the fax; And receiving a DCN message to release the allocated resource.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The access gateway capable of providing the FOIP service proposed by the FAX call control method according to an embodiment of the present invention not only accommodates a FAX terminal (T.30 protocol based) that uses a FAX service by accessing an existing PSTN exchange, In addition to reducing the operating cost by enabling the transmission of FAX data using the Internet network, the bandwidth of 14.4Kbps is sufficient, so the bandwidth of data transmission is 4 times more efficient than the existing 64Kbps. With access gateway replacing existing PSTN equipment, FOIP function needs to be combined to accommodate the FAX service provided by existing PSTN. Therefore, for this purpose, a process of a control protocol for FAX call control of an access gateway that accepts the T.38 protocol is defined, and an example of control according to a protocol message will be described.

First, a FAX call control system for FOIP applied to a FAX call control method according to an embodiment of the present invention will be described with reference to FIG. 5.

The FAX call control system applied to the present invention includes an originating FAX terminal 10a, an originating access gateway 40a, a soft switch 50, a terminating access gateway 40b, and a terminating FAX terminal 10b. The originating access gateway 40a converts Pulse Code Modulation (PCM) data of the originating FAX terminal 10a into packet data, and the terminating access gateway 40b receives the converted packet data so that the packet data is faxed. Data is detected and converted to PCM data and transmitted to the incoming fax terminal 10b, and the soft switch 50 controls the outgoing access gateway 40a and the incoming access gateway 40b to proceed with the connection of the fax call. .

Next, the configuration of the access gateway 40 will be described with reference to FIG.

FIG. 6 is a diagram illustrating an access gateway in FIG. 5.

The access gateway 40 includes a FAX call control unit (FCCU), a resource control module (42), a megaco protocol module (MPM) 43, and an internet protocol. Internet Protocol Module (IPM) 44 and FAX Protocol Unit (FPU) 45, wherein the FAX call control unit 41 controls the FAX call, and the resource The control unit 42 performs time switch and port resource control in the system, and the megaco protocol unit 43 encodes / decodes the megaco protocol, and the Internet The protocol unit 44 generates / decomposes the TCP / IP packet data, and the FAX protocol unit 45 is related to the entire FAX call and compensates for the loss of the packet generated on the packet network and checks the timing. Request a retransmission.

The access gateway 40 proceeds to control the FAX call from the time point at which the FAX call detection report is reported by the FAX protocol unit 45, which is different from the control of the existing voice call. In addition, as the control is also performed by the soft switch 50 by the megaco protocol, the access gateway 40 controls the FAX protocol unit 45 according to the contents contained in the megaco message mutually defined with the corresponding soft switch 50. To control.

Hereinafter, a FAX call control method according to an embodiment of the present invention will be described with reference to FIG. 7.

7 is a flowchart illustrating a FAX call control method according to an embodiment of the present invention.

First, when the soft switch 50 and the access gateway 40 and the basic service change procedure are completed, the soft switch 50 basically identifies the types and characteristics of resources supported by the access gateway 40 for call control of the access gateway 40. In order to proceed to the inquiry through the megaco message to the access gateway 40 to prepare a fax call (Call Setup) (S701).

In addition, the access gateway 40 detects the CNG and CED signals generated by the FAX terminal 10 in order to set up a call, and attempts a FAX call by setting a FAX stream path between the FAX terminals 10 according to the detection of the signal. (S702).

In addition, the FAX terminal 10 transmits a call setting signal to a counterpart FAX terminal by relaying the soft switch 50 to a communication standard set therein for setting the details regarding the transmission speed and the specification between the terminals 10 of the FAX. A FAX call is transmitted and an access gateway 40 allocates a resource (S703).

Accordingly, the access gateway 40 receives the DCN message, which is the transmission termination signal, releases the allocated resource, and releases the FAX call (S704).

Hereinafter, the FAX call preparation process S701 will be described with reference to FIGS. 8 and 9.

8 is a flowchart illustrating a FAX call preparation process, and FIG. 9 is a flowchart illustrating a FAX call preparation process.

As illustrated in FIG. 8, the soft switch 50 transmits and receives an AG Capability Request message and an AG Capability Response message with the access gateway 40 to perform a basic setting procedure. After the (Service Change) is completed, inquiries through the megaco message to the access gateway 40 to grasp the type and characteristics of resources supported by the access gateway 40 for call control of the access gateway 40. do. Through this, the soft switch 50 stores controllable details such as the type and call type of the subscriber of the access gateway 40 therein. Therefore, the FOIP control process required for the access gateway 40 response procedure is presented.

FIG. 9 illustrates a response process of the access gateway 40 to a command of the soft switch 50. The content of the access switch 40 to inform the request of the soft switch 50 for the FOIP service is shown first. The Internet protocol unit 44 of the access gateway 40 receives the megaco message IP packet data regarding the type and characteristic query of the resource from the soft switch 50 (S901), and the IP header of the corresponding message. Remove and transfer only UDP (User Datagram Protocol) packet to the megaco protocol unit 43 (S902).

Accordingly, the megaco protocol unit 43 decodes the UDP packet message and transmits the query command to the FAX call control unit 41 (S903).

Accordingly, the FAX call control unit 41 inquires of the FAX protocol unit 45 whether FAX support is performed (S904).

Accordingly, the FAX protocol unit 45 determines whether FAX support is possible (S905), and when the FAX support is possible, notifies the FAX call control unit 41 that the corresponding FAX support is possible, and the FAX call control unit 41 supports FAX support. The response megaco message with the possible notation is transmitted to the megaco protocol unit 43 (S906).

On the other hand, when FAX support is not possible, the FAX call control unit 41 notifies that the FAX support is not possible, and the FAX call control unit 41 sends a response megaco message indicating that the FAX support is not possible. Transfer to (S907).

Accordingly, after the steps S906 and S907, the megaco protocol unit 43 encodes the response megaco message and transmits the response megaco message to the internet protocol unit 44 (S908).

Accordingly, the internet protocol unit 44 converts the encoded response megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S909).

FIG. 9 is a detailed description of a query and a response between the soft switch 50 and the access gateway 40. The soft switch 50 provides a query for FAX codec information and RTP resources that the access gateway 40 can support. do. This command protocol is an Audit command and is used for querying the resource and configuration information of the access gateway 40.

Hereinafter, the FAX call attempt process S702 will be described with reference to FIGS. 10 and 11.

10 is a flowchart illustrating a FAX call attempt procedure, and FIG. 11 is a flowchart illustrating a FAX call attempt procedure.

Since the FAX call is intended to transmit a FAX stream, signals such as CED, CNG, DCN, etc. for call start and call end between the FAX terminals 10 must be exchanged. Dual CED, CNG is associated with the call attempt process (S702). As shown in FIG. 10, when the access gateway 40 receives the corresponding signal and reports the signal to the soft switch 50, the control information is managed by the soft switch 50.

Referring to FIG. 10, the originating access gateway 40a first detects the CNG from the originating FAX terminal 10a, and then generates and transmits the corresponding CNG to the soft switch 50.

Accordingly, the soft switch 50 transmits the generated CNG to the destination access gateway 40b, and the destination access gateway 40b transmits the transmitted CNG to the destination FAX terminal 10b.

Then, the incoming access gateway 40b detects the CED from the incoming FAX terminal 10b, generates the corresponding CED, and transmits the CED to the soft switch 50.

Accordingly, the soft switch 50 transmits the generated CED to the originating access gateway 40a, and the corresponding originating access gateway 40a transmits the transmitted CED to the originating FAX terminal 10a.

FIG. 11 illustrates a process for establishing a FAX stream path between FAX terminals 50 connected to two access gateways 40. The two access gateways 40 are generated by the FAX terminal 10 for call setup. The FAX call is initiated by detecting a signal and by a FAX control procedure according to the signal detection. In the FAX call attempt process (S702), the actual FAX stream is not transmitted, and a signal is exchanged for setting a path. The access gateway 40 can generate CNG and CED and can detect the FAX stream. In the case of the destination access gateway 40a, since the detection contents of the originating access gateway 40b are transmitted by the soft switch 50, the details of enabling the generation of the related CNG and CED after receiving the message have been described. .

First, the access gateway 40 determines whether the CNG or the CED is detected from the FAX terminal 10 or received from the soft switch 50 (S101). In this case, when the subscriber presses the counterpart's FAX terminal number in the FAX terminal 10, the subscriber receives the corresponding FAX tone and detects the CNG or the CED.

As a result of the determination (S101), when the CNG or the CED is detected from the FAX terminal 10, the FAX protocol unit 45 of the access gateway 40 determines whether the CNG or CED is a corresponding CNG signal or CED. The signal is transmitted to the FAX call control unit 41 (S102).

Accordingly, the FAX call controller 41 determines whether the transmitted signal is a CNG signal (S103).

As a result of the determination (S103), when the transmitted signal is a CNG signal, the FAX call control unit 41 determines whether it is necessary to set a FAX call type to the corresponding CNG signal (S104). That is, since the CNG is detected at the calling party and the CED is detected at the receiving party, the call / type is set by setting a FAX call type.

At this time, when it is not necessary to set a FAX call type in the CNG signal (S104), the FAX call control unit 41 requests the FAX protocol unit 45 to retransmit the FAX message (S108).

On the other hand, when it is necessary to set a FAX call type to the CNG signal as a result of the determination (S104), the FAX call control unit 41 sets the FAX call type as the outgoing FAX call type and the CNG mega with the corresponding type set. The nose message is transmitted to the megaco protocol unit 43 (S105).

Accordingly, the megaco protocol unit 43 encodes the CNG megaco message and transmits it to the internet protocol unit 44 (S106).

Accordingly, the internet protocol unit 44 converts the encoded CNG megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S107).

On the other hand, in the determination result (S103), when the transmitted signal is not a CNG signal, the FAX call control unit 41 determines whether the transmitted signal is a CED signal (S109).

At this time, when the determination result (S109), the transmitted signal is not a CED signal, the FAX call control unit 41 requests the FAX protocol retransmission to the FAX protocol unit 45 (S108).

As a result of the determination (S109), when the transmitted signal is a CED signal, the FAX call controller 41 determines whether a FAX call type is set in the corresponding CED signal (S110).

At this time, when the determination result (S110) and the FAX call type is not set, the FAX call control unit 41 requests the FAX protocol unit 45 to retransmit the FAX message (S108).

On the other hand, when the determination result (S110), the FAX call type is set, the FAX call control unit 41 transmits the CED megaco message is set to the megaco protocol unit 43, the corresponding The megaco protocol unit 43 encodes the CED megaco message and transmits the encoded message to the internet protocol unit 44 (S111).

Accordingly, the internet protocol unit 44 converts the encoded CED megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S112).

On the other hand, when the determination result (S101), the CNG or CED is received from the soft switch 50, the Internet protocol unit 44 of the access gateway 40 is the CNG or received from the soft switch 50 or The IP header of the corresponding message is removed from the CED megaco message IP packet data, and only the CNG or CED UDP packet is transmitted to the megaco protocol unit 43 (S113).

Accordingly, the megaco protocol unit 43 decodes the CNG or CED UDP packet message and transfers the corresponding CNG signal or CED signal to the FAX call controller 41 (S114).

Accordingly, the FAX call controller 41 determines whether the transmitted signal is a CNG signal (S115).

As a result of the determination (S115), when the transmitted signal is a CNG signal, the FAX call control unit 41 sets the corresponding CNG signal as an outgoing FAX call type (S116). That is, since the CNG is detected at the calling party and the CED is detected at the receiving party, the FNG call type is set to distinguish between originating and incoming calls.

Then, the FAX call control unit 41 transmits the CNG megaco message in which the outgoing FAX call type is set to the megaco protocol unit 43, and the megaco protocol unit 43 plays the FAX CNG (S117). .

Thereafter, the megaco protocol unit 43 encodes the CNG megaco message and transmits the encoded CNG megaco message to the internet protocol unit 44 (S118).

Accordingly, the internet protocol unit 44 converts the encoded CNG megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S119).

On the other hand, in the determination result (S115), when the transmitted signal is not a CNG signal, the FAX call control unit 41 determines whether the transmitted signal is a CED signal (S120).

At this time, when the determination result (S120), if the transmitted signal is not a CED signal, the FAX call control unit 41 generates a CED megaco message indicating the FAX message retransmission to generate the corresponding retransmission CED megaco message It transmits to the megaco protocol unit 43 (S121).

Accordingly, the megaco protocol unit 43 encodes the transmitted retransmission CED megaco message and transmits it to the internet protocol unit 44 (S122).

Accordingly, the internet protocol unit 44 converts the encoded retransmission CED megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S123).

On the other hand, when the determination result (S120), the transmitted signal is a CED signal, the FAX call control unit 41 determines whether the FAX call type is set in the corresponding CED signal (S124).

In this case, when the FAX call type is not set in the CED signal (S124), the FAX call control unit 41 generates a CED megaco message indicating a FAX message retransmission and generates the corresponding retransmission CED. The megaco message is transmitted to the megaco protocol unit 43 (S121).

On the other hand, when the FAX call type is set to the CED signal as a result of the determination (S124), the FAX call control unit 41 sends the CED megaco message with the FAX call type set to the megaco protocol unit 43. The megacoprotocol 43 transmits the FAX CED (S125).

Hereinafter, the FAX call setup process S703 will be described with reference to FIGS. 12 and 13.

12 is a flowchart illustrating a FAX call setup process, and FIG. 13 is a flowchart illustrating a FAX call setup process.

Looking at the history of the operation in the existing PSTN, the incoming fax terminal (10b) receiving the CED must deliver the communication standard set internally to the other originating fax terminal (10a) to set the details of the transmission speed and specifications between the fax terminals. do. This procedure is illustrated in FIG. 12. In the incoming FAX terminal 10b, after the CED is generated, the V.21 signal containing the transmission standard is transmitted to the destination access gateway 40b, and the FAX of the destination access gateway 40b is transmitted. Detected by the protocol unit 45, it is delivered to the FAX call control unit 41.

At this time, the FAX call control unit 41 reports the detection history to the soft switch 50, the soft switch 50 transmits the reported details to the originating FAX terminal 10a, FAX connection of the existing voice switch Instruct both access gateways 40 to switch to the connected switch mode. In addition, the destination access gateway 40b for transmitting the FAX packet is instructed to set a port resource, and the command to connect the set port resource to the originating access gateway 40a is issued. If this is done normally between the two ends, the connection of the FAX stream is completed and the actual FAX packet transmission starts.

Referring to Figure 13 will be described in the FAX call setup process.

First, the access gateway 40 determines whether the V.21 message, which is the reception standard and the transmission rate data, is received from the destination terminal 10a or whether the time switch or the port allocation megaco message is received from the soft switch 50 (S301). ).

As a result of the determination (S301), when the V.21 message is received, the FAX protocol unit 45 of the access gateway 40 determines the transmission history of the corresponding V.21 message and sends the determined contents to the FAX call. The control unit 41 transmits to the control unit 41 (S302).

Accordingly, the FAX call control unit 41 determines whether the FAX call type is set (S303).

At this time, when the determination result (S303), the FAX call type is set, the FAX call control unit 41 transmits a V.21 megaco message to the megaco protocol unit 43, the corresponding megaco protocol The unit 43 encodes the V.21 megaco message and transmits the encoded V.21 megaco message to the Internet protocol unit 44 (S304).

Accordingly, the internet protocol unit 44 converts the encoded V.21 megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S305).

On the other hand, when the determination result (S303) and the FAX call type are not set, the FAX call control unit 41 requests the FAX protocol unit 45 to retransmit the FAX message (S306).

On the other hand, when receiving the determination result (S301), the time switch or the port allocation megaco message, the Internet protocol unit 44 of the access gateway 40 is the time switch received from the soft switch 50 Alternatively, the IP header of the corresponding message is removed from the port allocation megaco message IP packet data, and only the time switch or the photo allocation packet is transmitted to the megaco protocol unit 43 (S307).

Accordingly, the megaco protocol unit 43 decodes the time switch or port assignment packet message and transmits the decoded message to the FAX call control unit 41 (S308).

Accordingly, the FAX call controller 41 determines whether the decoded message is a time switch assignment message (S309).

At this time, when the determination result (S309), the time switch assignment message, the FAX call control unit 41 makes the FAX switch resource query to the resource control unit 42 (S310).

Accordingly, the resource controller 42 determines whether the time switch allocation resource is available (S311).

At this time, when the determination result (S311), when the time switch allocation resources are available, the resource control unit 42 transmits the time switch resource available megaco message to the megaco protocol unit 43, the corresponding megaco protocol The unit 43 encodes the corresponding time switch resource available megaco message and transmits it to the internet protocol unit 44 (S312).

Accordingly, the internet protocol unit 44 converts the encoded time switch resource available megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S313).

On the other hand, when the determination result (S311), when the time switch allocation resource is unavailable, the resource control unit 42 notifies the FAX call control unit 41 that the time switch resource is not available, the corresponding FAX call control unit 41 ) Transmits the time switch resource unavailable megaco message displaying the error message details to the megaco protocol unit 43 (S314).

Accordingly, the megaco protocol unit 43 encodes the time switch resource unavailable megaco message and transmits it to the internet protocol unit 44 (312).

Accordingly, the internet protocol unit 44 converts the encoded time switch resource unavailable megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S313).

On the other hand, if it is not the time switch assignment message (S309), the FAX call control unit 41 determines whether the port assignment message (S315).

At this time, in the case of the determination result (S315) and the port assignment message, the FAX call control unit 41 makes a FAX port resource inquiry to the resource control unit 42 (S316).

Accordingly, the resource controller 42 determines whether the port allocation resource is available (S317).

At this time, when the determination result (S317), when the port allocation resource is available, the resource control unit 42 notifies the FAX call control unit 41 that the corresponding port resource is available, the corresponding FAX call control unit 41 is assigned The port resource available megaco message indicating the details is transmitted to the megaco protocol unit 43 (S318).

Accordingly, the megaco protocol unit 43 encodes the port resource available megaco message and transmits it to the internet protocol unit 44 (S312).

Accordingly, the Internet protocol unit 44 converts the encoded port resource available megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S313).

On the other hand, in the determination result (S317), when the port allocation resource is unavailable, the resource control unit 42 notifies the FAX call control unit 41 that the corresponding port allocation resource is not available, and the corresponding FAX call control unit 41 Transmits the port resource unavailable megaco message displaying the error message details to the megaco protocol unit 43 (S314).

Accordingly, the megaco protocol unit 43 encodes the port resource unavailable megaco message and transmits it to the internet protocol unit 44 (312).

Accordingly, the internet protocol unit 44 converts the encoded port resource unavailable megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S313).

On the other hand, if the determination result (S315), and not the port assignment message, the FAX call control unit 41 determines whether to play V.21 (S319).

At this time, when the determination result (S319), the V.21 should be played, the FAX call control unit 41 plays the corresponding V.21 (S320).

The FAX call control unit 41 transmits the V.21 response megaco message to the megaco protocol unit 43, and the megaco protocol unit 43 encodes the corresponding V.21 response megaco message to the The transmission is sent to the Internet protocol unit 44 (S312).

Accordingly, the internet protocol unit 44 converts the encoded V.21 response megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S313).

On the other hand, when the determination result (S319) does not play the V.21, the FAX call control unit 41 generates a V.21 message indicating the retransmission of the FAX message, the corresponding retransmission V.21 mega The nose message is transmitted to the megaco protocol unit 43 (S322).

Accordingly, the megaco protocol unit 43 encodes the retransmission V.21 megaco message and transmits it to the internet protocol unit 44 (S312).

Accordingly, the internet protocol unit 44 converts the encoded retransmission V.21 megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S313).

Hereinafter, the FAX call release process S704 will be described with reference to FIGS. 14 and 15.

14 is a flowchart illustrating a FAX call release process, and FIG. 15 is a flowchart illustrating a FAX call release process.

For FAX calls, it features a one-way fax stream. According to this characteristic, the transmission completion message of the originating fax terminal 10a should be delivered to the called fax terminal 10b. The transmission end signal should be transmitted from the originating FAX terminal 10a to the destination FAX terminal 10b as a DCN signal. This process is shown in FIG. 14 and the control procedure of the access gateway 40 in this process is shown in FIG. The access gateway 40 receives the DCN signal and proceeds to report the call release command of the soft switch 50. Since the call setup and release are controlled by the soft switch 50, the access gateway 40 waits for the command and proceeds with the operation of the command upon receipt of the command. For this purpose, the access gateway 40 operates with the control procedure of FIG.

First, the access gateway 40 determines whether it has received a DCN message from the soft switch 50 indicating completion of FAX data transmission or a resource release megaco message (S501).

As a result of the determination (S501), when the DCN message is received, the FAX protocol unit 45 of the access gateway 40 determines the transmission history of the corresponding DCN message and sends the determined contents to the FAX call control unit 41. Transfer to (S502).

Accordingly, the FAX call control unit 41 determines whether a FAX call type is set (S503).

At this time, when the determination result (S503), the FAX call type is set, the FAX call control unit 41 generates a command completion response DCN megaco message to the corresponding command completion response DCN megaco protocol unit 43 Transfer to (S504).

Accordingly, the megaco protocol unit 43 encodes the command completion response DCN megaco message and transmits the encoded message to the internet protocol unit 44 (S505).

Accordingly, the internet protocol unit 44 converts the encoded command completion response DCN megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S506).

On the other hand, when the determination result (S503) and the FAX call type are not set, the FAX call control unit 41 requests the FAX protocol unit 45 to retransmit the FAX message (S507).

On the other hand, when the determination result (S501), the resource release megaco message is received, the Internet protocol unit 44 of the access gateway 40, the resource release megaco message received from the soft switch 50 Removes the IP header of the message from the IP packet data and delivers only the resource release packet to the megaco protocol unit 43 (S508).

Accordingly, the megaco protocol unit 43 decodes the resource release packet message and transmits it to the FAX call control unit 41 (S509).

Accordingly, the FAX call controller 41 determines whether the decoded message is a resource release message (S510).

As a result of the determination (S510), in the case of the resource release message, the FAX call controller 41 determines whether a FAX call type is set (S511).

At this time, when the determination result (S511), the FAX call type is set, the FAX call control unit 41 to the FAX switch resource release query to the resource control unit 42, this resource control unit 42 Determines whether the FAX switch resource is released (S512).

As a result of the determination (S512), when the FAX switch resource is released, the resource controller 42 determines whether the FAX port resource is released (S513).

As a result of the determination (S513), when the FAX port resource is released, the resource control unit 42 notifies the FAX call control unit 41 that the corresponding resource is released, and the FAX call control unit 41 sends a command completion response resource. A release megaco message is generated and transmitted to the megaco protocol unit 43 (S514).

Accordingly, the megaco protocol unit 43 encodes the command completion response resource release megaco message and transmits it to the internet protocol unit 44 (S515).

Accordingly, the internet protocol unit 44 converts the encoded command completion response resource release megaco message into IP packet data and transmits the converted IP packet data to the soft switch 50 (S516).

On the other hand, when the determination result (S513), the FAX port resource is not released, the resource control unit 42 notifies the FAX call control unit 41 that the corresponding FAX port resource is released, the corresponding FAX call control unit ( 41) transmits the FAX port resource release megaco message indicating the error message details to the megaco protocol unit 43 (S521).

On the other hand, when the determination result (S512), the FAX switch resource is not released, the resource control unit 42 notifies the FAX call control unit 41 that the corresponding FAX switch resource is released, the corresponding FAX call control unit 41 ) Transmits the FAX switch resource release megaco message indicating the error message details to the megaco protocol unit 43 (S521).

In addition, if the determination result (S511), the FAX call type is not set, the FAX call control unit 41 generates a resource release message indicating the retransmission of the FAX message to mega-message generated retransmission resource release megaco message The protocol is transmitted to the nose 43 (S520). Then, the process goes through steps S515 and S516.

In addition, when it is determined that the determination result (S510) is not the resource release message, the FAX call control unit 41 determines whether it is a DCN message (S517).

At this time, when the determination result (S517), the DCN message, the FAX call control unit 41 plays the DCN (S518).

The FAX call control unit 41 transmits the DCN response megaco message to the megaco protocol unit 43, and the megaco protocol unit 43 encodes the DCN response megaco message to the Internet protocol unit ( 44) (S519). Thereafter, the steps S515 and S516 are further performed.

On the other hand, if the determination result (S517), the DCN mesh is not, the FAX call control unit 41 generates a DCN message indicating the retransmission of the FAX message megacoprotocol unit for the generated retransmission DCN megaco message Transmit to 43 (S520). Then, the process goes through steps S515 and S516.

In addition, the embodiment according to the present invention is not limited to the above-mentioned, and can be implemented by various alternatives, modifications, and changes within the scope apparent to those skilled in the art.

As described above, the present invention enables the FOIP service to be provided in the access gateway, thereby creating a new service and accommodating the existing device without the hassle of replacing the existing FAX device. The present invention also provides a procedure for T.38 FAX call processing. By using this procedure, FAX call processing is possible by interworking with FPU that provides FOIP function, which saves the existing transmission bandwidth by using FAX service through access network through access gateway. The network configuration can be removed. In addition, FAX service can be performed using the T.38 protocol, which is a common protocol, thereby ensuring mutual compatibility.

Claims (3)

Preparing a FAX call by inquiring an access gateway to grasp the type and characteristic of the resource; Detecting a CNG and CED signal for setting up the call and attempting a FAX call by setting up a FAX stream path between the corresponding FAX terminals according to the detection of the signal; Establishing a fax call for transmitting a call setup signal and allocating resources by relaying a communication standard for setting of a transmission rate and a specification corresponding to the specification between the terminals of the fax; And receiving a DCN message to release the allocated resource. The method of claim 1, The FAX call preparation process, Receiving megaco message IP packet data regarding the resource type and characteristic query, removing the IP header of the corresponding message, and forwarding only UDP packets; Decoding the UDP packet message to transmit a corresponding inquiry command and inquiring FAX support; Transmitting a response megaco message indicating that the corresponding FAX is available and supporting the FAX support if the FAX is supported; And encoding and transmitting the response megaco message and converting the encoded response megaco message into IP packet data. The method of claim 2, The FAX call preparation process, And transmitting a response megaco message indicating that the FAX is not supported and displaying the FAX not supported when the FAX is not supported.