JP2872731B2 - Communication terminal device and facsimile device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a telematic terminal such as a G4 facsimile,
Communication terminal devices (TE1, TE2, and T2 as defined in the CCITT recommendation), such as information processing devices and communication terminal adapters with ISDN communication functions.
Regarding A), in particular, it relates to recall processing when the incoming call is rejected.

[Prior Art] For example, as a conventional facsimile machine, a G3 facsimile (hereinafter, referred to as a G3 machine) that performs image communication via a public switched telephone network (PSTN) is known.
Has been widely used.

This is a device that modulates image data read by a reading device such as a scanner and sends it out to a line. Due to the frequency band limitation of analog signals, 9600 bps (bits per second)
Transmission speed was the practical limit. For this reason, it took the G3 machine several tens of seconds to send one A4 document.

However, recently, instead of the PSTN, an integrated services digital network (ISDN: Integrated Services Digital Network) capable of transmitting data as digital binary data without modulation has been provided.

Therefore, the International Telegraph and Telephone Advisory Committee (CCITT: Internatio
nal Telegraph and Telephone Consultative Commite
e) As a facsimile machine that can be connected to ISDN, G
Four facsimile machines (hereinafter referred to as G4 machines) were recommended.

This device can transmit one A4 document in a few seconds when connected to ISDN with a transmission speed of 64 Kbps. The G3 machine has a maximum document reading resolution of 8 x 7.7 dots / mm, which is 200 x 200 ppi (pels perinc
h). However, since the G4 can use a resolution of 400 × 400 ppi, it can realize higher definition image communication than the G3.

From the above, ISDN / G4 aircraft are expected to have great expectations in the field of image communication in the future.

FIG. 2 shows a signal sequence of G4 communication by the ISDN G4 machine.

In ISDN, outgoing / incoming calls, and near-side control such as disconnection,
This control is performed between the terminal and the network via a signal channel called a D channel, and this control is specified in CCITT Recommendation Q.931. Further, image communication control for a telematic terminal such as a facsimile is performed between terminals via an information channel called a B channel, and this control is specified in the CCITT Recommendation T series.

In FIG. 2, first, a calling terminal (left) transmits a G4 mode call setup (SETUP) message to the network via the D channel.

In the SETUP message, it is necessary to specify the information transfer capability of the B channel as a transfer capability information element. The information transfer capability can be selected from voice, 3.1KHz audio, unrestricted digital information, etc. In the case of G4 mode, the unrestricted digital information providing 64Kpbs end-to-end digital communication is selected.

On the other hand, upon receiving the SETUP message from the calling terminal, the network transmits a G4 mode SETUP message to the partner terminal (right) and accepts a call setup to the calling terminal (CALL PROC).
Send a message.

The called terminal receiving the SETUP message from the network responds to the network if it can accept the incoming call (CONN).
Send a message. Next, after transferring the received CONN message to the calling terminal, the network transmits a response acknowledgment (CONN ACK) message to the called terminal. The calling terminal that has received the CONN message from the network sends a CONN ACK to the network.
Send a message.

With the above procedure, one transmission path has been established between the calling terminal and the called terminal, and both terminals perform G4 image communication via the B channel. After the end of the image communication, the calling terminal transmits a disconnection (DISC) message to the network again via the D channel.

After transferring the received DISC message to the called terminal, the network transmits a release (REL) message to the calling terminal, and the calling terminal receiving this message completes the release to the network (REL COM). Send a message. Also, DIS from the network
The called terminal receiving the C message transmits a REL message to the network, and finally, the network transmits a REL COM message to the called terminal, thereby completing one communication.

The ISDN G4 machine can realize high-speed image communication by the above procedure. However, new models such as ISDN / G4 machines have a problem of interoperability with conventional models.

At present, about 3 million PS3 G3s are widely used in the OA field. ISDN is interconnected with the PSTN in order to maintain communication with existing terminals connected to the PSTN. Given the above background, G3 functions are indispensable for G4 aircraft.

However, since PSTN is an analog network, ISDN terminals and PSTN
Communication with TN terminals cannot use unrestricted digital information in G4 mode.

Therefore, a call from the G4 machine to the G3 machine using the unrestricted digital information in the G4 mode is rejected.

On the other hand, according to CCITT recommendation T.90, when an ISDN / G4 device with a G3 function communicates with a G3 device, 3.1KHz audio that provides communication in the 3.1KHz band is provided as the B-channel information transfer capability of the transmission capability information element. It is recommended to select and place the call as G3 mode.

Therefore, conventional G3 aircraft and G2 as in CCITT recommendation T.30
The technology of fallback that was performed in communication with the machine, G4
If applied to communication between G3 and G3 machines,
If the incoming call in the mode is rejected, it is possible that the call will be re-issued in the G3 mode. Hereinafter, this operation of the G4 machine is referred to as G3 fallback.

FIG. 3 shows a signal sequence of the G3 fallback operation by the ISDN G4 machine having the G3 function.

In FIG. 3, first, the calling terminal transmits a G4 mode SETUP message via the D channel, and the network that has received this message transmits a CALL PROC message to the calling terminal. Next, the network calls the other party's terminal, so the SE
The location of the partner terminal is checked based on the partner terminal number included in the TUP message. If it is found from this investigation that the called terminal is connected to the PSTN, G4 mode unrestricted digital information cannot be used.
Send a message. The calling terminal that has received the DISC message from the network sends a REL message to the network,
A REL COM message is returned from the network.

Next, the calling terminal gives up the G4 mode, and returns to the G3 mode SE.
Send a TUP message. In the case of the G3 mode, 3.1 kHz audio is selected as the information transfer capability of the transmission capability information element.

When the network receives the SETUP message from the calling terminal,
A ringing signal is transmitted to the called terminal connected to the STN, and a CALL PROC message is transmitted to the calling terminal.

If the called terminal can accept the incoming call, it sends a terminal response signal indicating off-hook to the network,
The network receives the terminal response signal and transmits a CONN message to the calling terminal. Then, the calling terminal that has received the CONN message from the network transmits a CONN ACK message to the network,
G3 image communication is performed with the called terminal via the B channel. After the end of the image communication, the calling terminal transmits a DISC message to the network again via the D channel. The network that has received this message transmits a disconnection signal indicating the end of the call to the called terminal, and then transmits a REL message to the calling terminal. Finally, the calling terminal transmits a REL COM message to the network, thereby completing the communication between the ISDN G4 and the PSTN G3.

[Problems to be Solved by the Invention] The basic interface of ISDN includes two B channels having a transmission speed of 64 Kbps and one D channel having a transmission speed of 16 Kbps.
Consisting of channels, commonly referred to as 2B + D. In order to take advantage of such features of ISDN, ISDN terminals are mainly equipped with simultaneous two communication functions.

However, it is clear that an ISDN / G4 machine with G3 function must have two G4 communication control programs and two G3 communication control programs in order to realize simultaneous two communication of any combination. This causes an increase in storage memory.

Therefore, currently available ISDN G4 machines are compatible with G4 communication.
There are many devices that have one control program for G3 communication and allow simultaneous communication only for G4 communication and G3 communication.

However, the G3 fallback of the prior art in the ISDN G4 machine has the following problem when the called terminal is an ISDN G4 machine capable of simultaneously executing the G4 communication and the G3 communication.

FIG. 4 is a signal sequence diagram in which an ISDN / G4 machine having a G3 fallback function makes a call to an ISDN / G4 machine that is already performing G4 communication with another terminal.

In FIG. 4, first, the calling terminal transmits a G4 mode SETUP message via the D channel, and the network that has received this message transmits a CALL PROC message to the calling terminal and transmits the CALL PROC message to the partner terminal. For G4 mode SETU
Send a P message.

The called terminal that has received the SETUP message compares the state of the own terminal and determines whether it is possible to accept a G4 mode incoming call. However, if G4 communication is currently in progress with another terminal, further G4 communication cannot be performed and DISC
Send a message.

The network transfers the received DISC message to the calling terminal. The calling terminal that has received the DISC message from the network
After transmitting the message and receiving the REL COM message, the G3 mode SETUP message is transmitted to the network by the G3 fallback operation described above.

The called terminal that has received the SETUP message checks the state of the own terminal, and is performing G4 communication with another terminal, but since G3 communication is possible, transmits a CONN message for accepting the incoming call to the network. The network transfers the received CONN message to the calling terminal.

The calling terminal that has received the CONN message performs G3 image communication with the called terminal via the B channel.

As described above, when an ISDN / G4 device according to the related art makes a call to an ISDN / G4 device that is performing G4 communication with another terminal,
A G3 fallback operation occurs and the called terminal performs G3 communication even though it has a G4 function.

That is, the G3 communication time is about 10 times the G communication time.
There is a problem that the communication fee increases about twice as much.

In addition, the above problem occurs not only in the G4 device but also in a communication terminal device that needs to communicate with a partner terminal connected to the PSTN.

In particular, in the case of the G4 machine, there is a problem that the document output to the called terminal by the G3 communication has a lower definition than the G4 communication.

Therefore, the present invention relates to a data communication (a communication using an information transfer capability of 3.1 kHz audio service) that immediately performs analog modulation of digital data for a communication terminal connected to ISDN. , Analog communication)
Telematics such as G4 facsimile that can perform communication with digital data as much as possible (meaning communication using a service with unrestricted information transfer capability, referred to as digital communication in this specification) without falling back to It is an object to provide a communication terminal such as a terminal or an information processing device having an ISDN communication function.

[Means for Solving the Problems] To achieve the above object, the present invention is a communication terminal device having a digital communication function and an analog communication function via ISDN, and when an incoming call is rejected, To switch between the communication function of the partner device predicting means for predicting the communication function of the partner device based on the received control information, and the re-calling means for re-calling using the communication function of the partner device predicted by the partner device predicting device. Holding means for holding the communication function switching condition of, the re-calling means, when the communication function switching condition held in the holding means is satisfied, regardless of the prediction result of the partner model prediction means, It is characterized by switching the communication function and calling again.

Further, the communication function switching condition held in the holding means is such that the incoming call is rejected even after repeating the predetermined number of re-calls by the communication function of the partner device predicted by the partner model prediction means. You may.

Further, the apparatus further comprises an immediate transmission property recognizing means for recognizing whether or not the information to be transmitted is information for which an immediate transmission is requested, and the communication function switching condition held in the holding means, when an incoming call is rejected, The case may be such that the immediate transmission recognizing means recognizes the information requesting immediate transmission.

A storage unit that stores information in a storage area; and a storage management unit that manages a use state of the storage area in the storage unit. The communication function switching condition held in the holding unit is such that an incoming call is rejected. In some cases, the free area of the storage unit managed by the storage management unit may be equal to or smaller than a predetermined capacity.

Further, the present invention provides, in order to achieve the above object, a G4 function unit for transmitting a G4 mode, a G3 function unit for transmitting a G3 mode, and, when an incoming call is rejected, a partner device based on received control information. Device prediction means for predicting a receivable communication mode, re-calling means for re-calling using the communication mode of the partner device predicted by the communication device prediction means, and a communication mode switching condition for switching the communication mode. Holding means for holding, when the communication mode switching condition held in the holding means is satisfied, regardless of the prediction result of the partner model prediction means, switches the communication mode Provided is a facsimile apparatus characterized by re-calling.

Further, the communication mode switching condition held in the holding means may be a case where the incoming call is rejected even if the re-calling is repeated a predetermined number of times according to the communication mode of the partner device predicted by the partner model predicting means.

Further, the apparatus further comprises an immediate transmission property recognizing means for recognizing whether or not the information to be transmitted is information requesting immediate transmission, and the communication mode switching condition held in the holding means, when an incoming call is rejected, The case may be such that the immediate transmission recognizing means recognizes the information requesting immediate transmission.

Further, a storage unit that stores information in the information area, and a storage management unit that manages the use state of the storage area of the storage unit, further comprising: a communication mode switching condition held in the holding unit, the incoming call rejection In some cases, the free area of the storage unit managed by the storage management unit may be equal to or smaller than a predetermined capacity.

Further, the communication mode switching condition held in the holding unit is a first mode in a case where an incoming call is rejected even after repeating a predetermined number of re-calls according to the communication mode of the partner device predicted by the partner model predicting unit. A condition, a second condition when the information to be transmitted when the incoming call is rejected is information requesting immediate transmission, and a storage area for storing the information when the incoming call is rejected has a predetermined capacity. At least one of the third conditions in the following case may be satisfied.

Further, in order to achieve the above object, the present invention predicts, in an ISDN communication terminal device, a communication function of a partner device based on reason display information of a received line disconnection procedure signal when an incoming call is rejected. There is also provided a fallback method characterized by re-calling using a communication function corresponding to the communication function of the device.

[Operation] According to the communication terminal device of the present invention, when an incoming call is rejected, the partner model predicting unit predicts the communication function of the partner device based on the reason display information of the received line disconnection procedure signal. Then, the re-calling means re-calls using a communication function corresponding to the communication function of the partner device predicted by the partner model prediction means.

As a result, when the communication terminal device having the digital communication function of the called side is already performing digital communication with another terminal, the call is re-established by the digital communication function without falling back to the analog communication, thereby increasing the communication fee. Can be prevented.

Further, according to the facsimile apparatus of the present invention, when the call control unit confirms the rejection of the incoming call of the other party device, the other party model prediction means receives the other party device from the reason display information of the received line disconnection procedure signal. The transmission mode that can be used. Then, the re-call instructing means transmits a call to the partner device in the transmission mode according to the prediction result of the partner model predicting unit,
Instructs the call control unit. The call control unit calls the partner device again in the designated transmission mode.

Thereby, the facsimile apparatus according to the present invention, the G4 machine having the G3 function of the called side, if already in G4 communication with another terminal, without causing a G3 fallback operation, since the re-call in the G4 mode, An increase in communication charges can be prevented, and high-definition image communication can be realized.

According to the fallback method of the present invention, the IS
In the DN communication terminal device, when an incoming call is rejected, the communication function of the partner device is predicted from the reason display information of the received line disconnection procedure signal, and a communication function corresponding to the predicted communication function of the partner device is used. By calling again, an unnecessary increase in communication charges is suppressed.

Embodiment An embodiment of the communication terminal device according to the present invention will be described below. Each embodiment described below will be described. In the communication terminal device according to each embodiment described below, the receiving side is the same as the conventional one, so that the description will be omitted and the transmitting side will be described. When the receiving function is not required, only the transmitting side described below may be provided.

First, a first example in which the communication terminal device according to the present invention is a G4 machine will be described as a first embodiment of the present invention.

FIG. 1 shows a system configuration of a G4 machine according to the first embodiment.

In the figure, 4 indicates an ISDN line. 1 is a main control unit that controls the entire apparatus, 2 is a partner model prediction unit that determines the type of the called terminal, 3 is an ISDN call control unit that executes ISDN / D channel call control procedures such as CCITT Recommendation Q.931, 5 is G4 of CCITT recommendation T.563 etc.
A G4 communication control unit for executing a communication procedure, 6 is a G3 communication control unit for executing a G3 communication procedure such as CCITT recommendation T.4, 7 is a MODEM for modulating and demodulating data, and 8 is a CCITT recommendation G.711. μ
A voice coding unit for performing digital-analog conversion in accordance with the law, 9 and 10 switches, 11 a scanner for reading and scanning a document, 12 a MH or MR coding method shown in CCITT recommendation T.4, CCITT Using the MMR encoding method shown in Recommendation T.6, an image conversion unit that compresses image data of a read document, 13 is an image memory that stores compressed image data,
Reference numeral 14 denotes a memory management unit that controls input / output of image data to / from the image memory 13. Reference numeral 15 denotes a document management table.

In FIG. 1, reference numeral 16 denotes a timer for measuring a unit time, and reference numeral 17 denotes an operation unit having a keyboard and a display.

 Next, the configuration of the document management table 15 is shown in FIG.

As shown in the figure, the document management table 15 includes, for one document, a communication mode indicating a mode in which the document is transmitted, a retry count indicating how many times a call can be repeated if an incoming call is rejected, A table is provided for a plurality of documents including a retry time indicating an interval from rejection to a recall, a storage start position indicating a storage area of a document stored in the image memory 13, and a storage end position.

Hereinafter, the operation of the G4 machine according to the first embodiment will be described.

First, a description will be given of a document reading process performed when a user sets a transmission document on the scanner 11 and designates the number of a called terminal by the operation unit 17.

 FIG. 6 shows the procedure of the document reading process.

First, the main control unit 1 waits until the user instructs the start of transmission by the operation unit 17 (step 601). Upon receiving the transmission start instruction, the main control unit 1 instructs the scanner 11 to start reading the set document, and the memory management unit
Instruct 14 to store the image data. Upon receiving the reading start instruction, the scanner reads and scans each line from the leading end of the set document and inputs the line to the image conversion unit 12 (step 60).
2).

The image conversion unit 12 compresses the input image data, and the memory management unit 14 converts the compressed image data into an image memory 13
(Step 603). When the above reading compression processing is repeated up to the trailing end of the document, the scanner 11 notifies the main control unit 1 of the reading end.

In step 604, upon receiving the read end notification, the main control unit 1 sets the communication mode of the document management table 15 to “G4”.
Is registered (step 605), and the allowable number of repetitions of recall when the incoming call is rejected is set as the number of retries (step 606).

Here, the allowable number of retries may be a fixed value of the apparatus or may be changeable by the user.

Next, the main control unit 1 sets 0 to the retry time of the document management table 15 (step 607), and stores the document storage position in the image memory 13 notified from the memory management unit 14 in the storage of the document management table 15. It is stored in the start position and the accumulation end position (step 608).

 Thus, the document reading and storing process is completed.

Next, a transmission process for calling and communicating with a partner terminal will be described.

 FIG. 7 shows the procedure of this transmission process.

 First, a normal G4 transmission will be described.

First, the main controller 1 refers to the document management table 15 and waits for the appearance of a transmission document having a retry time of 0 (step 701).

If the main control unit 1 finds a transmission document in which the retry time is 0, it refers to the communication mode of the document management table 15 and confirms that "G4" is set (step 702). ).

Next, the main controller 1 instructs the ISDN call controller 3 to make a G4 mode call (step 703).

The ISDN call controller 3 instructed to make the call sets unrestricted digital information as the information transfer capability of the transmission capability information element.
Send a SETUP message and wait for a response from the network. If the response from the network is a CONN message, the ISDN call control unit 3 transmits a CONN ACK message to the network and notifies the main control unit 1 of the call connection.

Further, in step 704, after receiving the call connection notification, the main control unit 1 connects the switch 9, and then sends the parameters such as the paper size and resolution used for communication to the G4 communication control unit 5 to receive the call. The main control unit 1 negotiates with the terminal (step 705). After the negotiation is completed, the main control unit 1 stores the image data in the image memory 13 stored in the document management table 15 from the storage start position to the storage end position in the memory management unit 14. , Via the G4 communication control unit 5 and the ISDN call control unit 3
It is transmitted to DN4 (step 706).

On the other hand, the memory management unit 14 monitors the image memory and notifies the main control unit 1 of the completion of transmission when all the image data in the specified image memory 13 has been transmitted.

In step 707, the main control unit 1 having received the transmission completion notification causes the G4 notification control unit 5 to execute communication end processing such as disconnection of the B channel (step 708).

Next, the main control unit 1 provides the ISDN call control unit 3 with a DISC and
A REL COM message is transmitted, and the call is disconnected (step 709). Finally, the main controller 1 clears the document management table 15 of the transmitted document (step 710), and ends the G4 transmission.

Next, recall processing when the G4 call is rejected will be described.

In step 703 of FIG. 7, the ISDN call control unit 3 instructed by the main control unit 1 to call the G4 mode transmits a SETUP message and waits for a response from the network.

The network checks the location of the partner terminal based on the number of the partner terminal included in the SETUP message, and when confirming that the terminal is connected to the PSTN, transmits a DISC message to the calling terminal. ISDN call control unit 3 which received DISC message
Communicates the call disconnection to the main control unit 1 and passes the information element included in the DISC message to the partner model prediction unit 2.

In steps 704 and 711 of FIG. 7, the main control unit 1
Upon receiving the notification of the reception of the DISC message from the ISDN call control unit 3, the called terminal model (G4 or G3
Machine) confirms the prediction result (step 712).

The partner model prediction unit 2 uses the DISC passed from the ISDN control unit 3
The model of the called terminal is predicted based on the information element of the message.

 Here, prediction of the model of the called terminal will be described.

 FIG. 8 shows the structure of the DISC message.

In FIG. 8, reference numeral 18 denotes an entire DISC message to be communicated, which includes an information element indicating a message type indicating that the message is a DISC and an information element indicating a reason for disconnection.

Furthermore, the reason indication has the structure shown in Figure 19, and an information element identifier indicating that this information element is a reason indication, a reason indication content length indicating the content length of the information element, and whether the information element is a CCITT standard. , Coding standards that represent non-CCITT standards, sources that represent networks with information elements, and
It has a reason indication value indicating the reason for disconnection.

Here, the generation source is "public network accommodating users (ISD
N) "and" relay network (for example, PSTN) ". In the reason display value, parameters such as "no route to the other party", "normal disconnection", "wearing user busy", and "no receiving user response" are set.

From the above reason display information element, the partner model prediction unit 2
For example, the model of the called terminal is predicted as follows.

(1) The reason indication value "No partner route" indicates that the requested unrestricted digital information transfer capability could not be obtained, that is, it is considered that the PSTN is being relayed.
Predicted to be TN / G3 aircraft.

(2) The reason display value "received user busy" or "no called user response" indicates that the called terminal is connected to the ISDN but did not accept the incoming call for some reason. Is predicted to be an ISDN G4 machine.

(3) The “relay network” of the generation source indicates that the called terminal is connected to another network, and is clearly not an ISDN G4 machine. Therefore, the called terminal is predicted to be a PSTN / G3 machine.

As described above, the partner model prediction unit 2 predicts the partner model based on the above conditions and notifies the main control unit 1 of the prediction.

Now, in Step 712 of FIG. 7, if the prediction result of the partner model prediction unit 2 is G3, the main control unit 1
Select "G" for the communication mode of the document
After registering "3" (step 713), the control unit 3 instructs the ISDN call control unit 3 to make a call in the G3 mode (step 716).

The ISDN call control unit 3 instructed to make the call sets the SE to 3.1 kHz audio as the information transfer capability of the transmission capability information element.
Send a TUP message and wait for a response from the network. Then, if the response from the network is a CONN message, the ISDN call control unit 3 transmits a CONN ACK message to the network and notifies the main control unit 1 of the continuation of the call.

In step 717, after receiving the call connection notification, the main control unit 1 connects the switch 10, and then sends the call to the G3 communication control unit 6.
Negotiate with the called terminal (step 718).

After the negotiation is completed, the main control unit 1 sends the image data in the image memory 13 to the memory management unit 14 to the ISDN 4 via the G3 communication control unit 6, the MODEM 7, the voice encoding unit 8, and the ISDN call control unit 3. Transmission is performed (step 719).

When all image data has been transmitted (step 720),
The main control unit 1 causes the G3 communication control unit 6 to execute communication end processing such as disconnection of the B channel (step 721).

Next, the main control unit 1 provides the ISDN call control unit 3 with a DISC and
A REL COM message is transmitted, and the call is disconnected (step 722). Finally, the main controller 1 clears the document management table 15 of the transmitted document (step 723), and ends the G3 fallback transmission.

However, in step 717, the response from the network is CONN
If the message is not a message but a DISC message (step 724), the main control unit 1 subtracts the number of retries in the document management table 15 of the document to be transmitted (step 72).
5) Further, a set value (for example, 60 seconds) in a retry time indicating a period until a recall is registered is registered (step 72).
6) Then, it is determined whether or not the number of retries is 0 (step 727). If it is 0, the user is informed of that (step 728), and a subsequent instruction is awaited.

If the number of retries is not 0, the transmission document in which the retry time is registered waits until the retry time becomes 0 by a timer process described below (step 701).

When the retry time becomes 0 in step 701, the main control unit 1 confirms that the communication mode of the document management table 15 is “G3” in this case (step 70).
2) Re-execute the G3 transmission process from step 716.

Here, the timer processing of the main control unit 1 will be described.

 FIG. 9 shows a procedure of a timer process of the main control unit 1.

The timer 16 measures time, and a unit time (for example, 1 second)
Is notified to the main control unit 1.

When the timer 16 notifies the elapse of the unit time (step 901), the main controller 1 refers to the document management table 15 and checks whether there is a transmission document (step 902).

If there is a transmission document, the main control unit 1
If the retry time for 15 has not reached 0 (step
903), the unit time is subtracted from the value of the retry time (step 904), and the process proceeds to the next transmission document (step 90).
2). When the above processing is completed for all the transmission documents in the image memory 13, the next notification of the elapse of the unit time from the timer 16 is waited.

Next, a description will be given of a call to an ISDN / G4 machine during G4 communication with another terminal, which is a problem of the prior art example.

In FIG. 7, after instructing the ISDN call controller 3 to transmit a G4 mode SETUP message to the ISDN call controller 3 (step 703), the main controller waits until the ISDN call controller 3 receives a response message from the network (step 703). Steps 704, 711).

The called terminal that has received the SETUP message checks the status of its own device, and transmits a DISC message for rejecting the incoming call to the network because G4 communication is being performed with the current location terminal. At this time, for example, “Destination user busy” is set as the reason display information element of the DISC message.

This DISC message is transferred to the calling terminal via the network. The ISDN call control unit 3 of the calling terminal notifies the main control unit 1 of the reception of the DISC message, and passes the reason display information element to the partner model prediction unit 2. The partner model predicting unit 2 predicts the partner model as an ISDN / G4 machine by referring to the passed reason display information element and determining that the destination model is “receiving user busy”,
The main control unit 1 is notified.

The main control unit 1 confirms the reception of the DISC message in step 711, and further confirms in step 712 that the partner model is G4 based on the prediction result of the partner model prediction unit 2.

Next, the main controller 1 subtracts the number of retries in the document management table 15 of the document to be transmitted (step 714), registers a set value (for example, 60 seconds) in the retry time (step 715), and thereafter It is determined whether the number of retries is 0 (step 727). If it is 0, the user is informed of that (step 728), and a subsequent instruction is awaited.

If the number of retries is not 0, the transmission document registered with the retry time waits until the retry time becomes 0 (step 701). At this time, the communication mode of the document management table 15 is not changed to “G3”, but remains “G4”.

The retry time registered in the document management table 15 is decremented for each unit time by the timer processing shown in FIG. Then, the main control unit 1 confirms that the communication mode of the document management table 15 is “G5” (step 702), and executes the G4 transmission processing after step 703 on the transmission document in which the retry time becomes zero. Re-execute.

As described above, the ISDN / G4 machine of the present invention is capable of recalling in the G4 mode without G3 fallback even while the called ISDN / G4 machine performs G4 communication with another terminal. .

Hereinafter, a second example in which the communication terminal device according to the present invention is a G4 machine will be described as a second embodiment of the present invention.

The configuration of the G4 according to the second embodiment is the same as that of the G4 according to the first embodiment, and a description thereof will be omitted.

 Hereinafter, the operation will be described.

FIG. 10 shows a transmission processing procedure for calling and communicating with the partner terminal.

In the figure, the same steps as those in FIG. 7 showing the transmission processing according to the first embodiment described above are denoted by the same reference numerals.

The ISDN / G4 machine according to the first embodiment sets the called terminal to G4
If it is predicted, the G3 call will not be made.

However, if the called terminal is performing G4 communication with another terminal for a long time, transmission cannot be performed during that time. For example, if the transmitted document requires immediate characteristics, the discomfort of the user increases. Sometimes.

In addition, if a plurality of other transmission documents are accumulated while repeating the G4 call, the image memory 13 may have no free area. If there is no free space in the image memory 13, not only the subsequent transmission reservation cannot be made, but also the reception from other terminals cannot be accepted, so that the efficiency is deteriorated.

Therefore, in the G4 machine according to the second embodiment, as shown in Step 1001 in FIG.
If the call is still rejected after repeating the set number of retries (step 606 in FIG. 6), a constant value is set again to the number of retries (step 1002).
Control is performed to shift to G3 fallback transmission processing after 716.

The operation unit 17 is provided with an immediate transmission instruction key to be pressed when the user desires immediate transmission.
If the incoming call in the mode is rejected, and if the immediate transmission instruction key has been pressed (step 1003), step 71
Control is performed to proceed to G3 fallback transmission processing after 6.

Further, the memory management unit 14 includes means for monitoring the use status of the image memory 13 and notifying the main control unit 1 of the free space,
If the incoming call in the G4 mode is rejected, the main control unit 1 notifies the memory management unit 14 that there is no free area, that is, the memory is full (step 1004).
The processing shifts to G3 fallback transmission processing after 6.

Note that among the three steps for determining the transition to the G3 fallback transmission process (steps 1001, 1003, and 1004),
Of course, one or two steps may be provided.

The processing of each step other than the three steps for determining the transition to the G3 fallback transmission processing (steps 1001, 1003, and 1004) is the same as the step of the same number in the first embodiment (see FIG. 7). The description is omitted.

Next, an example in which the communication terminal device according to the present invention is an information processing device such as a personal computer or a large-scale computer will be described as a third embodiment of the present invention.

Conventionally, an information processing device converts digital data into analog data and communicates via the PSTN. In this case, the communication system includes a personal computer recommended communication system notified by the Ministry of Posts and Telecommunications.

Later, with the realization of ISDN, information processing devices connected to ISDN became capable of digital communication.

However, the information processing devices connected to these ISDN
To maintain compatibility with conventional information processing devices, ISDN
It is necessary to provide an analog communication function by PSTN in addition to the digital communication function by, but in this case, a fallback function from digital communication to analog communication is required.

However, since the information processing apparatus is performing digital communication with another apparatus, it is not advisable to switch subsequent calls to analog communication when the incoming call is rejected while digital communication is possible.

This is because the communication time increases and the communication fee increases.

Therefore, the information processing apparatus according to the third embodiment includes a partner model predicting unit, similarly to the G4 machine according to the first embodiment.
Then, the partner model is predicted, and a retry is performed according to the result.

The configuration of the information processing apparatus according to the present embodiment is such that the scanner 11, the image conversion unit 12, and the image memory 13, which are the facsimile function units in the G4 machine described in the first embodiment, are replaced with the information processing function unit. It is.

 Hereinafter, the operation of the information processing apparatus will be described.

When the digital communication is rejected, the partner model prediction unit determines the communication function of the called party from the reason display information element of the DISC message as follows, for example.

(1) The reason indication value "No partner route" indicates that the requested unrestricted digital information transfer capability was not obtained, that is, it is considered that the PSTN is being relayed. Predict not to have digital communication function.

(2) The reason display value “received user busy” or “no called user response” indicates that the called information processing apparatus is connected to the ISDN, but did not accept the called for some reason. It is predicted that the called information processing device has a digital communication function based on ISDN.

(3) The "relay network" of the generation source indicates that the called terminal is connected to another network, and the called information processing device is an ISDN.
It does not have a digital communication function.

Then, based on the prediction, the transmission processing is performed in the same manner as in the first embodiment or the second embodiment. In this case, G4 communication referred to in the first and second embodiments corresponds to digital communication, and G3 communication corresponds to analog communication.

As described above, the information processing apparatus according to the present embodiment retries digital processing without falling back to analog communication for an information processing apparatus that is performing digital communication with another apparatus. Therefore, an unnecessary increase in communication fee can be prevented.

As described above, according to the communication terminal apparatus according to the present embodiment, even when the called communication terminal apparatus is performing digital communication with another terminal, the communication terminal apparatus does not fall back to analog communication and recurs later in digital communication. Since the call is made, the required communication time is about one-tenth of that in the case of the fallback transmission of the analog communication, and the line usage fee can be greatly reduced. Furthermore, when the communication terminal device is a G4 machine, the called user can obtain a document that is approximately four times as accurate as when receiving in the G3 mode.

Also, only in the case where transmission is impossible even if the digital communication is tried many times, or in the case of transmission of a document requiring immediacy, or when memory is full, etc., fallback transmission by analog communication is attempted regardless of the partner model. By that
Efficiency improvement can be expected.

[Effects of the Invention] As described above, according to the present invention, a communication terminal device capable of performing digital communication as much as possible without immediately falling back to a communication terminal connected to ISDN is provided. be able to.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of an ISDN G4 machine according to a first embodiment of the present invention, FIG. 2 is a communication sequence diagram showing a communication procedure with the ISDN G4 machine, and FIG. 3 is a PSTN G3. Sequence diagram showing the communication procedure with the device, FIG. 4 shows the G4
FIG. 5 is a communication sequence diagram showing a communication procedure with a communicating ISDN / G4 machine, FIG. 5 is an explanatory diagram showing a configuration of a document management table 15,
FIG. 6 is a flowchart showing a procedure for reading and accumulating a transmission document, FIG. 7 is a flowchart showing a procedure for transmission processing, FIG. 8 is an explanatory diagram showing a DISC message configuration, and FIG. 9 shows a procedure for timer processing. FIG. 10 is a flowchart showing a procedure of transmission processing of the ISDN / G4 apparatus according to the second embodiment of the present invention. 1 ... main control unit, 2 ... partner model prediction unit, 3 ... ISDN call control unit, 5 ... G4 communication control unit, 6 ... G3 communication control unit, 11
…… Scanner, 12… Image conversion unit, 13… Image memory,
14: Memory management unit, 15: Document management table, 16:
Timer, 17 ... Operation unit.

Continuation of front page (56) References JP-A-2-174347 (JP, A)

Claims (9)

(57) [Claims] 1. A communication terminal device having a digital communication function and an analog communication function via ISDN, and, when an incoming call is rejected, a communication terminal which predicts a communication function of the other device based on received control information. Using a communication function of the partner device predicted by the partner model prediction unit, a recalling unit that makes a call again, and a holding unit that holds a communication function switching condition for switching a communication function, A communication terminal for switching a communication function and re-calling, regardless of a prediction result of the partner model prediction unit, when a communication function switching condition held in the holding unit is satisfied; apparatus. 2. The communication terminal device according to claim 1, wherein the communication function switching condition held in the holding unit is a predetermined number of times of repetition by the communication function of the partner device predicted by the partner model prediction unit. A communication terminal device wherein a call is rejected even if a call is repeated. 3. The communication terminal device according to claim 1, further comprising: an immediate transmission property recognizing means for recognizing whether or not the information to be transmitted is information requesting immediate transmission. A communication terminal device according to claim 1, wherein said communication function switching condition is such that when the incoming call is rejected, said immediate transmission property recognizing means recognizes that the information is a request for immediate transmission. 4. The communication terminal device according to claim 1, further comprising: a storage unit configured to store information in a storage area; and a storage management unit configured to manage a use state of the storage area of the storage unit. The communication function switching condition held in the holding unit is characterized in that, when an incoming call is rejected, the free area of the storage unit managed by the storage management unit is equal to or less than a predetermined capacity. Communication terminal device. 5. A G4 function unit for transmitting in G4 mode, a G3 function unit for transmitting in G3 mode, and when a call is rejected, a communication mode receivable by a partner device is predicted from received control information. And a holding unit for holding a communication mode switching condition for switching the communication mode by using the communication mode of the partner device predicted by the partner model prediction unit. When the communication mode switching condition held in the holding unit is satisfied, the recalling unit switches the communication mode and re-calls regardless of the prediction result of the partner model prediction unit. Facsimile machine. 6. The facsimile apparatus according to claim 5, wherein the communication mode switching condition held in said holding means is a predetermined number of re-calls according to the communication mode of the other apparatus predicted by said other model predicting means. The facsimile apparatus is characterized in that the incoming call is rejected even if the above is repeated. 7. The facsimile apparatus according to claim 5, further comprising an immediate transmission recognizing means for recognizing whether or not the information to be transmitted is information for which an immediate transmission is requested, and holding the information in the holding means. The facsimile apparatus is characterized in that the communication mode switching condition is a case where, when the incoming call is rejected, the immediate transmission recognizing means recognizes that the information is a request for immediate transmission. 8. The facsimile apparatus according to claim 5, further comprising: a storage unit that stores information in a storage area; and a storage management unit that manages a use state of the storage area of the storage unit. The communication mode switching condition held by the means is that, when an incoming call is rejected, the free area of the storage unit managed by the storage management unit is equal to or smaller than a predetermined capacity. apparatus. 9. The facsimile apparatus according to claim 5, wherein the communication function switching condition held in said holding means is a predetermined number of re-calls according to the communication mode of the other apparatus predicted by said other model predicting means. The first condition when the incoming call is rejected even after repeating the above, the second condition when the information to be transmitted is information requesting immediate transmission when the incoming call is rejected, Wherein at least one of a third condition when a storage area for storing information is equal to or less than a predetermined capacity is satisfied.