JP3135621B2 - ISDN facsimile machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ISDN facsimile apparatus having a group 3 facsimile function and a group 4 facsimile function and using ISDN as a transmission line.

[0002]

2. Description of the Related Art ISDN using ISDN as a transmission line
The facsimile apparatus has a function of the CCITT Recommendation T.30. There is a Group 4 facsimile machine specified in 5. Since the group 4 facsimile apparatus has a function higher than that of the group 3 facsimile apparatus used for the public telephone line network and has a higher data transmission speed, the group 4 facsimile apparatus is generally used as a group 3 facsimile apparatus. The communication cost is lower than the device.

Further, ISDN has an inter-network connection function with a public telephone line network, and the public telephone line network uses a very large number of group 3 facsimile apparatuses connected thereto. The facsimile machine needs to transmit image information to and from a group 3 facsimile machine connected to the public telephone line network.

[0004] Further, an ISDN facsimile apparatus having only a group 3 facsimile function as an apparatus function has been put into practical use so that image information transmission using ISDN can be performed at low cost.

As described above, in practice, an ISDN facsimile apparatus needs to be capable of transmitting image information to both a group 4 facsimile apparatus and a group 3 facsimile apparatus. Therefore, generally, an ISDN facsimile apparatus It often has not only the function of the group 4 facsimile apparatus but also the function of the group 3 facsimile apparatus.

As described above, since the communication partner of the ISDN facsimile apparatus is a group 4 facsimile apparatus or a group 3 facsimile apparatus, it is necessary to confirm the function of the terminal of the other party before starting communication.

[0007] There are the following three methods for checking the device function of the partner terminal.

1) Inquiring of the user of the partner terminal,
Know the device function of the partner terminal.

2) When a call is made on the assumption that the other party terminal is a group 4 facsimile machine, and the call setting operation at that time fails for a reason other than the busy state of the other party terminal, the function of the other party terminal becomes the group 3 The other terminal is determined to be a facsimile machine, and the terminal is called again as a group 3 facsimile machine.

[0010] 3) Assuming that the other terminal is a group 4 facsimile machine, and making a call, if the call can be set at that time, it is determined that the device function of the other terminal is a group 4 facsimile machine.

[0011]

However, such a conventional method has the following disadvantages.

That is, in the first method, the operation of confirming with the user of the partner terminal is troublesome, and in the second and third methods, the device function of the partner terminal must be performed unless at least one call setting operation is performed. There is a disadvantage that it is impossible to know and a useless call setting operation is performed.

The present invention has been made in view of such circumstances, and has as its object to provide an ISDN facsimile apparatus that can appropriately perform a call setting operation in accordance with the terminal function of a partner terminal.

[0014]

According to the present invention, when a call is originated, a first group 4 facsimile function is set as a device function.
And a second call setting message in which a group 3 facsimile function is set as a device function.
The first call setup message is sent sequentially to the DN, and when a call setup message having a possibility of call connection is received in response to the first call setup message, the call setup operation related to the second call setup message is terminated and the first call setup message is terminated. Performs the call setup procedure operation according to the call setup message, does not receive a call setup message having a possibility of call connection in response to the first call setup message, and receives the second call setup message in response to the second call setup message. On the other hand, when a call setting message having a possibility of call connection is received, transmission control means for terminating the call setting operation according to the first call setting message and performing a call setting procedure operation according to the second call setting message. It is provided with.

[0015]

Therefore, when the partner terminal has the group 4 facsimile apparatus function, image information transmission using the group 4 facsimile apparatus function with low communication cost and good image information quality is performed. Therefore, the image information transmission efficiency is significantly improved. Further, when it is determined that the other terminal has only the group 3 facsimile apparatus function, the image information transmission using the group 3 facsimile apparatus function is performed. Transmission can take place.

[0016]

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

FIG. 1 shows an ISD according to an embodiment of the present invention.
1 shows an N facsimile machine. Note that this ISDN
The facsimile apparatus uses ISDN as a transmission path and has two device functions, a group 3 facsimile function and a group 4 facsimile function.

In FIG. 1, the control unit 1 controls the ISDN
The system memory 2 stores a processing program to be executed by the control unit 1 and various data necessary to execute the processing program, and a work area of the control unit 1. It constitutes.

The parameter memory 3 stores various kinds of information unique to the facsimile machine.
It is composed of a rewritable nonvolatile semiconductor storage device such as a battery-backed SRAM (static random access memory).

The scanner 4 is for reading an original image at the resolution set in the group 4 facsimile apparatus, and the plotter 5 is for recording and outputting the image at the resolution set in the group 4 facsimile apparatus. is there.

The operation display unit 6 is used to operate the facsimile machine, and includes various operation keys and
It comprises various display devices such as a liquid crystal display for displaying guidance information and the like to the operator.

The encoding / decoding section 7 encodes and compresses an image signal by a predetermined encoding method, and decodes the encoded and compressed image information into an original image signal. The pixel density converter 8 includes a scanner 4 and a plotter 5
When the pixel density of the image is different from the pixel density of the image that can be transmitted by the terminal device of the other party, the pixel density is mutually converted.

The image storage device 9 is for storing various information such as a transmission image signal, transmission image information, reception image information and a reception image signal.

The ISDN interface circuit 10 includes an ISDN
A layer 1 signal control unit 11 is provided for physically connecting to a DN and a signal processing function of the ISDN layer 1 and a signal of a D channel (signal channel) and a signal of two B channels (information channels). It has an integration / separation function.

The D-channel transmission control section 12 is for performing transmission control processing such as call control processing performed with the ISDN using the D channel. The group 3 facsimile communication control section 13 uses the B channel of the ISDN. To perform group 3 facsimile communication operation,
The group 4 facsimile communication control unit 14 performs a group 4 communication operation using ISDN B.

Control unit 1, system memory 2, parameter memory 3, scanner 4, plotter 5, operation display unit 6, encoding / decoding unit 7, pixel density conversion unit 8, image storage unit 9, D-channel transmission control unit The group 12, group 3 facsimile communication control unit 13, and group 4 facsimile communication control unit 14 are connected to an internal bus 15, and exchange of various information between these elements is mainly performed through the internal bus 15. Done.

In this ISDN terminal device, a call is made to a partner terminal in a state where an image of a transmission original is once read and stored, and in order to manage each image information transmission, FIG. It forms management information as shown.

The management information includes job number information for identifying each management information, transmission designated time information for storing the time at which the image information is transmitted, and IS of the partner terminal.
To store the other party's ISDN number information for storing the DN number, transmission result information for storing the image information transmission result, call number information for storing the number of calls, and a transmission mode specified by the user. , File number information for storing transmission image information stored in the image storage device 9, and page number information indicating the number of pages of the transmission image information.

The transmission result information includes group 4
Group 4 / group 3 mode standby mode in which the call setting operation of the facsimile apparatus function and group 3 facsimile apparatus function are continuously performed during the same calling operation, group 4 standby mode in which the call setting operation of the group 4 facsimile apparatus function is performed, group One of the group 3 standby mode for performing the call setting operation of the 3-facsimile apparatus function, OK indicating that the transmission operation has been normally completed, and NG indicating that the transmission operation has not been normally completed is set. The group 4 / group 3 standby mode is set as the initial value.

FIG. 3A shows an example of a call control procedure in a circuit switching mode performed by a terminal device connected to the ISDN with the ISDN.

That is, the originating terminal first sets the circuit switching mode as the transfer mode, sends a call setup message SETUP designating the destination terminal as the destination to the ISDN, requests a call setup with the destination terminal, and requests the ISDN Sends a call setup message SETUP to the designated destination terminal to make a call. Further, the ISDN sends a call setting acceptance message CALL_PROC for notifying the call setting status to the calling terminal.

Upon detecting an incoming call, the called terminal sends out a call message ALERT to the ISDN at predetermined intervals continuously when the own terminal is ready to receive a call.
N sends a call message ALERT to the calling terminal to notify that calling of the called terminal has started.

Upon receiving the incoming call, the called terminal sends a response message CONN to the ISDN, and the ISDN sends a response message CONN to the calling terminal to notify that the called terminal has accepted the call.

The ISDN sends a response confirmation message CONN_ACK to the destination terminal to confirm the response of the destination terminal, and at that time, an information channel (B channel) for data transmission between the calling terminal and the destination terminal. Is established.

Thus, data transmission using the information channel is performed between the originating terminal and the destination terminal according to the transmission control procedure set for the transmission 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.
The SC is transmitted to the destination terminal to notify the recovery 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 release of the channel is completed, the calling terminal sends a release completion message REL_COMP to the ISDN to notify that fact, and accordingly, the ISDN sends a release completion message REL_COMP to the destination terminal, and the release of the information channel is established. Then, the information channel set between the calling terminal and the called terminal is completely released.

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

When the called terminal cannot answer the incoming call, as shown in FIG. 2B, when the called terminal receives the call setup message SETUP from the ISDN, the called end message REL_COMP containing the reason why the incoming call cannot be answered is received.
To the ISDN.

As a result, 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 transmits the release completion message RE
In response to L_COMP, release the call.

When the terminating terminal does not perform the incoming call response operation, the ISDN responds to the calling terminal with a release completion message REL_COMP based on no response from the partner terminal, and releases the call.

As shown in FIG. 4A, each message for ISDN call setting is a protocol specification (format, format,
Protocol identifier)
A call number to identify which call the message is involved in, a message type to identify the content of each message, mandatory information elements that are always added to each message, and each message And additional information elements that are added as needed. Note that 0, 1, or a plurality of essential information elements are set according to the message type, and 0, 1, or a plurality of additional information elements are arranged according to the situation.

The call setup message SETUP has "communication capability" as an essential information element, as shown in FIG.
The additional information elements include, for example, "calling number",
It has information elements such as "destination number", "lower layer compatibility", "higher layer compatibility", and "user / user".

The release completion message REL_COM
As shown in FIG. 3C, P has, for example, "reason display" as an essential information element, and information such as "display" and "user / user" as additional information elements. Has elements.

The outline of these information elements will be described.

The “transmission capability” information element indicates whether the content of information to be transmitted is voice, unrestricted digital information, restricted digital information, 3.1 kHz audio, 7 kHz audio, or video. Capability, transfer mode indicating whether the switching function used is circuit switching or packet switching, information transfer speed indicating information transfer speed, information indicating information transfer mode, information indicating user information protocol, etc. Consists of

The “calling number” information element is the ISDN of the calling terminal.
And the "destination number" information element is the IS of the destination terminal.
Represents the DN number.

The "lower layer compatibility" information element is used for checking the possibility of communication with the partner terminal, and has the same basic contents as the "transmission capability" information element. Further, the "lower layer consistency" information element includes more detailed contents.

The "higher layer compatibility" information element is used for checking the compatibility with the partner terminal. For example, group 2 / group 3 facsimile, group 4
Displays which terminal function is provided among terminal functions such as facsimile, mixed mode, teletex, videotex, telex, and a message handling system.

The "user / user" information element is used for transmitting information between users, and the content of the "user / user" information element is transmitted transparently without being interpreted by ISDN. It is transmitted to the other user.

The “reason indication” information element is a message containing the information element (in this case, the release completion message REL_
(COMP) is generated, and diagnostic information indicating the reason for the error that occurred during the call setup procedure and the like is notified.

The "display" information element is used to indicate various display information from the ISDN to the user.

The calling operation performed by the ISDN facsimile apparatus having the above configuration will be described according to the type of the terminal device connected to the destination (ISDN number) and the idle state. In the following description, a terminal TA represents the ISDN facsimile apparatus of FIG. 1, a terminal TB represents an ISDN facsimile apparatus having only a group 4 facsimile apparatus function, and a terminal T
C is an I with only group 3 facsimile machine function
Represents an SDN facsimile machine.

In the case where only the terminal TB is connected to the other party and the terminal TB is in an empty state, FIG.
The operation shown in FIG. In the following description, the value of the call number is shown in parentheses for each message.

That is, first, the terminal TA sets the call number a,
Call setting message SETUP of device function G4 (hereinafter referred to as call setting message SETUP (a, G4))
, Call number b, call setting message SET of device function G3
UP (hereinafter, call setup message SETUP (b, G3)
) Are sequentially transmitted to the ISDN.

Thus, from the ISDN to the destination,
The call setup message SETUP (c, G4) and the call setup message SETUP (d, G3) are sequentially transmitted, and the call setup acceptance message CALL_PROC (a) and the call setup acceptance message CALL_PROC (b) are sent from the ISDN to the terminal TA. Are sequentially answered.

At this time, since the terminal TB is idle, the terminal TB sends a response message CONN (c) to the incoming call response to the call setup message (c, G4).
Send to DN. As a result, the response confirmation message CONN_ACK (c) is returned from the ISDN to the terminal TB, and the response message CONN (a) is transmitted from the ISDN to the terminal TA.

Therefore, the terminal TA determines that the image information can be transmitted by the group 4 facsimile function with the other terminal, and terminates the call setting operation according to the call setting message SETUP (b). DIS
C (b) is sent to ISDN to perform a call recovery procedure.

Then, the terminal TA activates the group 4 facsimile communication control unit 14, executes the group 4 facsimile transmission procedure using the B channel established with the terminal TB at that time, and transmits the transmission image information to the terminal TA. Send to TB. When the image information transmission operation of the B channel is completed, a call recovery procedure is executed to release the call.

When only the terminal TB is connected to the other party and the terminal TB is busy, the operation shown in FIG.

In this case, the terminal TB, in response to the received call setup message SETUP (c, G4), sets the information indicating that the disconnect reason is “busy” in the “reason display” information element, and completes the release. Message REL_COM
Send P (c) to ISDN.

As a result, the ISDN sends a release completion message REL_COMP (a) to the terminal TA to release the call.

At this time, since the group 3 facsimile machine is not connected to the destination, the destination does not reply to the ISDN with a call setting message relating to the call number d. As a result, the ISDN notifies the terminal TA that the predetermined reason has passed since the call setup message SETUP (d, G3) has been sent to the terminal TA, and indicates the reason for disconnection in the “reason display” information element to be “No response from the other terminal”. Release completion message R in which information indicating that
Send EL_COMP (b).

As a result, the terminal TA determines that the group 4 facsimile apparatus is connected to the other party and that the group 4 facsimile apparatus is busy, shifts to the group 4 standby mode, and Perform call operation.

In this case, when receiving the release completion message REL_COMP (a) from the ISDN, the terminal TA can know that the group 4 facsimile apparatus is connected to the destination, and immediately thereafter, The call recovery procedure for the call number b may be started.

When only the terminal TC is connected to the other party and the terminal TB is idle, an operation as shown in FIG. 6A is performed.

That is, first, the terminal TA transmits a call setup message SETUP (a, G4) and a call setup message S
ETUP (b, G3) is sequentially transmitted to ISDN.

Thus, from the ISDN to the destination,
The call setup message SETUP (c, G4) and the call setup message SETUP (d, G3) are sequentially transmitted, and the call setup acceptance message CALL_PROC (a) and the call setup acceptance message CALL_PROC (b) are sent from the ISDN to the terminal TA. Are sequentially answered.

At this time, since the terminal TC is in an idle state, the terminal TC sends a response message CONN (d) to the incoming call response to the call setup message (d, G3).
Send to DN. As a result, the response confirmation message CONN_ACK (d) is transmitted from the ISDN to the terminal TC, and the response message CONN (b) is transmitted from the ISDN to the terminal TA.

Here, since there is a possibility that the group 4 facsimile apparatus is connected to the destination, the terminal TA waits until a call setting message relating to the call number a is received from the ISDN.

On the other hand, at this time, since the group 4 facsimile machine is not connected to the destination, the destination does not respond to the ISDN with a call setting message for call number c. As a result, the ISDN notifies the terminal TA that the predetermined reason has passed since the call setup message SETUP (c, G4) has been sent to the terminal TA, and the reason for disconnection is indicated in the “reason display” information element as “no response from the partner terminal”. Release completion message R in which information indicating that
Send EL_COMP (a).

As a result, at this time, the terminal TA
It is determined that image information can be transmitted by the group 3 facsimile function and the image information cannot be transmitted by the group 4 facsimile function, and the group 3 facsimile communication control unit 13 is activated. A group 3 facsimile transmission procedure is executed by using the B channel established between the terminal and the terminal TC. Then, when the image information transmission operation of the B channel is completed, a call recovery procedure is executed to release the call.

When only the terminal TC is connected to the other party and the terminal TC is busy, the operation shown in FIG.

In this case, in response to the received call setup message SETUP (d, G3), terminal TC sets release completion information in which the information indicating that the disconnect reason is “busy” is set in the “reason display” information element. Message REL_COM
Send P (d) to ISDN.

As a result, the ISDN sends a release completion message REL_COMP (b) to the terminal TA to release the call.

At this time, since the group 4 facsimile machine is not connected to the destination, the ISDN sends the call setup message SETUP in the same manner as described above.
At the point in time when a predetermined time has elapsed after sending (c, G4), the terminal TA is set with information indicating that the disconnect reason is “no response from the partner terminal” in the “reason display” information element. Completion message REL_COMP (a)
Is sent.

As a result, the terminal TA has only the group 3 facsimile apparatus connected to the destination, and
It is determined that the group 3 facsimile apparatus is busy, the mode is shifted to the group 3 standby mode, and the recall operation is performed.

When the terminal TB and the terminal TC are connected to the other party, and the terminal TB and the terminal TC are in the idle state, the operation shown in FIG. 7A is performed.

That is, first, the terminal TA transmits the call setup message SETUP (a, G4) and the call setup message S
ETUP (b, G3) is sequentially transmitted to ISDN.

Thus, from the ISDN to the destination,
The call setup message SETUP (c, G4) and the call setup message SETUP (d, G3) are sequentially transmitted, and the call setup acceptance message CALL_PROC (a) and the call setup acceptance message CALL_PROC (b) are sent from the ISDN to the terminal TA. Are sequentially answered.

At this time, since terminal TB and terminal TC are each in an idle state, terminal TB responds to the call setup message (c, G4) by receiving a response message C.
ONN (c) is sent to ISDN, and terminal TC
Sends a response message CONN (d) to the ISDN to answer the call setup message (d, G3). As a result, the terminal TB and the terminal TC
Includes a response confirmation message CONN_ACK
(C) and the response confirmation message CONN_ACK
(D) is responded, and the terminal from the ISDN to the terminal TA:
Response message CONN (a) and response message C
ONN (b) are sequentially transmitted.

As a result, at this time, the terminal TA
It is determined that image information transmission is possible with the other party's destination and either the group 4 facsimile function or the group 3 facsimile function. In this case, it is determined that image information transmission using the group 4 facsimile function is performed.

Therefore, terminal TA sends a disconnection message DISC (b) to ISDN in order to end the call setting operation with the group 3 facsimile apparatus, and performs a call recovery procedure with terminal TC. .

At the same time, the terminal TA activates the group 4 facsimile communication control unit 14, and at that time, the terminal T
A group 4 facsimile transmission procedure is executed using the B channel established with B, and the transmission image information is transmitted to the terminal TB. Then, when the image information transmission operation of the B channel is completed, a call recovery procedure is executed to release the call.

Further, the terminal TB and the terminal TC
Is connected and the terminal TC is busy, an operation as shown in FIG.

In this case, the terminal TB sends a response message CO to answer the call setup message (c, G4).
NN (c) is sent to ISDN and the terminal TC
Is the received call setup message SETUP (d, G3)
, The reason for disconnection is "busy" in the "reason display" information element
Is transmitted to the ISDN. The release completion message REL_COMP (d) in which information indicating that

Thus, from the ISDN to the terminal TB,
The response confirmation message CONN_ACK (c) is responded, and the response message CONN (a) is sent from the ISDN to the terminal TA. At the same time, ISDN
Is a release completion message REL_CO to the terminal TA.
Send MP (b) to release the call related to call number b.

As a result, the terminal TA activates the group 4 facsimile communication control unit 14, and at that time the terminal TB
A group 4 facsimile transmission procedure is executed using the B channel established between the terminal and the terminal TB. When the operation of transmitting the image information of the B channel is completed, a call recovery procedure is executed to release the call.

Also, the terminal TB and the terminal TC
Is connected and the terminal TB is busy, an operation as shown in FIG. 8A is performed.

In this case, in response to the received call setup message SETUP (d, G3), the terminal TB sets release completion in which information indicating that the disconnect reason is “busy” is set in the “reason display” information element. Message REL_COM
The terminal TC sends P (d) to the ISDN, and the terminal TC sends a response message CONN (d) to the ISDN to answer the call setup message (d, G3).

As a result, the response confirmation message CONN_ACK (d) is returned from the ISDN to the terminal TC, and the release completion message REL_COMP (a) is transmitted from the ISDN to the terminal TA, so that the call related to the call number a is issued. Release and response message CON
N (b) are sequentially transmitted.

In this case, terminal TA determines that a group 4 facsimile apparatus is connected to the other party, and shifts to a group 4 standby mode re-call operation. At the same time, in order to release the B channel of the call number b established at that time, a disconnection message DISC (b) is sent to the ISDN, and a call recovery operation is performed with the terminal TC.

Further, the terminal TB and the terminal TC
Are connected, and when the terminal TB and the terminal TC are each busy, an operation as shown in FIG.

That is, the terminal TB and the terminal TC respond to the received call setup message SETUP (c, G4) and call setup message SETUP (d, G3).
Release completion message REL in which information indicating that the disconnect reason is "busy" is set in the "reason display" information element.
_COMP (c) and release completion message REL_C
Send OMP (d) to ISDN.

Thus, from the ISDN to the terminal TA,
The release completion message REL_COMP (a) is transmitted to release the call related to the call number a, and the release completion message REL_COMP (b) is transmitted to release the call related to the call number b.

In this case, terminal TA determines that a group 4 facsimile apparatus is connected to the other party, and shifts to a group 4 standby mode recall operation.

Thus, in this embodiment, the terminal TA
Sends a call setup message SETUP with group 4 facsimile function set up first and a call setup message SETUP with group 3 facsimile function set up to ISDN, and based on the call setup message received from ISDN, the group It is determined whether a 4-facsimile machine is connected.

When it is determined that the group 4 facsimile apparatus is connected to the other party and that data can be transmitted immediately, the call setting procedure with the group 3 facsimile apparatus is forcibly terminated. Data transmission is performed with the group 4 facsimile machine. If it is determined that the group 4 facsimile apparatus is connected and the group 4 facsimile apparatus is busy, the call setting procedure with the group 3 facsimile apparatus is forcibly terminated and the group 4 facsimile apparatus is forcibly terminated. The operation shifts to the re-call operation in the 4 standby mode.

On the other hand, if it is determined that there is no group 4 facsimile apparatus at the other party and only the group 3 facsimile apparatus is connected and that data transmission can be performed immediately, the data between the group 3 facsimile apparatus and the group 3 facsimile apparatus can be transmitted immediately. Perform transmission. If it is determined that only the group 3 facsimile apparatus is connected and the group 3 facsimile apparatus is busy, the operation shifts to the group 3 standby mode recall operation.

Therefore, when a group 4 facsimile apparatus is connected to the destination, image information transmission using the group 4 facsimile function is performed, so that efficient data transmission can be performed.

When only the group 3 facsimile apparatus is connected to the destination, image information transmission using the group 3 facsimile function is performed, so that the user can use the group 4 facsimile function or the group 3 facsimile function. Of these, the data transmission is performed even if the device function to be used is not specified, so that the usability of the ISDN facsimile device is improved.

FIG. 9 shows an example of processing when the ISDN facsimile apparatus of FIG. 1 performs a transmission operation from a standby state.

In this case, there is management information in which the time stored in the transmission designated time information is earlier than the current time, and the content of the transmission result information is other than “OK” or “NG”. It is determined whether the transmission result information is in the group 4 / group 3 standby mode or the group 4 standby mode when the result of the determination 101 is YES. Check (decisions 102, 103).

If the group 4 / group 3 standby mode is set (the result of determination 102 is YES), the group 4 / group 3 call setting process is started (process 10).
4) If the group 4 standby mode is set (the result of the determination 103 is YES), the group 4 call setting process is started (process 105), and if the group 3 standby mode is set ( If the result of the determination 103 is NO), the group 3 call setting process is started (process 106).

FIGS. 10 and 11 show an example of the group 4 / group 3 call setting process.

First, the content of the destination ISDN number information of the management information selected at that time is set to the content of the "destination number" information element, and the call setting message of the call number a in which the group 4 facsimile function is set as the terminal function. SET
The UP (a, G4) is formed and transmitted to the ISDN (process 201), and the content of the destination ISDN number information of the management information selected at that time is set to the content of the "destination number" information element and the terminal function Call setup message SET for call number b with group 3 facsimile function set as
Form UP (b, G3) and send it to ISDN (Process 2
02), message reception from the ISDN is performed until the response message CONN (a) or the release completion message REL_COMP (a) is received from the ISDN (process 203, NO loop of determinations 204 and 205).

Response message CONN from ISDN
When (a) is received and the result of the determination 204 is YES, it is checked whether or not the call setting operation of the call number b is being performed at that time (determination 206), and the result of the determination 206 is Y
When it becomes ES, a disconnection message DISC (b) is sent to start a call release procedure (process 207), and the ISDN
Receives the release message REL (b) from
08), a release completion message REL_COMP (b) is transmitted (process 209), and the call setting operation of the call number b is forcibly terminated.

Next, a B channel is established with the partner terminal (process 210), a group 4 facsimile transmission procedure is executed using the established B channel, and transmission image information is transmitted to the partner terminal (process 210). 211). When the image information transmission operation is completed, the B channel is released (step 21).
2), execute the call recovery procedure (process 213), release the call, set "OK" in the content of the transmission result information of the management information selected at that time (process 214), and end this process. I do.

Also, when the release completion message REL_COMP (a) is received during the call setting operation, the judgment 205
If the result of step (1) is YES, it is checked whether or not the content of the "reason display" information element is "busy" (decision 2).
15).

If the result of decision 215 is YES, it is checked whether or not the number of recalls has ended (decision 21).
6) When the result of the determination 216 is NO, the value of the number of times of call information of the management information selected at that time is increased by one (process 217), and at that time, the call setting operation of the call number b is being performed. It is checked whether or not there is (decision 218), and decision 218
Is YES, the disconnection message DIS
C (b) is sent to start the call release procedure (process 21).
9) When the release message REL (b) is received from the ISDN (process 220), the release completion message REL_C is received.
OMP (b) is transmitted (process 221), and the call setting operation of call number b is forcibly terminated.

At this time, since the group 4 facsimile apparatus is connected to the destination, the content of the transmission result information of the management information selected at that time is changed to the group 4 standby mode, and the content of the transmission designated time information is changed. Is reset to the time after the elapse of the predetermined recall time (Process 2
22), this process ends. In this case, the operation at the time of recall is a group 4 call setting processing operation.

If the result of the determination 216 is YES, the content of the transmission result information of the management information selected at that time is changed to "NG" (process 223), and this process ends.

When the result of the judgment 215 is NO, it is checked whether or not the content of the "reason display" information element is "no response from the partner terminal" (decision 224). Judgment 22
If the result of step 4 is YES, it is checked whether the response message CONN (b) or the release completion message REL_COMP (b) is included in the received call setup message (decisions 225, 226). When the result is NO, the process returns to step 203 and waits until a necessary call setup message is received.

When the response message CONN (b) is received and the result of determination 225 is YES, a B channel is established with the partner terminal (step 2).
27), using the established B channel, group 3
The facsimile transmission procedure is executed, and the transmission image information is transmitted to the partner terminal (process 228). When the image information transmission operation is completed, the B channel is released (process 229), a call recovery procedure is executed (process 230), the call is released, and the content of the transmission result information of the management information selected at that time is displayed as ""OK" is set (process 231), and this process ends.

Also, a release completion message REL_COM
When P (b) is received, the result of decision 226 is YES
, It is checked whether the content of the "reason display" information element is "busy" (decision 232).

When the result of the judgment 232 is YES, it means that the group 4 facsimile machine is not connected to the other party, and it is checked whether or not the number of re-calls has ended (judgment 233). When the answer is NO, the value of the number-of-calls information of the management information selected at that time is increased by one, and at this time, only the group 3 facsimile apparatus is connected to the other party. The content of the information transmission result information is changed to the group 3 standby mode, and the content of the designated transmission time information is reset to the time after the lapse of a predetermined recall time (process 234), and this process ends. In this case, the operation at the time of recall is a group 3 call setting processing operation.

When the result of the determination 233 is NO, the content of the transmission result information of the management information selected at that time is changed to "NG" (process 235), and this process ends.

When the result of the judgment 232 is NO, it is checked whether or not the content of the "reason display" information element is "no response from the partner terminal" (decision 236).
If the result of step 6 is YES, since neither the group 4 facsimile machine nor the group 3 facsimile machine is connected to the destination, the content of the transmission result information of the management information selected at that time is changed to "NG". Then (processing 237), this processing ends.

When the result of decision 224 is NO and when the result of decision 236 is NO,
This processing ends.

Note that the group 4 call setting process and the group 3 call setting process are the same as those of the conventional device, and therefore the description thereof is omitted.

[0121]

As described above, according to the present invention,
When the other terminal has the group 4 facsimile function, the image information transmission is performed using the group 4 facsimile function with low communication cost and good image quality of the image information. The efficiency is greatly improved. When it is determined that the partner terminal has only the group 3 facsimile function, the image information transmission using the group 3 facsimile function is performed.
There is an advantage that the call setting operation is not wasted and image information can be transmitted efficiently.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an ISDN facsimile apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of management information.

FIG. 3 is a time chart showing an example of a call setup procedure performed by an ISDN terminal device with an ISDN.

FIG. 4 is a schematic diagram showing a signal format and the like of a call setting message.

FIG. 5 is a time chart showing an example of a procedure executed by the apparatus of FIG. 1;

FIG. 6 is a time chart showing another example of the procedure executed by the apparatus of FIG. 1;

FIG. 7 is a time chart showing still another example of the procedure executed by the apparatus of FIG. 1;

FIG. 8 is a time chart showing still another example of the procedure executed by the device of FIG. 1;

FIG. 9 is a flowchart illustrating an example of a process executed by the device of FIG. 1 at the time of calling;

FIG. 10 is a flowchart showing a part of a group 4 / group 3 call setting processing example.

FIG. 11 is a flowchart showing another part of the example of the group 4 / group 3 call setting process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 System control part 2 System memory 3 Parameter memory 12 D channel control part 13 Group 3 facsimile communication control part 14 Group 4 facsimile communication control part

Claims (3)

(57) [Claims] 1. An ISDN facsimile apparatus having a group 3 facsimile function and a group 4 facsimile function, and using an ISDN as a transmission line, comprising: a first call setting message in which a group 4 facsimile function is set as a device function when a call is originated; When a second call setup message in which a group 3 facsimile function is set as an apparatus function is sequentially transmitted to the ISDN, and a call setup message having a possibility of call connection is received in response to the first call setup message, The call setting operation according to the second call setting message is aborted, the call setting procedure operation according to the first call setting message is performed, and a call that may be call-connected to the first call setting message is performed. No call setup message is received and the call connection is made in response to the second call setup message. When receiving a possible call setup message, there is provided transmission control means for terminating a call setup operation according to the first call setup message and performing a call setup procedure operation according to the second call setup message. Characteristic ISDN facsimile machine. 2. The transmission control unit determines whether a call connection is possible based on a “disconnection reason” parameter arranged in a “reason display” information element included in the received call setting message. The IS according to claim 1, wherein
DN facsimile machine. 3. The transmission control means according to claim 2, wherein said "disconnection reason"
3. The ISD according to claim 2, wherein when the value of the parameter is "busy", a recall process is started.
N facsimile machine.