JP2820155B2 - Control method of data terminal device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for a data terminal device capable of determining whether a recall is possible and a recall time.

[Prior art] In a data terminal device using a data communication network such as ISDN (Digital Integrated Communication Network) or PSPDN (Packet Switched Network) as a transmission path, during a procedure until a call is set up with a partner terminal,
Alternatively, if any failure occurs in the data communication network or the partner terminal during data transmission performed after the call connection is terminated, a predetermined procedure signal is returned from the data communication network or the partner terminal, and the requested call is established. Not established or established call is disconnected.

As described above, when the call is not established or the call is disconnected, the calling data terminal device re-calls the same partner terminal and transmits the transmission information set in the data transmission operation to the partner terminal. Try to send to.

If all transmission information cannot be transmitted by one re-call, the re-call is repeated up to a specified number of times, and all the remaining transmission information is transmitted to the partner terminal.

[Problems to be Solved by the Invention] However, when the call is not established or the call is disconnected, the call may not be established or the call may be disconnected again depending on the situation of the network or the partner terminal. .

In the past, since recall conditions were not specifically defined, when a call was not established or a call was disconnected, a recall operation was always performed. Even when a failure occurs and there is no possibility that the call can be established, re-calling to the partner terminal is repeatedly performed, which may cause a problem of performing an unnecessary call operation.

Therefore, an object of the present invention is to provide a control method of a data terminal device capable of determining whether or not a recall can be made and a recall time interval when a recall is made.

[Means for Solving the Problems] The present invention relates to a method for controlling a data terminal device using ISDN as a transmission path, wherein when a call disconnection message is received during a call setup procedure or during data transmission, the call disconnection message is transmitted. Based on the contents of the included reason display information element, whether or not a recall is possible and the recall interval time are determined, and the cause of the call disconnection is determined and visually displayed.

Also, in the control method of a data terminal device for transmitting data in the packet switching mode, when a call disconnection packet is received during a call setup procedure or during data transmission, the content of the call progress signal included in the call disconnection packet is changed. On the basis of this, it is determined whether or not a re-call can be made and the re-call interval time, and the cause of the call disconnection is determined and visually displayed. Further, when the content of the call progress signal is "network connection regulated", the re-call interval time is set to a longer value.

[Operation] Therefore, since a re-call operation can be performed according to the situation of the data communication network and the partner terminal, useless calling operation is prevented.

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

FIG. 1 shows a group 4 facsimile apparatus according to an embodiment of the present invention.

The system control section 1 performs processing for controlling the operation of each section of the group 4 facsimile apparatus.
The system memory 2 stores a control processing program to be executed by the system control unit 1 and various constants necessary for executing the control processing program, and constitutes a work area of the system control unit 1.
The parameter memory 3 stores various data unique to the group 4 facsimile apparatus, for example, a file management table (described later). The parameter memory 3 is backed up by a battery.

The scanner 4 is for reading a document image at a predetermined resolution, and the plotter 5 is for recording and outputting an image at a predetermined resolution.

The operation display unit 6 is used to operate the group 4 facsimile apparatus, and includes various operation keys such as numeric keys and one-touch dial keys, and various display devices such as a liquid crystal display.

The encoding / decoding unit 7 encodes and compresses the image signal and decodes the encoded and compressed image information into the original image signal.

The image storage device 8 stores an image signal file and an image information file, and is composed of a large-capacity external storage device.

The ISDN interface circuit 9 is for connecting the ISDN to the facsimile apparatus, and the layer 1 signal control section 10 is for controlling the signal of the ISDN layer 1, and is mainly used for call control. It also has a function of separating / integrating a D-channel (signal channel) signal used and a B-channel (information channel) signal used for data transmission.

The D channel transmission control unit 11 is for performing ISDN call setting control using the D channel and transmission control processing for packet transmission. The B channel transmission control units 12 and 13 Is used to perform a transmission control process for data transmission performed by using. Further, the B-channel transmission control units 12 and 13 also have a packet transmission function.

System control unit 1, system memory 2, parameter memory 3, scanner 4, plotter 5, operation display unit 6, encoding / decoding unit 7, image storage device 8, D-channel transmission control unit
11 and the B-channel transmission control units 12 and 13 are connected to a system bus 14, respectively, and various types of data such as control information and transmission data between these elements are exchanged via the system bus 14. Done.

The two B-channel signals and the D-channel signals on the ISDN are transmitted to the layer 1 signal control unit 10 and the B channel transmission control units 12 and 13 and the layer 1 signal control unit 10 and the D channel transmission control unit 11 respectively. Are exchanged between them.

FIG. 2 shows an example of the file management table FMT stored in the parameter memory 3. The file management table FMT is for storing various kinds of information necessary for performing the set image information transmission, and one is set for each image information transmission.

In the figure, the file number FNO is for identifying each file management table FMT, and the call time information CTM represents a call time or a recall time specified by the operator. The destination number information CNO indicates the ISDN number of the destination, and the switching method information SMD is for storing whether the switching method for connecting to the destination is the circuit switching mode or the packet switching mode.

The transmission mode information MDD is for storing the transmission function specified by the operator, and includes transmission result information RES.
Is for storing the result of the image information transmission managed by the file management table FMT, and indicates that a call or recall operation is being performed. "Send O", indicating that the message was received normally
Either "K" or "transmission NG" indicating that the destination failed to normally receive the image information is set as the content.

The number-of-calls information CLT is for storing the number of calls, and the transmission end page number information EPG is for storing the last page number of the pages that can be normally transmitted to the destination. The number information PGN is for storing the number of originals to be transmitted, and includes page map information MPG.
Is for storing the arrangement status of the storage area occupied by the image information in the image storage device 8 in page units.

The file management table FMT is formed when the operator performs an operation for setting image information transmission and the scanner 4 finishes reading the image of the transmission original, and is stored in the parameter memory 3.

FIG. 3 (a) shows an example of a call control procedure with the ISDN in the circuit switching mode.

That is, the calling terminal first sets the circuit switching mode as the transfer mode, sends a call setup message SETUP specifying the destination terminal to the ISDN, and requests a call setup with the destination terminal, and the ISDN A call setup message SETUP is sent to the called terminal to make a call. In addition, ISDN includes a call setting acceptance message CALL_PRO for notifying the call setting status.
Send C to the calling terminal.

Upon detecting an incoming call, the called terminal sends out a calling message ALERT to ISDN continuously at a predetermined interval when the own terminal is in a state where it can receive a call.
T is transmitted to the calling terminal to notify that calling of the called terminal has started.

When the called terminal answers the incoming call, the response message CONN is sent to ISDN.
ISDN sends a response message CONN to the calling terminal to notify that the called terminal has accepted the call.

Also, ISDN sends a response confirmation message CONN_ACK to the called terminal.
To confirm the response of the called terminal, at which point an information channel (B channel) for data transmission is established between the calling terminal and the called terminal.

Thus, data transmission using the information channel is performed between the calling terminal and the called terminal according to the transmission control procedure set to the traditional function of each terminal.

When the data transmission is completed, the originating terminal sends a disconnection message DISC to the ISDN to request release of the information channel, and the ISDN sends a disconnection message DISC to the destination terminal to notify the destination of the restoration of the information channel.

As a result, when the destination terminal responds to the ISDN with a release message REL for notifying the completion of the channel disconnection, the release message REL is transmitted from the ISDN to the calling terminal. When the channel release is completed, the calling terminal issues a release completion message REL_COMP to the ISDN.
To notify that fact, ISDN sends a release completion message REL_COMP to the destination terminal, the release of the information channel is established, and the information channel set between the calling terminal and the destination terminal Is completely released.

Thus, the information channel between the calling terminal and the called terminal is set, data transmission is performed, and when the data transmission ends, the information channel is released.

When the called terminal cannot answer the incoming call, as shown in FIG. 3B, when receiving the call setup message SETUP from the ISDN, the called terminal responds to the ISDN with a release completion message REL_COMP including the reason why the incoming call cannot be answered.

Thereby, the ISDN sends a release message REL including the reason included in the release completion message REL_COMP received from the destination terminal at that time to the calling terminal, whereby the calling terminal responds with the release completion message REL_COMP, Release the call.

Also, when ISDN rejects a call from a calling terminal,
As shown in FIG. 11C, a release completion message REL_COMP including the reason for the rejection is returned to the calling terminal. As a result, the calling terminal releases the call. Further, during the data transmission on the B channel, there may be a case where some trouble occurs and the ISDN disconnects the call. In this case, the ISDN sends a disconnection message DISC including the reason for the disconnection to each terminal. , Restore the call.

In this way, when the call connection is rejected in the circuit switching mode and when the established communication path is disconnected, the release completion message REL_COMP and the release message RE
L or a type (part) of an information element (reason display information element) indicating a reason included in the disconnection message DISC;
Table 1 shows an example of the possibility of recall and an example of the recall interval time.

FIG. 4A shows an example of a call control procedure with the ISDN in the packet switching mode. This example procedure is based on the IS
Indicates that the DN has a packet control function (packet handler).

First, the calling terminal sends a call setup message SETUP specifying the transfer mode to the packet mode to ISDN.

As a result, ISDN activates the packet control function, responds to the calling terminal with a call setup acceptance message CALL_PROC, sends a response message CONN to the calling terminal, and sets up an information channel communication path with the calling terminal. .

In this way, when receiving the information channel assignment, the calling terminal sends out a calling packet CR to ISDN with the destination terminal's ISDN address set as the destination address.

Accordingly, ISDN recognizes the called terminal, and sets the use channel to the B or D channel and the communication mode setting to the packet mode for the called terminal, and sends the call setup message SETUP to the called terminal. Send out.

Thereby, for example, when the receiving terminal responds to the response message CONN in which the use channel is set to the D channel, the ISDN
Sets the D channel to the communication path, and sends out the called packet CN to the called terminal.

As a result, when the call receiving packet CA is answered from the called terminal, the ISDN sends a connection completion packet CC to the calling terminal, whereby a packet communication path is set between the calling terminal and the called terminal. .

Thereafter, a data transfer phase is executed according to a transmission procedure defined between the calling terminal and the called terminal, and the transmission file is transmitted from the calling terminal to the called terminal.

Then, when the data transfer phase is completed, the calling terminal sends a recovery request packet CQ to ISDN to request a release of the communication path with the called terminal, and the ISDN sends a disconnection instruction CI packet to the called terminal.

Thereby, the destination terminal sends a disconnection confirmation packet CF to the access unit in order to release the communication path,
The access unit sends a recovery confirmation packet CF to the calling terminal.

In this way, when the packet communication path between the calling terminal and the destination terminal is released and the communication path between the calling terminal and the access unit is released, the calling terminal next sends the disconnect message DISC to the ISDN. To request the release of the information channel, whereby ISDN sends a disconnection message DISC to the terminating terminal to notify of the recovery of the information channel.

As a result, when the destination terminal responds to the ISDN with the release message REL, the release message REL is transmitted from the ISDN to the calling terminal. The calling terminal sends the release completion message REL_COMP to ISDN
, So that the ISDN releases the release complete message REL_
The COMP sends the COMP to the called terminal, thereby completely releasing the information channel established between the calling terminal and the called terminal.

Thus, an information channel is set between the calling terminal and the called terminal, a packet communication path is set on the information channel, and packet mode data transmission is performed using the packet communication path. When the data transmission is completed, the packet communication path and the information channel are sequentially released.

When the called terminal cannot answer the incoming call, as shown in FIG. 3B, when receiving the call setup message SETUP from the ISDN, the called terminal responds to the ISDN with a release completion message REL_COMP including the reason why the incoming call cannot be answered.

Thereby, the ISDN sends the disconnection packet CI including the reason included in the release completion message REL_COMP received from the destination terminal at that time to the source terminal, so that the source terminal can release the communication path in order to release the communication path. Disconnect confirmation packet CF
Is transmitted to the ISDN. Thereafter, the information channel between the ISDN and the calling terminal is released and the call is restored in the same manner as in FIG.

Further, when the ISDN rejects the call, as shown in FIG. 10C, a disconnection instruction packet CI including the rejection reason is transmitted to the call packet CR transmitted from the calling terminal.

As a result, the calling terminal can release the communication path, release the information channel, and
Perform call recovery.

In the packet switching mode, if the communication path cannot be maintained for any reason such as a failure in the data transfer phase, ISDN sends a reset instruction packet containing the reason for disconnection to each terminal. RI or restart instruction packet SI is transmitted.
Thereby, each terminal disconnects the communication path with ISDN and recovers the call.

As described above, in the packet switching mode, the relation between the reason (call progress signal) included in the disconnection instruction packet CI, the reset instruction packet RI, or the restart instruction packet RI for disconnecting the call, and the type of the reissued call Is shown in Table 2 below.

The relationship between Table 1 and Table 2 described above is stored in the parameter memory 3.

With the above configuration, the operator sets the transmission original on the scanner 4, operates the operation display unit 6, inputs the destination number, the exchange method, and the transmission function used at that time, and starts the transmission operation. And the system control unit 1
The scanner 4 performs a reading operation to read a transmission original set at that time, encodes and compresses an image signal obtained thereby by the encoding / decoding unit 7, and stores the obtained image information in the image storage device 8. accumulate.

When the accumulation of the image information is completed, the system control unit 1
Forms the above-mentioned file management table FMT for the transmission image file and stores it in the parameter memory 3. If the calling time is specified at this time, the specified time is set as calling time information CTM. If the time is not specified, the calling time information CTM is set.
The operation time at that time is set in M. The transmission result information RES indicates “calling” and the transmission end page number information E
“0” is set in PG.

On the other hand, when one or more B-channel transmission control units 12 and 13 are in a usable state, the system control unit 1 performs the transmission processing shown in FIGS. Execute

That is, it is checked whether or not there is at least one file management table FMT in which "calling" is set in the contents of the transmission result information RES (decision 101), and when the result of the decision 101 is YES, it corresponds. File management table FMT
Out of the file management table FMT in which the time before the current time is set in the contents of the call time information CTM,
It is checked whether there is more than one (decision 102). If the result of decision 102 is YES, the corresponding file management table F
One of the MTs is selected (process 103).

Then, the value of the number-of-calls information CLT of the selected file management table FMT is incremented by one (process 104), and it is checked whether the value of the number-of-calls information CLT has exceeded the limit value of the number of calls (decision). 105).

If the result of the determination 105 is YES, the number of recalls has exceeded the limit value, so "transmission NG" is set in the transmission result information RES of the file management table FMT (processing 106).
The transmission processing ends.

When the result of the determination 105 is NO, the calling operation can be continued, and it is checked whether or not the packet exchange mode is set in the exchange mode information SMD of the file management table FMT (decision 107).

When the result of the determination 107 is YES, the above-described packet mode call setup procedure is executed with ISDN (process 108).
The B channel is established (step 109), and the B channel layer 2
To establish the B-channel layer 2
110).

Then, a call request packet C in which the content of the destination number information CNO of the file management table FMT is set as the destination
R is sent to ISDN to call the destination (process 111), and a response from ISDN is received (process 112).

It identifies whether the received response is the connection completion packet CC or the disconnection instruction packet CI (decisions 113 and 114). If the received response is neither the connection completion packet CC nor the disconnection instruction packet CI, and the result of the determination 114 is NO, the process ends with an error (process 115) and ends the transmission process.

Here, when the disconnection instruction packet CI is received (the result of the determination 114 is YES), the contents of the call progress signal included in the disconnection instruction packet CI are checked to identify the cause (process 116), and the image information is transmitted. Cannot do, and,
The contents of the cause are displayed and output from the operation display unit 6 (process 11).
7) The calling time resetting process (process 118: subroutine) is executed in a state where the content of the recurring call type corresponding to the content of the call progress signal is set as an argument.

In the calling time resetting process, as shown in FIG.
At that time, the recalling type given as an argument is "OK", "LONG OK", "UNKNOWN", or "NO"
Judge which of the above applies (judgments 201, 202, 20
3).

If the recall type is "OK", the decision 201
When the result of step S1 is YES, the content of the call time information CTM of the file management table FMT selected at that time is set to 10
After a change of seconds (process 204), the process returns to the original process.

If the recall type is "LONG OK" and the result of determination 202 is YES, the content of the call time information CTM is changed after 60 seconds (process 205), and the process returns to the original process.

If the recall type is "unknown" and the result of determination 203 is YES, the content of the call time information CTM is changed after 180 seconds (process 206), and the process returns to the original process.

If the recall type is "impossible" and the result of determination 203 is NO, the content of the transmission result information RES of the file management table FMT selected at that time contains "transmission NG".
Is set (process 207), and the process returns to the original process.

In this way, when the calling time is reset, the B channel release procedure is executed to release layers 3 and below (processing 11).
9), the call is restored (process 120), and this calling process ends.

When the packet received in the process 112 is the connection completion packet CC and the result of the judgment 113 is YES, the image information pre-procedure is executed, and the transmission function is discussed with the partner terminal as necessary (processing 121), transmission end page number information E of the file management table FMT selected at that time
A value obtained by adding 1 to the PG value is set as a variable CPN for managing the page number to be transmitted (process 122).

Then, based on the content corresponding to the (CPN) page of the page map information MPG of the file management table FMT selected at that time, the image information of the (CPN) page is read out by the image storage device 8, and the destination is read. Send to (Process
one two Three). At this time, every time one transmission unit is transmitted, it is monitored whether the page ends or whether any of the disconnection instruction packet CI, the restart instruction packet SI, and the reset instruction packet RI is received from ISDN. (NO loop of judgments 124 and 125).

When the transmission of the image information for one page is completed and the result of determination 124 is YES, the value of the variable CPN at that time is the value of the page number information PGN of the file management table FMT selected at that time. It is checked whether or not the above has been reached (decision 126).

When the result of the determination 126 is NO, since there is a subsequent page, a procedure signal for notifying the partner terminal of the end of the page is sent (process 127), and the partner terminal responds to the signal of the page by the signal responded from the partner terminal. It is checked whether or not the message has been received normally (decision 128).

When the other terminal receives data normally and the result of determination 128 is YES, the value of the variable CPN and the value of the transmission end page number information EPG of the file management table FMT selected at that time are each increased by one. (Process 129), Process 123
Then, the image information of the next page is transmitted.

If the other terminal cannot receive the data normally,
When the result of NO is NO, the B channel is released to temporarily end the image information transmission (process 130), the call is restored (process 131), a transmission error has occurred, and
The generated page number is displayed and output from the operation display unit 6 to notify the operator of that (step 132), and the call time information CTM of the file management table FMT selected at that time.
Is changed to 180 seconds (process 133), and this transmission process ends.

When all pages have been transmitted and the result of determination 126 is YES, the document has ended, so a procedure signal for notifying the end of the document is sent to the partner terminal (process 134), and a response is made from the partner terminal. The signal checks whether the other terminal has received the last page normally (decision 135).

If the other terminal has received normally and the result of the determination 135 is YES, “transmission OK” is set in the transmission result information RES of the file management table FMT selected at that time (processing 136), and B The channel is released (process 137), the call is restored (process 138), and this communication process ends.

If the result of the determination 135 is NO in a case where the other terminal has not been able to normally receive, the processing shifts to the processing 130.

Further, during the transmission of the image information, when any of the disconnection instruction packet CI, the restart instruction packet SI, or the reset instruction packet RI is received, and the result of the determination 125 is YES, the received disconnection instruction packet The cause is identified by examining the contents of the call progress signal contained in the CI, restart instruction packet SI, or reset instruction packet RI (process 139), image information cannot be transmitted, and the cause of the cause is manipulated. The display is output from the display unit 6 (processing 140), and the processing 118 is performed in a state where the details of the recall type corresponding to the contents of the call progress signal are set as arguments.
Move to

On the other hand, when the circuit switching mode is set as the switching method and the result of the determination 107 is NO, a call setup message SETUP based on the contents of the file management table FMT selected at that time is sent to ISDN. A destination is called (process 141), and a response from ISDN is received (process 142).

Then, it is determined whether the content of the response received at that time is a response message CONN, a release message REL, a release completion message REL_COMP, or another message (decisions 143, 144, 145).

If the received content is not any of the response message CONN, the release message REL, and the release completion message REL_COMP (result of the determination 145 is NO), a process corresponding to the received message is performed (process 146). Returning to the processing 142, the response message CONN, the release message RE
L and any of the release completion messages REL_COMP are received.

Upon receiving the release message REL, the result of the decision 144 is YES.
, The reason display information element included in the release message REL is identified, the cause of disconnection is identified (process 147), image information cannot be transmitted, and
The contents of the cause are displayed and output from the operation display unit 6 (processing 14).
8) The calling time resetting process (process 149: subroutine) is executed in a state where the re-calling type content corresponding to the content of the reason display information element is set as an argument.

Then, a release completion message REL_COMP is transmitted to ISDN (process 150), and the transmission process ends.

Also, receive the release completion message REL_COMP and make a judgment.
When the result of step 145 is YES, the cause of disconnection is identified based on the contents of the reason display information element included in the release completion message REL_COMP (processing 151), and image information cannot be transmitted, and the contents of the cause Is output from the operation display unit 6 (process 152), and the call time resetting process (process 153: subroutine) is executed in a state where the recall type content corresponding to the content of the reason display information element is set as an argument. Then, the transmission processing ends.

When the response message CONN is received and the result of the determination 143 is YES, the B channel is established in the circuit switching mode (process 154), and a pre-transmission procedure is performed to negotiate a transmission function with the partner terminal. (Process 156) The value obtained by adding 1 to the value of the transmission end page number information EPG of the file management table FMT selected at that time is set in the variable CPN for managing the page number to be transmitted (Process 15).
7).

Then, based on the content corresponding to the (CPN) page of the page map information MPG of the file management table FMT selected at that time, the image information of the (CPN) page is read from the image storage device 8 and the destination is read. Send to (Process 15
8). Also, at this time, each time one transmission unit is transmitted, it is monitored that the page ends or that a disconnection message DISC is received from ISDN (determination 15).
9,160 NO loops).

When the transmission of the image information for one page is completed and the result of determination 159 is YES, the value of the variable CPN at that time is the value of the page number information PGN of the file management table FMT selected at that time. It is checked whether or not the above has occurred (decision 161).

When the result of the determination 161 is NO, since there is a subsequent page, a procedure signal for notifying the end of the page to the partner terminal is sent (process 162), and the partner terminal responds to the signal of the page by the signal responded from the partner terminal. It is checked whether or not the message has been received normally (decision 163).

When the other terminal receives the data normally and the result of the decision 163 is YES, the value of the variable CPN and the value of the transmission end page number information EPG of the file management table FMT selected at that time are each increased by one. (Process 164), Process 158
Then, the image information of the next page is transmitted.

In addition, when the other party terminal cannot receive normally, the judgment 163
Is NO, the B channel is released to temporarily end the image information transmission (process 165), the call is restored (process 166), and a transmission error has occurred, and
The generated page number is displayed and output from the operation display unit 6 to notify the operator of that (step 167), and the call time information CTM of the file management table FMT selected at that time.
Is changed to 180 seconds (process 168), and this transmission process ends.

When all pages have been transmitted and the result of determination 161 is YES, the document has ended, so a procedure signal for notifying the end of the document is sent to the partner terminal (process 169), and the partner terminal responds. The signal checks whether the other terminal has received the last page normally (decision 170).

When the other terminal receives the data normally and the result of the determination 170 is YES, the content of the transmission result information RES of the file management table FMT selected at that time is set to “transmission OK” (processing 171), and B The channel is released (process 172), the call is restored (process 173), and this communication process ends.

If the result of the determination 170 is NO in a case where the other terminal has not been able to receive the data normally, the processing shifts to step 165.

Also, when the disconnection message DISC is received during the transmission of the image information and the result of the determination 160 is YES, the B channel is released (process 174), the call is restored (process 175), and the reception is performed. The cause is identified by checking the content of the reason display information element included in the disconnection message DISC (process 176), and the fact that image information cannot be transmitted and the cause content are displayed and output from the operation display unit 6 (process 177). ), The same calling time resetting process as described above (process 17), with the recurring call type content corresponding to the content of the reason display information element set as an argument
8: subroutine) to end the transmission process.

As described above, in the present embodiment, when a call is not established in the call setup procedure, or when a call is disconnected during data transmission, a call disconnection message received from ISDN to notify of these events. Based on the reason display information element included in the call, or the content of the call progress signal included in the call disconnection packet, whether or not recall is possible and the recall time interval are identified. A re-call operation can be performed according to the situation at the time of calling, and the efficiency of image information communication can be improved.

Further, in this embodiment, the image information is transmitted in page units, and a page whose transmission has not been completed is retransmitted at the time of recall.

By the way, in the embodiment described above, the present invention is referred to as Group 4
Although the present invention is applied to a facsimile apparatus, the present invention can be applied to other data terminal apparatuses.

In the above-described embodiment, the recall status is “OK”,
Classification into three types: "LONG OK" and "Unknown", and the recall time interval is set to 10 seconds, 60 seconds, and 180 seconds, respectively. The set value of the time interval can be appropriately set according to the terminal characteristics and the like.

In the above-described embodiment, the case where the ISDN has the packet control function has been described. However, since the ISDN does not have the packet control function, the present invention is similarly applied to the case where the access unit is used. can do.

[Effects of the Invention] As described above, according to the present invention, in a control method of a data terminal device using ISDN as a transmission path, when a call disconnection message is received during a call setup procedure or during data transmission, the call Based on the contents of the reason display information element included in the disconnection message, whether recall is possible and the recall interval time are determined, and the cause of the call disconnection is determined and visually displayed. A recall operation can be performed according to the situation of the network and the partner terminal,
As a result, there is an effect that useless calling operation is prevented.

Also, in the control method of a data terminal device for transmitting data in the packet switching mode, when a call disconnection packet is received during a call setup procedure or during data transmission, the content of the call progress signal included in the call disconnection packet is changed. Based on the determination of the possibility of re-calling and the re-call interval time, the cause of the call disconnection is determined and visually displayed, so that the re-call operation according to the situation of the data communication network and the partner terminal can be performed. As a result, there is an effect that useless calling operation is prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a group 4 facsimile apparatus according to one embodiment of the present invention, FIG. 2 is a schematic diagram showing an example of a file management table, and FIG. 3 (a) is an ISDN transmission procedure in a circuit switching mode. A time chart showing an example, FIG. 4 (b) is a time chart showing an example of a procedure when a called terminal rejects a call in the circuit switching mode, and FIG. 3 (c) is a case where an ISDN rejects a call in the circuit switching mode. FIG. 4 (a) is a time chart showing an example of a procedure for transmitting ISDN in the packet switching mode, and FIG. 4 (b) is a time chart showing an example of the procedure when the called terminal rejects a call in the packet switching mode. The time chart shown in the figure (c) is the IS in the packet switching mode.
Time chart showing an example of the procedure when the DN rejects the call,
5 (a) to 5 (d) are flowcharts showing an example of a calling operation, and FIG. 6 is a flowchart showing an example of a calling time resetting process. 1 ... system control unit, 2 ... system memory, 3 ... parameter memory.

Claims (3)

(57) [Claims] In a method for controlling a data terminal device using ISDN as a transmission path, when a call disconnection message is received during a call setup procedure or during data transmission, a reason indication information element included in the call disconnection message is provided. A method for controlling a data terminal device, comprising: determining whether or not a re-call can be made and a re-call interval time based on the contents of (i), and determining the cause of the call disconnection and visually displaying the result. 2. A method for controlling a data terminal device for transmitting data in a packet switching mode, comprising: receiving a call disconnection packet during a call setup procedure or during data transmission; a call progress signal included in the call disconnection packet. A method for controlling a data terminal device, comprising: determining whether or not a re-call can be made and a re-call interval time based on the contents of (i), and determining the cause of the call disconnection and visually displaying the result. 3. The data terminal apparatus according to claim 2, wherein if the content of the call progress signal is "network connection regulated", the recall interval time is set to a longer value. Control method.