JP2000341342A - Device and method for communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a defect in communications due to a difference in transmission quality between two networks by securing the communication quality in a 2nd network and determining a reception system for data from a 1st network according to the secured quality. SOLUTION: Receiving a call from a facsimile terminal connected to PSTN 111, the device starts operating to instruct an NCU 107 to form a DC loop and then inquires of a gatekeeper as to usable bandwidth through a LAN 112 to secure a transmission band. When the secured band is narrower than a previously set value, CED is sent out answering to a CNG or CI signal sent out by the opposite facsimile. When the secured band is broader than the set value, on the other hand, ANSam is sent out. Then negotiation is carried out by a system prescribed in ITU-T recommendation V.8 to determine the modulation system of a modem 106. Then a communication rate is determined by following a specific procedure and the system is made prepared for receiving image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a communication device for relaying data between different networks, and more particularly to a communication device and a communication method for relaying data from a public line to an IP network.

[0002]

2. Description of the Related Art In recent years, the wide area represented by the Internet
IP networks are generally infiltrated and VoIP (Voice Ov
Attempts have been made to perform communications such as voice calls using an IP network called er IP). Long-distance communication via PSTN can be relayed over the IP network on the way, and benefits such as reduction of communication charges can be enjoyed. . In this case, a gateway device is used as a relay node between the PSTN and the IP network. The IP network is a so-called Best Effort network in which communication quality is not guaranteed because transmission delay and fluctuation occur due to the influence of traffic. Therefore, RSVP (Resource Reservati
On the other hand, there has been proposed a method for guaranteeing the quality of communication on an IP network by securing necessary communication quality (bandwidth, delay, fluctuation, etc.) using a resource reservation protocol such as an on protocol. H.323 is defined as an ITU-T standard for performing audio-visual communication using such a quality non-guaranteed network.

[0003]

When there is a difference in transmission quality (transmission speed) between the PSTN line and the IP network, the gateway device serving as a relay node has the following problems. That is, when the transmission speed from the PSTN is significantly higher than the transmission speed to the IP network, the receiving buffer becomes full immediately and data overrun occurs. Therefore, the communication time is prolonged due to data retransmission and the like, and the communication fee on the PSTN line is rather increased. Furthermore, even if the data is retransmitted, the data cannot be recovered and a communication error eventually occurs. The present invention has been made to solve the above-described problem, and has as its object to provide a communication device (gateway device) that prevents occurrence of communication failure due to a difference in transmission quality between two networks.

[0004]

According to a first aspect of the present invention, there is provided a communication apparatus for relaying data from a first network to a second network. And a control means for determining a method of receiving data from the first network based on the secured quality.

Further, according to a second invention of the present application, in the first invention of the present application, the reception method is a transmission rate.

Further, according to a third aspect of the present invention, there is provided a communication device for relaying data from a public line to a computer network, comprising: a band securing means for securing a transmission band in the computer network; And control means for determining a method of receiving data from the public line based on

According to a fourth invention of the present application, in the third invention of the present application, the reception system is a transmission speed.

Further, according to a fifth aspect of the present invention, there is provided a communication apparatus for relaying facsimile data from a public line to an IP network, comprising: a bandwidth securing means for securing a transmission bandwidth in the IP network; Control means for determining a method of receiving facsimile data from the public line based on a band.

According to a sixth invention of the present application, in the fifth invention of the present application, the control means, when responding to an incoming call from a public line, if the secured transmission band is equal to or more than a predetermined value, It is characterized by responding with the procedure signal of ITU-T Recommendation V.8, otherwise responding with the procedure signal of ITU-T Recommendation T.30.

According to a seventh invention of the present application, in the fifth invention of the present application, there is provided a conversion table in which a transmission band and a facsimile transmission speed are associated with each other. The transmission speed obtained from the table is declared.

According to an eighth invention of the present application, in any one of the fifth to seventh inventions of the present application, the band securing means secures a transmission band by an RSVP protocol.

According to a ninth invention of the present application, in any one of the fifth to seventh inventions of the present application, the band securing means is defined in ITU-T Recommendation H.264. The transmission band is secured by making a request to a H.323-compliant gatekeeper.

[0013] A tenth invention of the present application is a communication method for relaying data from a first network to a second network, wherein a quality securing step for securing communication quality in the second network. And a control step of determining a method of receiving data from the first network based on the secured quality.

According to an eleventh aspect of the present invention, in the tenth aspect of the present invention, the reception system is a transmission speed.

According to a twelfth aspect of the present invention, there is provided a communication method for relaying data from a public line to a computer network, comprising: a bandwidth securing step for securing a transmission bandwidth in the computer network; And a control step of determining a method of receiving data from the public line based on the control method.

According to a thirteenth invention of the present application, in the twelfth invention of the present application, the reception system is a transmission speed.

A fourteenth invention of the present application is a communication method for relaying facsimile data from a public line to an IP network, comprising: a bandwidth securing step for securing a transmission bandwidth in the IP network; Controlling a method of receiving facsimile data from the public line based on a band.

According to a fifteenth invention of the present application, in the fourteenth invention of the present application, the control step includes the step of: It is characterized by responding with the procedure signal of ITU-T Recommendation V.8, otherwise responding with the procedure signal of ITU-T Recommendation T.30.

The sixteenth invention of the present application is based on the fourteenth invention of the present application, further comprising a conversion table in which a transmission band and a facsimile transmission speed are associated with each other.
The transmission speed obtained from the secured transmission band and the conversion table is declared.

According to a seventeenth aspect of the present invention, in any one of the fourteenth to sixteenth aspects of the present invention, the bandwidth securing step secures a transmission bandwidth by an RSVP protocol.

According to an eighteenth aspect of the present invention, in any one of the fourteenth to sixteenth aspects of the present invention, the band securing step is performed according to ITU-T Recommendation H.264. The transmission band is secured by making a request to a H.323-compliant gatekeeper.

According to a nineteenth aspect of the present invention, there is provided a computer-readable storage medium storing a communication method program for relaying data from a first network to a second network. A program for executing a quality assurance step of ensuring communication quality in a network and a control step of determining a method of receiving data from the first network based on the secured quality are stored. .

According to a twentieth aspect of the present invention, there is provided a computer-readable storage medium storing a communication method program for relaying facsimile data from a public line to an IP network. And a control step of determining a method of receiving facsimile data from the public line based on the secured transmission band.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<First Embodiment> As a first embodiment, a V.V. A case will be described where it is determined whether to receive in the 34 mode. FIG. 2 is an explanatory diagram showing an example of a system configuration of a network using the facsimile gateway device according to the first embodiment of the present invention. 201, 202, 212, and 213 are facsimile machines connected to the PSTN,
01 conforms to ITU-T Recommendation V.34 and enables high-speed communication. 203
And 211 are the facsimile gateway device according to the present invention, 204 is a gatekeeper for managing the H.323 system, 20
5, 206, 209, and 210 are terminals conforming to H.323, and are under the control of the gatekeeper 204 together with the facsimile gateway devices 203 and 211. 207 and 208
Is a router. For example, when transmitting an image from the facsimile apparatus 201 to the facsimile apparatus 212, after receiving an incoming call from the facsimile apparatus 201, the facsimile gateway apparatus inquires the gatekeeper 204 about the available bandwidth and communicates according to the acquired bandwidth. Facsimile communication is relayed and received by the method. The relayed image reaches the facsimile gateway device 211 via an IP network such as the routers 207 and 208. here,
The address in the IP network of the facsimile gateway device 211 is obtained from the gatekeeper 204. The facsimile gateway 211 transmits the received image to the PSTN
It relays to the facsimile machine 212 via

FIG. 1 is a block diagram showing the configuration of the facsimile apparatus according to the first embodiment. In FIG. 1, reference numeral 101 denotes a CPU, which controls blocks of the entire apparatus via a system bus 108. A ROM 102 stores a control program of the CPU such as a facsimile protocol, a TCP / IP protocol, and a mounting code of a network application. 10
Reference numeral 3 denotes a RAM, which is composed of an SRAM, a DRAM, or the like, and stores program control variables, image data, and the like. In addition, setting values registered by the operator, management data of the apparatus, and various work buffers are also stored in this.

Reference numeral 104 denotes a frame assembling / disassembling unit,
Datagram decomposition generation, TCP segment data decomposition generation, UDP data generation decomposition, facsimile EC
It performs assembly and disassembly of transmission data frames according to each communication protocol such as generation and disassembly of M frames. 1
Reference numeral 05 denotes a facsimile protocol control unit.
6 to control communication protocols related to facsimile such as ITU-T Recommendation T.30, V.34 and V.8. A modem 106 modulates and demodulates a signal transmitted / received via the PSTN 111. 107 is a line control unit (N
CU), and performs call connection control of the PSTN 111. 109
Is a LAN control unit that controls the LAN interface 110 to transmit and receive Ethernet frames according to IEEE802.3.
This is performed via the AN 112.

Next, the operation of the facsimile gateway device according to the first embodiment of the present invention will be described with reference to the flowchart of FIG. FIG. 3 is a flowchart showing the operation of the facsimile gateway device according to the first embodiment of the present invention.
2 and reads out and executes the program based on this flowchart. First, when an incoming call is received from the facsimile terminal 201 connected to the PSTN, the operation starts. After instructing the NCU 107 to form a DC loop, the available bandwidth is inquired to the gatekeeper 204 via the LAN 112 to secure the transmission bandwidth (S100). ).

In the judgment of S102, if the transmission band secured in S100 is lower than the preset value, the CNG (1100 Hz single tone signal) or CI signal (modulated by V.21) transmitted by the other party facsimile is transmitted. A CED (2100 Hz single tone signal) is transmitted as a response to the default data sequence of 300 bps (S10
6). Then, set the modem 106 to V.21 (300bps, FSK)
A series of operations in phase B defined in TU-T Recommendation T.30 are performed to prepare for receiving image data (S107, S10)
8). At this time, negotiations regarding the communication speed and the modulation method are performed with the calling terminal 201, but the maximum speed is limited to 14.4 Kbps in the protocol based on the standard T.30.

On the other hand, if it is determined in S102 that the transmission band secured in S100 is equal to or greater than a preset value, ANSam (amplitude modulated 2100 Hz cosine signal) is transmitted (S103). Thereafter, negotiation is performed according to the method specified in ITU-T Recommendation V.8, and the modulation method of the modem 106 is determined (S104). In this case, the maximum speed can be up to 33.6 kbps in V.34. Next, the capability negotiation and training specified in V.34 are performed, and the communication speed is finally determined to prepare for reception of image data (S105).

The image data demodulated by the modem 106 is temporarily buffered in the RAM 103, and then the frame assembling / disassembling unit 104 adds a TCP header and an IP header to create an IP datagram.
(S109). The LAN control unit 109 adds the IP datagram to the IEEE803.2 header information and the like and adds the IP datagram to the LAN1 via the LAN interface 110.
12 (S110). ITU-T for upper layer protocol (application layer protocol) on LAN
Although a protocol such as Recommendation T.38 can be used, an original data transfer protocol may be used. In S111,
It is determined whether the output of the received image data to the LAN 112 has been completed. If the output has not been completed, the process returns to S109. If the output has been completed, the operation ends.

In the above embodiment, the facsimile apparatus
Data from 201 is further PST via IP network
In the above example, the data is transmitted to the facsimile apparatus 212 connected to the N.
It goes without saying that the present invention can be applied to a case where the data is transmitted to 205 or the like.

As described above, when a certain connection quality can be secured in the IP network upon receiving an incoming call from the PSTN, relaying is performed in the high-speed V.34 mode. By using a relatively low-speed mode such as 17, V.29, or V.27ter, it is possible to prevent data overrun or the like.

<Second Embodiment> As a second embodiment, a case will be described in which facsimile communication is relayed based on the obtained utilization bandwidth and the transmission rate obtained from the bandwidth / transmission rate conversion table. The configuration of the facsimile gateway device according to the present embodiment is the same as that of the first embodiment, and a description thereof will be omitted.

The operation of the facsimile gateway device according to the second embodiment will be described with reference to the flowchart of FIG. FIG. 4 is a flowchart showing an operation of the facsimile gateway device in the second embodiment,
The CPU 101 reads and executes a program stored in the ROM 102 based on the present flowchart. First, when an incoming call is received from the facsimile terminal 201 connected to the PSTN 111, the operation starts, instructs the NCU 107 to form a DC loop, inquires the available bandwidth to the gatekeeper 204, and secures the transmission bandwidth (S201). Gatekeeper 204
The available bandwidth information returned from the T. is converted into a bandwidth by using a bandwidth / transmission rate conversion table stored in the ROM 102 in advance.
30 The digital identification signal “DIS” is converted into an image transmission speed parameter (S202). Here, an example of the data structure of the band / transmission rate conversion table is shown in FIG. In the example of FIG. 3, at least the transmission speed of the facsimile
It is designed to require 20% more transmission bandwidth. For example, when receiving facsimile at 2400bps,
The transmission line of 2880 bps, which is an increase of 20%, is the lowest line. Also, the secured transmission band is 2879 bits
In the case of / sec or less, it is determined that the connection is not possible, and although not shown in the flowchart, the line may be disconnected or the call may not be answered.

When a CNG signal is received from the partner facsimile machine 201 (S203), a CED signal is transmitted (S204). Here, the CNG signal is detected in order to determine that the other party is a facsimile machine.
You may move to 04.

Thereafter, the modem 106 is switched to V.21 (300 bps, FSK)
And sends a DIS signal in accordance with ITU-T Recommendation T.30 (S20
Five). At this time, the image transmission speed information parameter obtained from the bandwidth / transmission speed conversion table in step S202 is DIS
Is set and transmitted. Later ITU-T Recommendation T.3
Fax protocol control unit performs facsimile communication operation according to 0
This is performed using the 105, the modem 106, and the NCU 107 (S206). Modem 10
The image data demodulated in 6 is temporarily buffered in the RAM 103, and then a TCP header and an IP header are added in the frame assembling / disassembling unit 104 to create an IP datagram, which is transferred to the LAN control unit 109 (S207).

The LAN control section 109 adds the header data specified in IEEE803.2 to the IP datagram and outputs the IP datagram to the LAN via the LAN interface 110 (S208). As an upper layer protocol (application layer protocol) on the LAN, a protocol such as ITU-T Recommendation T.38 can be used, but an original data transfer protocol may be used. In S209, it is determined whether or not the output of the received image data to the LAN 112 has been completed. If the output has not been completed, the process returns to S207, and if completed, the operation ends.

As described above, there is a conversion table in which the bandwidth secured in the IP network and the facsimile communication capability (for example, transmission speed) are associated with each other. The obtained facsimile communication capability is defined by D specified in ITU-T Recommendation T.30.
By reflecting the bits on appropriate bits of IS (digital identification signal), the transmission speed from the PSTN can be optimized and the occurrence of data overrun or the like can be prevented.

<Third Embodiment> As a third embodiment, a case where a wireless section exists in an IP network will be described. FIG. 7 is a diagram illustrating an example of a system configuration of a network using a facsimile gateway device according to the third embodiment of the present invention. 701,702 is PSTN
Facsimile machine connected to the 703 is a facsimile gateway device of the present invention, 704 is a gatekeeper for managing the H.323 system, 706 and 707 are terminals conforming to H.323, and the facsimile gateway device
Along with 703, it is under the control of the gatekeeper 704. Reference numeral 708 denotes a router, and 705 denotes a PIAFS-compatible router capable of transmitting and receiving IP packets using the PIAFS protocol. 709
Reference numerals 710 and 710 denote LANs to which a plurality of terminals are connected. Here, from the facsimile machine 701 to L
For facsimile communication to a terminal in AN709,
After receiving the incoming call from the facsimile apparatus 701, the facsimile gateway apparatus 703 queries the gatekeeper 704 for an available bandwidth, and relays facsimile communication by a communication method according to the secured bandwidth.

FIG. 6 is a block diagram showing the configuration of a third embodiment of the facsimile apparatus according to the present invention. In the figure, 101 to 108 are the same as those in FIG. 1 of the first embodiment, and the same reference numerals are used as in FIG. 6
A wireless communication control unit 01 performs TDMA processing such as frame disassembly / assembly, scramble processing, and modulates transmission data and demodulates received data. An RF (high frequency) unit 602 transmits and receives radio waves from an antenna. 60
A PIAFS control unit 3 performs transmission control such as error correction and flow control during data communication.

The operation of the facsimile gateway device 703 according to the third embodiment of the present invention will now be described with reference to the flowchart of FIG. FIG. 8 shows a third embodiment of the present invention.
10 is a flowchart illustrating an operation of the facsimile gateway device in the embodiment of FIG.
The program based on this flowchart stored in M102 is read and executed. First, when an incoming call is received from the facsimile terminal 701 connected to the PSTN 111, the operation starts,
Instructs the NCU 107 to form a DC loop, and the gatekeeper 204
It inquires of the available bandwidth and secures the transmission bandwidth (S300).

In the judgment of S302, if the transmission band secured in S300 is lower than the preset value, the CNG signal or CI signal transmitted by the other party facsimile is transmitted as a response to the CNG signal or CI signal.
An ED signal is transmitted (S306). Then, connect the modem 106 to V.21 (3
(00 bps, FSK), and performs a series of operations of phase B defined in ITU-T Recommendation T.30 to prepare for receiving image data (S307, S308). At this time, negotiations regarding the communication speed and the modulation method are performed with the facsimile apparatus 701.
Limited to 14.4Kbps.

If the usable bandwidth returned from the gate keeper 204 is equal to or greater than the preset value in the determination of S302, ANSam (amplitude modulated 2100 Hz cosine signal) is transmitted (S303). After that, negotiation is performed according to the method specified in ITU-T Recommendation V.8, and the modulation method of the modem 106 is determined (S304). In this case, the maximum speed is 3 in V.34
Up to 3.6kbps is possible. Next, capability negotiation and training specified in V.34 are performed, and finally the communication speed is determined to prepare for reception of image data (S305).

The image data demodulated by the modem 106 is temporarily buffered in the RAM 103, and then a TCP header and an IP header are added in the frame assembling / disassembling unit 104 to create an IP datagram, which is passed to the PIAFS control unit 603 (S309) . The PIAFS control unit 603 outputs the IP datagram via the wireless communication control unit 601 and the RF unit 602 after adding header information specified in the PIAFS protocol (S310). As the upper layer protocol of the network (application layer protocol), a protocol such as ITU-T Recommendation T.38 can be used, but a unique data transfer protocol may be used. In S311, it is determined whether the output of the received image data to the PHS wireless line has been completed. If not completed, the process returns to S309, and if completed, the operation ends.

As described above, when a certain connection quality can be ensured in an IP network having a wireless section in the middle, relaying is performed in the high-speed V.34 mode. By using a relatively low-speed mode such as that described above, it is possible to prevent occurrence of data overrun and the like.

In the above embodiment, the case where the facsimile image is relayed has been described. However, the present invention is not limited to this, and it is applicable to a communication protocol such as facsimile communication in which the transmission speed can be selected from a plurality of transmission speeds. The present invention can be applied by determining the transmission speed according to the transmission band.

It goes without saying that the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In that case, the program code for achieving the present invention stored in the storage medium is transferred to the computer (CPU or MPU) of the system or the apparatus.
The object of the present invention is achieved by executing the reading.

When the computer executes the readout program code, it goes without saying that an OS (Operating System) running on the computer may perform a part of the processing.

[0050]

As described above, according to the first, tenth, and nineteenth aspects of the present invention, in relaying data between networks having different communication qualities, the difference in communication qualities can be absorbed and fixed. According to the second and eleventh aspects of the present invention, it is possible to easily obtain a certain level of communication quality by adjusting the transmission rate.

Further, according to the third and twelfth aspects of the present invention, it is possible to obtain a certain level of communication quality without being affected by the traffic of the computer network. According to the thirteenth aspect, it is possible to easily obtain a constant level of communication quality by adjusting the transmission speed.

According to the fifth, fourteenth, and twentieth aspects of the present invention, when facsimile data from a public line is relayed to an IP network, occurrence of communication failure due to overrun of the relay data is prevented. be able to. This makes it possible to realize low-cost, constant-level facsimile communication via the IP network.

Further, according to the sixth and fifteenth aspects of the present invention, a high-speed V.V. By controlling whether to perform reception in the 34 mode, high-speed communication can be performed according to the traffic of the IP network.

Further, according to the seventh and sixteenth aspects of the present invention, it is possible to finely select the transmission speed according to the secured transmission band, and to perform relay at the fastest transmission speed within the secured transmission band. It is possible to do.

Further, according to the eighth and seventeenth aspects of the present invention, by applying the standard RSVP protocol, it is possible to construct a system that is less dependent on a device type.

Further, according to the ninth and eighteenth aspects of the present invention, the standard H.264 standard is used. By securing a transmission band by requesting a gatekeeper conforming to 323, it is possible to construct a system with little dependence on models.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a facsimile gateway device according to a first embodiment.

FIG. 2 is an explanatory diagram showing a network system using the facsimile gateway device according to the first embodiment.

FIG. 3 is a flowchart illustrating an operation of the facsimile gateway device according to the first embodiment.

FIG. 4 is a flowchart illustrating an operation of the facsimile gateway device according to the second embodiment.

FIG. 5 is a diagram illustrating a data structure of a band / transmission rate conversion table according to the second embodiment.

FIG. 6 is a block diagram illustrating a configuration of a facsimile gateway device according to a third embodiment.

FIG. 7 is an explanatory diagram showing a network system using a facsimile gateway device according to a third embodiment.

FIG. 8 is a flowchart illustrating an operation of the facsimile gateway device according to the third embodiment.

[Explanation of symbols]

 Reference Signs List 101 CPU 102 ROM 103 RAM 104 Frame assembling / disassembling unit 105 FAX protocol control unit 106 Modem 107 NCU 108 Bus 109 LAN control unit 110 LAN interface 111 PSTN 112 LAN

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C062 AA02 AA30 AA35 AB44 AC22 AC28 AC38 AC43 AE14 5K030 HB04 HC01 HD03 HD06 LA08 LC09 9A001 CC03 CC07 JJ25 JJ27 KK56

Claims (20)

[Claims] 1. Data from a first network is transferred to a second
A communication device for relaying to the network of
A communication apparatus comprising: a quality assurance unit for ensuring communication quality in the network of (1); and a control unit for determining a method of receiving data from the first network based on the secured quality. 2. The communication device according to claim 1, wherein the receiving method is a transmission speed. 3. A communication device for relaying data from a public line to a computer network, comprising: a band securing unit for securing a transmission band in the computer network; and data from the public line based on the secured transmission band. And a control means for determining a receiving method. 4. The communication device according to claim 3, wherein the receiving method is a transmission speed. 5. Facsimile data from a public line is transmitted to I
A communication device for relaying to a P network,
A bandwidth securing means for securing a transmission bandwidth in the network;
Control means for determining a method of receiving facsimile data from the public line based on the secured transmission band. 6. The control unit, when responding to an incoming call from a public line, when the secured transmission band is equal to or more than a predetermined value,
Responds with the procedure signal of ITU-T Recommendation V.8, otherwise IT
The communication device according to claim 5, wherein the communication device responds with a procedure signal of UT recommendation T.30. 7. A conversion table having a transmission band and a facsimile transmission speed associated with each other, wherein the control unit declares a transmission speed obtained from the secured transmission band and the conversion table. The communication device according to claim 1. 8. The apparatus according to claim 5, wherein said bandwidth securing means secures a transmission bandwidth by an RSVP protocol.
The communication device according to any one of claims 1 to 7. 9. The method according to claim 9, wherein said band securing means is based on ITU-T Recommendation H.264. The communication device according to any one of claims 5 to 7, wherein a transmission band is secured by making a request to a H.323-compliant gatekeeper. 10. A communication method for relaying data from a first network to a second network, the method comprising: securing a communication quality in the second network; A control step of determining a method of receiving data from the first network. 11. The communication method according to claim 10, wherein the receiving method is a transmission speed. 12. A communication method for relaying data from a public line to a computer network, comprising: a band securing step for securing a transmission band in the computer network; and data from the public line based on the secured transmission band. And a control step of determining a receiving method. 13. The communication method according to claim 12, wherein the receiving method is a transmission rate. 14. A communication method for relaying facsimile data from a public line to an IP network,
A communication method, comprising: a bandwidth securing step of securing a transmission bandwidth in a P network; and a control step of determining a method of receiving facsimile data from the public line based on the secured transmission bandwidth. 15. The control step, when responding to an incoming call from a public line, if the secured transmission band is equal to or more than a predetermined value, responds with a procedure signal of ITU-T Recommendation V.8, otherwise, The communication method according to claim 14, wherein the communication method responds with a procedure signal of ITU-T Recommendation T.30. 16. The apparatus according to claim 14, further comprising a conversion table in which a transmission band and a facsimile transmission speed are associated with each other, wherein said control step declares a transmission speed obtained from the secured transmission band and the conversion table. Communication method described in. 17. The communication method according to claim 14, wherein said bandwidth securing step secures a transmission bandwidth by an RSVP protocol. 18. The method according to claim 19, further comprising: The communication method according to any one of claims 14 to 16, wherein a transmission band is secured by making a request to a H.323-compliant gatekeeper. 19. A computer-readable storage medium storing a program for a communication method for relaying data from a first network to a second network, wherein the quality is such that communication quality in the second network is ensured. A computer-readable storage medium storing a program for executing a securing step and a control step of determining a method of receiving data from the first network based on the secured quality. 20. A computer-readable storage medium storing a communication method program for relaying facsimile data from a public line to an IP network, comprising: a bandwidth securing step for securing a transmission bandwidth in the IP network; And a control step of determining a method of receiving facsimile data from the public line based on the obtained transmission band.