JP2004336592A - Group 3 facsimile machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a group 3 facsimile machine which can make a proper communication even when being connected to an IP network through an IP telephone adapter. <P>SOLUTION: In the case that a destination is connected to the IP network, an influence of data errors caused by delay, abandonment, etc. of packets occurring in the IP packet is hardly exerted because a modem speed is set to a prescribed low speed to perform modem training procedures. As a result, the occurrence of data reception errors in the destination is suppressed, so that smooth facsimile communication is possible. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a group 3 facsimile apparatus having an automatic transmission function.
[0002]
[Prior art]
In recent years, with the spread of the Internet as an IP (Internet Protocol) network, a network such as an ADSL (Asymmetric Digital Subscriber Line) and an FTTH (Fiber To The Home) has been developed. The communication environment is expanding.
[0003]
In addition, one of the communication applications of the IP network in the communication environment of such an always-on line is IP telephone communication. This IP telephone communication uses a technology called Voice over IP (VoIP) for realizing a voice call on an IP network, and its technical standard includes ITU-T Recommendation H.264. H.323, SIP (Session Initiation Protocol) defined by the IETF (Internet Engineering Task Force), and the like are applied.
[0004]
When this IP telephone communication is used, for example, when the same ISP is used in both terminals of a call, the communication cost can be significantly reduced as compared with a telephone using a public line.
[0005]
Also, facsimile communication using this VoIP has been proposed (see Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-41131 (Facsimile relay using Internet protocol addressing)
[0007]
In addition, by using a so-called IP telephone adapter, it is possible to use a conventional telephone for a public line to use IP telephone communication. Similarly, by using an IP telephone adapter, facsimile communication using VoIP can be realized using a conventional group 3 facsimile apparatus for public lines.
[0008]
[Problems to be solved by the invention]
In the IP network, data transmission is caused by queue waiting and processing delay in a router that is responsible for the relay function of the IP network, long packets in a thin access line, queue waiting in a storage and switching part, and temporary congestion. The speed fluctuates.
[0009]
Such fluctuations in the data transmission speed are absorbed by the buffer processing when decoding the packet into voice in the VoIP device. If the fluctuation is not absorbed, the voice packet is discarded in the VoIP device. For example, as described above, when a telephone for a public line or a group 3 facsimile apparatus is connected via an IP telephone adapter, a voice packet is discarded in the IP telephone adapter which is a VoIP device, and as a result, The voice quality is degraded due to the delay and discard of the voice packet, and a data error occurs in the group 3 facsimile communication.
[0010]
The present invention has been made in view of such circumstances, and has as its object to provide a group 3 facsimile apparatus that can perform appropriate communication even when connected to an IP network via an IP telephone adapter.
[0011]
[Means for Solving the Problems]
The present invention determines whether or not a designated destination is connected to an IP network when a call is made in a group 3 facsimile apparatus having an automatic calling function, and determines whether the destination is connected to an IP network. Is to limit the upper limit of the maximum modem speed applied in the pre-transmission procedure to a predetermined value.
[0012]
In a group 3 facsimile apparatus having an automatic calling function, it is determined whether or not a designated destination is connected to an IP network at the time of calling, and when the destination is connected to the IP network, a destination terminal is determined. Check the reported modem speed, and if the reported modem speed exceeds the preset modem speed upper limit, set the upper limit of the modem maximum speed to be applied in the pre-transmission procedure to the modem speed upper limit. On the other hand, if the modem speed notified from the partner terminal is smaller than the modem speed upper limit, the upper limit of the maximum modem speed applied in the pre-transmission procedure is set to the notified modem speed. It was made.
[0013]
In a group 3 facsimile apparatus having an automatic calling function, it is determined whether or not a designated destination is connected to an IP network at the time of calling, and when the destination is connected to the IP network, a destination terminal is determined. Check the notified modem speed.If the notified modem speed exceeds the modem speed upper limit set in advance for the destination, the upper limit of the modem maximum speed applied in the pre-transmission procedure is While the modem speed is limited to the modem speed upper limit, if the modem speed notified from the partner terminal is lower than the modem speed upper limit, the upper limit of the modem maximum speed applied in the pre-transmission procedure is changed to the notified modem speed. Is set to.
[0014]
The determination as to whether or not the specified destination is connected to the IP network is made based on whether or not a predetermined number of predetermined digits is added before the destination telephone number. When a predetermined number of digits is added before the destination telephone number, it is determined that the specified destination is connected to the analog public network, and the predetermined number of digits is added before the destination telephone number. If the predetermined number is not added, it is determined that the specified destination is connected to the IP network.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0016]
FIG. 1 shows an example of a communication system according to an embodiment of the present invention.
[0017]
In the figure, an analog telephone TL and a group 3 facsimile machine FX1 are connected inside the house of a VoIP adapter device (IP telephone adapter) ADP1, and an analog public line network PSTN is connected to the line side of the VoIP adapter device ADP1. And a line of the IP network NTp (for example, an ADSL line). The VoIP adapter device ADP1 connects the analog telephone TL1 and the group 3 facsimile device FX1 to the analog public telephone network PSTN or the IP network NTp so that a telephone call or group 3 facsimile communication can be performed.
[0018]
The analog PSTN PSTN and the IP network NTp are connected to each other via a gateway device GW, whereby the terminal device connected to the analog PSTN PSTN and the IP network NTp are connected to the IP network NTp. It is possible to communicate with a terminal device.
[0019]
A group 3 facsimile device FX2 is connected to the inside of the house of the VoIP adapter device ADP2, and a line of the IP network NTp is accommodated on the line side of the VoIP adapter device ADP2.
[0020]
Further, the group 3 facsimile apparatuses FX3 and FX4 are connected to the analog public switched telephone network PSTN.
[0021]
Here, for example, when the group 3 facsimile apparatus FX1 is connected to the IP network NTp via the VoIP adapter apparatus ADP1, it performs group 3 facsimile communication with the group 3 facsimile apparatus FX2 via the VoIP adapter apparatus ADP2. Alternatively, group 3 facsimile communication can be performed with the group 3 facsimile apparatus FX3 connected to the analog public switched telephone network PSTN via the gateway apparatus GW.
[0022]
Further, when the group 3 facsimile machine FX1 is connected to the analog PSTN PSTN via the VoIP adapter ADP1, the group 3 facsimile machine FX4 can perform group 3 facsimile communication with the group 3 facsimile machine FX4.
[0023]
Also, when the analog telephone TL or the group 3 facsimile machine FX1 places a call and adds the number “000” to the beginning of the telephone number when the VoIP adapter ADP1 makes a call, the VoIP adapter ADP1 selects the analog PSTN PSTN, When the telephone TL or the group 3 facsimile machine FX1 places a call and does not add the number "000" to the head of the telephone number, the IP network NTp is selected.
[0024]
Therefore, when making a call to the group 3 facsimile machine FX2 using the IP network NTp, the user of the group 3 facsimile machine FX1 designates the telephone number assigned to the group 3 facsimile machine FX2 as it is and makes a call. When a call operation is performed and a call is made to the group 3 facsimile machine FX4 connected to the analog public telephone network PSTN, the number "000" is prefixed to the telephone number assigned to the group 3 facsimile machine FX4. The calling operation is performed by designating in the added mode.
[0025]
On the other hand, in the case of the group 3 facsimile machine FX2, since the line to be connected is only the line of the IP network NTp, the calling operation is performed by directly specifying the destination telephone number.
[0026]
For example, when the group 3 facsimile machine FX1 calls the group 3 facsimile machine FX3 in a state where the IP network NTp is specified as a line, in this case, the user sets the group 3 facsimile machine FX3 as the destination telephone number. Make a call by specifying only the phone number assigned to. In this case, the routing function of the IP network NTp connects to the analog PSTN PSTN via the gateway device GW, and the group 3 facsimile machine FX3 is called.
[0027]
FIG. 2 shows a configuration example of the group 3 facsimile machine FX1 according to one embodiment of the present invention.
[0028]
In FIG. 1, a system control unit 1 performs a control process of each unit of the group 3 facsimile machine FX1 and a predetermined group 3 facsimile transmission control procedure process, and a system memory 2 is executed by the system control unit 1. And a work area of the system control unit 1. The parameter memory 3 is provided in the group 3 facsimile machine FX1. The clock circuit 4 is for storing various kinds of unique information, and is for outputting current time information.
[0029]
The scanner 5 is for reading a document image at a predetermined resolution, the plotter 6 is for recording and outputting an image at a predetermined resolution, and the operation display unit 7 is for operating this group 3 facsimile apparatus. And consists of various operation keys and various indicators.
[0030]
The encoding / decoding unit 8 encodes and compresses the image signal and decodes the encoded and compressed image information into the original image signal. The image storage device 9 encodes and compresses the image signal. This is for storing a large number of image information in the closed state.
[0031]
The group 3 facsimile modem 10 is for realizing the modem function of the group 3 facsimile, and is a low-speed modem function (V.21 modem) for exchanging a transmission procedure signal, and mainly for exchanging image information. It has a high-speed modem function (V.17 modem, V.34 modem, V.29 modem, V.27ter modem, etc.).
[0032]
The network control device 11 is for connecting the group 3 facsimile device FX1 to the VoIP adapter device ADP1 and has an automatic transmission / reception function.
[0033]
These are a system control unit 1, a system memory 2, a parameter memory 3, a clock circuit 4, a scanner 5, a plotter 6, an operation display unit 7, an encoding / decoding unit 8, an image storage device 9, a group 3 facsimile modem 10, and , The network controller 11 is connected to an internal bus 12, and data exchange between these elements is mainly performed through the internal bus 12.
[0034]
Data exchange between the network control device 11 and the group 3 facsimile modem 10 is directly performed.
[0035]
FIG. 3 shows an example of a group 3 facsimile transmission procedure.
[0036]
In the figure, the calling side first calls the called side, and when the called side responds to the incoming call, the calling side sends out a signal CNG, which is a predetermined tone signal, to the called side. Upon receiving the signal CNG, the called side responds to the calling side with a signal CED (called station identification signal), which is a predetermined tone signal, and a signal DIS (digital identification) for notifying the function of the terminal itself. Signal) to the calling party. At this time, the called side can send out a signal CSI (called terminal identification) to notify the calling side of the identification information of its own terminal.
[0037]
Upon receiving the signal DIS (and the signal CSI), the calling party examines the receiving capability of the called party, and determines the size, line density, coding scheme, and modem speed to be used of the transmission image information, A signal DCS (digital command signal) for notifying the determined content is sent to the called side. At this time, the calling side can transmit a signal TSI (transmission terminal identification) to notify the called side of the identification information of the own terminal. Further, the calling side can transmit a signal SID (transmitter identification) to notify the called side of a password for authentication. Further, the calling side can send a signal SUB (sub address) to indicate a transfer destination or the like. In addition, the calling side can transmit a signal IRA (Internet Routing Address) (not shown) to designate a transfer destination address on the Internet. Transmission of the signals SID, SUB, TSI, and IRA is optional.
[0038]
Next, the calling side sends a signal TCF (training check) to the called side in order to perform modem training at the modem speed notified by the signal DCS. Upon receiving the signal TCF, the called side checks whether a reception error has occurred. If not, the called side notifies the calling side of a signal CFR (reception preparation confirmation).
[0039]
As a result, the calling side obtains image information PIX1 of the first page obtained by encoding and compressing the image data of the first page of the paper size and the line density notified by the signal DCS using the encoding method designated by the signal DCS. To the called party. When the transmission of the image information for one page is completed, in this case, since a subsequent page exists, a signal MPS (multi-page signal) is sent to the called side as a post-message signal. The image data is created by starting the scanner 5 at that time and reading and inputting the original image of the first page, or by notifying the stored image information of the first page stored in advance to the notified paper size and line density. And creating image data for transmission. The same applies to creation of image information.
[0040]
When receiving the image information PIX1 of the first page, the called side detects a reception error, and when receiving the post-message signal, if there is no reception error in the image information PIX1 of one page received at that time, , A signal MCF (message confirmation) to the calling side.
[0041]
Thereby, the calling side transmits the image information PIX2 of the second page. The image information PIX2 is of the same size, line density, and coding method as the image information PIX1. In this case, when the transmission of the image information PIX2 ends, in this case, since there is no subsequent page, a signal EOP (end of procedure) is sent to the called side as a post-message signal.
[0042]
When receiving the image information PIX2 of the second page, the called side detects a reception error, and when receiving the post-message signal, if there is no reception error in the image information PIX2 of one page received at that time. , Signal MCF to the calling party.
[0043]
As a result, the calling side sends a signal DCN (disconnect command) to the called side to restore the line. When the called side receives the signal DCN, it restores the line.
[0044]
FIG. 4 shows an example of an operation performed by the group 3 facsimile machine FX1 when making a call.
[0045]
First, the user sets a document to be transmitted on the scanner 5 (process 101), operates the operation display unit 7, and inputs a destination telephone number (process 102). At this time, when the destination is connected to the IP network NTp, the user inputs only the telephone number assigned to the destination, and when the destination is connected to the analog public switched telephone network PSTN, A telephone number with the number “000” added to the beginning of the telephone number assigned to the destination is input.
[0046]
When the user operates a start key (not shown) of the operation display unit 7 to instruct transmission start (YES in the determination 103), the system control unit 1 uses the network control device 11 to call the destination. (Step 104), and receives the signal DIS from the partner terminal (Step 105).
[0047]
Here, it is checked whether or not the destination at this time is connected to the IP network NTp based on the contents of the telephone number of the destination input in the process 102. That is, if the number "000" is added at the beginning, it is determined that the connection is made to the analog PSTN PSTN. If the number "000" is not added at the beginning, the IP network NTp is connected. Judge that it is connected.
[0048]
If the destination is connected to the IP network NTp and the result of determination 106 is YES, the modem speed is set to a predetermined low speed (for example, 9600 bps or 4800 bps) (process 107). Further, other communication conditions such as the paper size are appropriately set.
[0049]
Then, a signal DCS for notifying communication conditions such as the set modem speed is transmitted to the partner terminal (process 108). Subsequently, a predetermined modem training procedure is performed at the modem speed set at that time, and the modem speed to be used at that time is determined with the partner terminal (process 109).
[0050]
Next, a predetermined image information transmission procedure for transmitting the image information of the original image set on the scanner 5 is performed (step 110). When this image information transmission is completed, the line is restored (step 111) and a series of transmissions is performed. The call operation ends.
[0051]
If the destination is not connected to the IP network NTp and the result of the determination 106 is NO, the modem is selected according to a predetermined selection method from the relationship between the modem speed of the own terminal and the modem speed available to the other terminal. The speed is set (process 112). Further, other communication conditions such as the paper size are appropriately set.
[0052]
Next, the process proceeds to a process 108, where the subsequent processes are executed to perform an operation at the time of calling.
[0053]
In this manner, in this embodiment, when the destination is connected to the IP network NTp, the modem speed is set to a predetermined low speed to perform the modem training procedure. It is less susceptible to data errors caused by packet delays and discards that occur, and as a result, it is possible to suppress occurrence of data reception errors at destinations and to perform smooth facsimile communication.
[0054]
FIG. 5 shows another example of the operation performed by the group 3 facsimile machine FX1 when making a call.
[0055]
First, a user sets a transmission original on the scanner 5 (process 201), operates the operation display unit 7, and inputs a destination telephone number (process 202). At this time, when the destination is connected to the IP network NTp, the user inputs only the telephone number assigned to the destination, and when the destination is connected to the analog public switched telephone network PSTN, A telephone number with the number “000” added to the beginning of the telephone number assigned to the destination is input.
[0056]
When the user operates a start key (not shown) of the operation display unit 7 to instruct transmission start (the result of the determination 203 is YES), the system control unit 1 uses the network control device 11 to call the destination. (Step 204), and receives the signal DIS from the partner terminal (Step 205).
[0057]
Here, it is checked whether or not the destination at this time is connected to the IP network NTp based on the contents of the telephone number of the destination input in the process 202. That is, if the number "000" is added at the beginning, it is determined that the connection is made to the analog PSTN PSTN. If the number "000" is not added at the beginning, the IP network NTp is connected. Judge that it is connected.
[0058]
If the destination is connected to the IP network NTp and the result of the determination 206 is YES, the maximum speed of the modem speed notified from the partner terminal is checked (process 207), and a value equal to or more than a predetermined lower limit is set. It is checked whether or not (decision 208). Here, the set lower limit is, for example, 9600 bps or 4800 pbs.
[0059]
When the result of the judgment 208 is YES, the modem speed is set to a predetermined low speed (for example, 9600 bps or 4800 bps) (process 209). Further, other communication conditions such as the paper size are appropriately set.
[0060]
Then, a signal DCS for notifying the communication conditions such as the set modem speed is transmitted to the partner terminal (process 210). Subsequently, a predetermined modem training procedure is performed at the modem speed set at that time, and the modem speed to be used at that time is determined with the partner terminal (process 211).
[0061]
Next, a predetermined image information transmission procedure for transmitting image information of the document image set on the scanner 5 is performed (step 212). When the image information transmission is completed, the line is restored (step 213), and a series of transmissions is performed. The call operation ends.
[0062]
When the destination is connected to the IP network NTp and the result of the judgment 208 is NO when the maximum speed of the modem speed notified from the partner terminal is less than the set lower limit, and when the destination is the IP network NTp. If the connection is not established and the result of the determination 206 is NO, the modem speed is set according to a predetermined selection method from the relationship between the modem speed of the own terminal and the modem speed usable by the partner terminal (process 214). . Further, other communication conditions such as the paper size are appropriately set.
[0063]
Next, the process proceeds to a process 210, where the subsequent processes are executed to perform the operation at the time of calling.
[0064]
As described above, in the present embodiment, when the destination is connected to the IP network NTp, and when the maximum speed of the modem speed notified from the partner terminal is equal to or higher than the predetermined lower limit, the modem speed is changed to the predetermined speed. Since the modem training procedure is performed with the lower limit set, the packet is less susceptible to data errors caused by packet delays and discards occurring in the IP network NTp. The occurrence of a reception error can be suppressed, and smooth facsimile communication can be performed.
[0065]
By the way, in the above-described embodiment, one set lower limit is used, but the set lower limit can be set for each destination. In this case, for example, a maximum communication speed lower limit setting information table as shown in FIG. 6A is provided. This maximum communication speed lower limit setting information table is a collection of a plurality of maximum communication speed lower limit setting information, and each of the maximum communication speed lower limit setting information is, as shown in FIG. (Telephone number) and a lower limit of the maximum communication speed set for the destination.
[0066]
FIG. 7 shows still another example of the operation performed by the group 3 facsimile machine FX1 when making a call.
[0067]
First, the user sets a transmission original on the scanner 5 (process 301), operates the operation display unit 7, and inputs a destination telephone number (process 302). At this time, when the destination is connected to the IP network NTp, the user inputs only the telephone number assigned to the destination, and when the destination is connected to the analog public switched telephone network PSTN, A telephone number with the number “000” added to the beginning of the telephone number assigned to the destination is input.
[0068]
When the user operates a start key (not shown) of the operation display unit 7 to instruct transmission start (the result of the determination 303 is YES), the system control unit 1 uses the network control device 11 to call the destination. (Step 304), and receives the signal DIS from the partner terminal (Step 305).
[0069]
Here, it is checked whether or not the destination at this time is connected to the IP network NTp based on the contents of the telephone number of the destination input in the process 302. That is, if the number "000" is added at the beginning, it is determined that the connection is made to the analog PSTN PSTN. If the number "000" is not added at the beginning, the IP network NTp is connected. Judge that it is connected.
[0070]
If the destination is connected to the IP network NTp and the result of the determination 306 is YES, the maximum communication speed lower limit corresponding to the telephone number of the destination at that time is obtained from the maximum communication speed lower limit setting information table. (Step 307). Then, the maximum modem speed notified by the partner terminal is checked (process 308), and it is checked whether the maximum modem speed is equal to or higher than the maximum communication speed lower limit (determination 309).
[0071]
If the result of decision 309 is YES, the modem speed is set to the maximum communication speed lower limit (process 310). Further, other communication conditions such as the paper size are appropriately set.
[0072]
Then, a signal DCS for notifying communication conditions such as the set modem speed is transmitted to the partner terminal (process 311). Subsequently, a predetermined modem training procedure is performed at the modem speed set at that time, and the modem speed to be used at that time is determined with the partner terminal (process 312).
[0073]
Next, a predetermined image information transmission procedure for transmitting image information of the document image set on the scanner 5 is performed (step 313). When the image information transmission is completed, the line is restored (step 314), and a series of transmissions is performed. The call operation ends.
[0074]
When the destination is connected to the IP network NTp and the maximum modem speed notified from the partner terminal is less than the maximum communication speed lower limit obtained in the process 307, and the result of the judgment 309 is NO, If the destination is not connected to the IP network NTp and the result of the determination 306 is NO, the modem is selected according to a predetermined selection method from the relationship between the modem speed of the own terminal and the modem speed available to the other terminal. The speed is set (process 315). Further, other communication conditions such as the paper size are appropriately set.
[0075]
Next, the process proceeds to a process 311 to execute the subsequent processes to perform the operation at the time of calling.
[0076]
In this way, in this embodiment, since the maximum communication speed lower limit value is set for each destination, it is possible to set an appropriate modem speed according to the connection environment of the destination, and a smoother group 3 facsimile is possible. Communication can be performed.
[0077]
By the way, in the above-described embodiment, the group 3 facsimile apparatus FX1 connected to the VoIP adapter apparatus ADP1 has been described. However, the group 3 facsimile apparatus FX2 connected to the VoIP adapter apparatus ADP2 performs the same processing at the time of transmission. However, in the case of the group 3 facsimile machine FX2, since there is no line switching, it is always connected to the IP network NTp.
[0078]
Further, in the above-described embodiment, the VoIP adapter device ADP1 checks the content of the selection signal output from the terminal connected to the inside of the house, and places a predetermined number (“000” in the above-described embodiment) at the top of the selection signal. Is added, it is determined that a network other than the IP network (in this case, the analog public switched telephone network PSTN) is selected, and if a predetermined number is not added to the head of the selection signal, the IP network is selected. Is determined to have been selected, but other methods can be applied for such a method of determining the designation of the line to be used.
[0079]
【The invention's effect】
As described above, according to the present invention, when the destination is connected to the IP network, the modem speed is set to a predetermined low speed to perform the modem training procedure. It is less susceptible to data errors caused by packet delays and discards that occur, and as a result, it is possible to suppress the occurrence of data reception errors at the destination and to perform smooth facsimile communication. Get.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of a communication system according to one embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration example of a group 3 facsimile machine FX1 according to one embodiment of the present invention.
FIG. 3 is a time chart showing an example of a group 3 facsimile transmission procedure.
FIG. 4 is a flowchart showing an example of an operation performed by the group 3 facsimile machine FX1 when making a call.
FIG. 5 is a flowchart showing another example of the operation performed by the group 3 facsimile machine FX1 when making a call.
FIG. 6 is a schematic diagram showing an example of a maximum communication speed lower limit setting information table.
FIG. 7 is a flowchart showing still another example of the operation performed by the group 3 facsimile machine FX1 when making a call.
[Explanation of symbols]
FX1, FX2, FX3, FX4 Group 3 facsimile machine NTp IP network ADP1, ADP2 VoIP adapter device

Claims (5)

In a group 3 facsimile machine with automatic calling function,
At the time of calling, it is determined whether or not the specified destination is connected to the IP network. If the destination is connected to the IP network, the upper limit of the maximum modem speed applied in the pre-transmission procedure is determined. A group 3 facsimile apparatus characterized by limiting to a predetermined value. In a group 3 facsimile machine with automatic calling function,
When a call is made, it is determined whether or not the designated destination is connected to the IP network. If the destination is connected to the IP network, the modem speed notified by the partner terminal is checked. If the speed exceeds the preset modem speed upper limit, the upper limit of the modem maximum speed applied in the pre-transmission procedure is limited to the modem speed upper limit, while the modem speed notified from the partner terminal is A group 3 facsimile apparatus, wherein when the modem speed is lower than the modem speed upper limit value, the modem speed upper limit value applied in the pre-transmission procedure is set to the notified modem speed. In a group 3 facsimile machine with automatic calling function,
When a call is made, it is determined whether or not the designated destination is connected to the IP network. If the destination is connected to the IP network, the modem speed notified by the partner terminal is checked. If the speed exceeds the modem speed upper limit set in advance for the destination, the upper limit of the maximum modem speed applied in the pre-transmission procedure is limited to the modem speed upper limit, and the other terminal notifies the upper limit. If the modem speed is lower than the modem speed upper limit value, the upper limit value of the modem maximum speed applied in the pre-transmission procedure is set to the notified modem speed. The method according to claim 1, wherein the determination as to whether the designated destination is connected to an IP network is performed based on whether a predetermined number of a predetermined number of digits is added before the destination telephone number. The group 3 facsimile apparatus according to claim 2 or 3. If a predetermined number of predetermined digits is added before the destination telephone number, it is determined that the specified destination is connected to the analog public network, and a predetermined number of predetermined digits is specified before the destination telephone number. 5. The group 3 facsimile apparatus according to claim 4, wherein when the number is not added, it is determined that the designated destination is connected to an IP network.

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