JP3169235B2 - ISDN terminal device and call setting control method therefor - 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 terminal device in which a calling terminal and a called terminal execute a call setting procedure a plurality of times to form a communication link of a plurality of information channels and transmit data using each channel simultaneously. And its call setting control method.

[0002]

2. Description of the Related Art A basic interface of an ISDN user / network interface has one D channel for call control and two B channels for information transmission. well known. Through such two-channel communication, a large amount of data can be transmitted in a short time, and in the case of a videophone terminal, a partner image can be simultaneously viewed.

When a terminal device performs two-channel communication,
The outgoing / incoming operation, that is, the call setting procedure must be executed twice. That is, one B-channel communication link is formed with the destination terminal at the first time, and the other B-channel communication link is formed at the second time.

In ISDN, a maximum of eight terminal devices are connected to the subscriber line of the basic interface, and each terminal shares two B channels. Therefore, 2
When a terminal device performing channel communication initiates or receives a call, another terminal device connected to the line may use one of the B channels.

[0005] In this case, the terminal device that performs two-channel communication forms one communication link in the first call setup procedure, but the second call setup procedure fails, and the communication is stopped at that time. .

[0006]

Therefore, there is a problem that the operation of forming one communication link is wasted, and that a communication charge is required for the time of the call setting operation, thereby wasting communication cost. .

[0007] The present invention solves the above-mentioned problems, and eliminates wasteful call setting operations and communication cost waste.
It is an object of the present invention to provide an N terminal device and a call setting control method thereof.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided an ISDN in which a calling terminal and a called terminal execute a call setting procedure a plurality of times to form a communication link of a plurality of information channels, and perform data transmission using each channel simultaneously. In the terminal device, the calling terminal checks the availability of information channels at the time of calling, and calls the called terminal only when the number of used information channels is equal to or more than the specified number of used channels to perform a call setting procedure. Executing, while providing first call setting procedure control means for notifying the called terminal of the number of channels used during the call setting procedure, the called terminal checks the free state of the information channel at the time of the incoming call,
A second call setting procedure control means for executing a call setting procedure with the calling terminal only when there are available information channels equal to or more than the number of used channels specified by the calling terminal. A call setting control method for an ISDN terminal device in which a calling terminal and a called terminal execute a call setting procedure a plurality of times to form a communication link of a plurality of information channels and transmit data using each channel simultaneously. Checks the availability of information channels at the time of outgoing call, calls the destination terminal to execute the call setup procedure only when the number of information channels equal to or greater than the specified number of used channels is available, and During the setup procedure, the called terminal is notified of the number of channels used,
When an incoming call is received, the information channel is checked for a free state, and the call setting procedure is executed with the calling terminal only when the number of used information channels is equal to or greater than the number of channels used by the calling terminal. The number of channels is reported from the calling terminal to the called terminal by a user / user information element of a call setup message. Further, the originating terminal is provided with means for arbitrarily setting the number of information channels to be used.

[0009]

Therefore, at the time of outgoing / incoming call, the call setting procedure is executed only when the number of information channels equal to or more than the specified number of used channels is free, so that useless call setting operation is suppressed and It is possible to prevent communication costs from being unnecessarily increased.

[0010]

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

FIG. 1 is a block diagram showing a facsimile apparatus according to an embodiment of the present invention. In FIG. 1, a facsimile image processing unit 1 compresses image information obtained by reading a document image when transmitting an image, and restores received data to original image information when receiving an image. The image is recorded on recording paper. The ISDN interface unit 2 has a basic interface of an ISDN user / network interface, and receives an IDN via a network terminating device.
It is connected to one subscriber line of the SDN and transmits and receives data signals to and from the ISDN. In the present embodiment, a B channel use state monitoring means 2a is provided in the ISDN interface unit 2. The B channel use state monitoring means 2a constantly monitors the B channel use state of another terminal device on the same subscriber line.
The D channel control unit 3 executes an ISDN call setting procedure.

The system memory 4 temporarily stores various information. In the present embodiment, the system memory 4
A B channel use state flag 4a is provided. This flag always displays the monitoring result of the B channel use state monitoring means 2a. The operation display section 5 is used by the operator to perform various operations, and displays the operation state of the apparatus. In the present embodiment, the operation display unit 5 is provided with a B-channel use condition specifying means 5a for specifying the use condition of the B-channel when the operator makes a call. The system control unit 6 is a microcomputer that monitors and controls the above units.

With the above configuration, it is assumed that the facsimile apparatus of this embodiment is connected to one subscriber line of the ISDN together with another terminal apparatus. Further, the facsimile apparatus has a function of executing two-channel communication using two B channels simultaneously as necessary.

Next, the communication operation between the facsimile apparatuses of the present embodiment will be described.

On the calling terminal side, as shown in FIG. 2, the operator sends a B to the facsimile machine when making a call.
Set the conditions for using the channel. This setting specifies "essential" or "desired" when there is a request for two-channel communication. “Indispensable” is specified when two-channel communication is required, and “desired” is specified when two-channel communication is desired if possible. If not specified,
Normal communication of only one channel is performed. Along with this designation, the device is started by performing predetermined settings such as the destination (process 10).
1).

When the facsimile apparatus is started, it checks whether or not the use condition of the B channel is specified (step 10).
2) If specified (Y in process 102), the specified content is determined (process 103). If it is assumed that the use of the two channels is “required” (“required” in the processing 103), the use state of the B channel is checked. The B channel usage status is constantly monitored by the B channel usage status monitoring means 2a, and the monitoring result is set in the B channel usage status flag 4a. The above check is performed by reading the B channel use state flag 4a (process 104).

Assuming that no other terminal device on the same subscribed line is operating for communication, both B channels are vacant. In this case (step 104
Y), B-channel use condition ID (hereinafter, referred to as UUI) declaring 2-channel communication as user / user information (hereinafter abbreviated as UUI) to be added to the call setup message “SETUP”.
BID).

The BID is defined together with information used by the called side, and indicates various information contents by numbers as shown in FIG. Here, BID # 4 declaring use of two channels is set (process 105). Then, the created UUI is displayed in the call setup message “SETUP”.
To the ISDN (FIG. 4, process 106).
The response of the SDN is monitored (process 107).

The above-mentioned call setup message “SETUP”
As shown in FIG. 5, the packet is transmitted to the destination terminal via the ISDN.

When the called terminal receives the call setup message "SETUP" as shown in FIG. 6 (step 201), it adds a UUI to the message and determines whether a BID is set (step 202). . Now
If it is an incoming call from the calling terminal, a UUI is added and a BID is set. Upon receiving the information (Y in process 202), the called terminal determines the content of the BID (process 203). If BID # 4, that is, “declaration” is designated (“declaration” in process 203), In the same manner as in the calling terminal, the vacant state of the B channel is checked (step 204).

If both B channels are vacant (Y in step 204), a BUI # 2, that is, a UUI designating "accept" of two-channel communication is created (step 205). Then, the UUI is added to the response message "CONN" and transmitted to ISDN (process 20).
6).

Next, a timer is started (process 2).
07) The reception of the call setup message “SETUP” is monitored for a predetermined time set in the timer (from processing 208, N in processing 208 to processing 209, and from N in processing 209 to processing 208).

The response message "CONN" is sent to the calling terminal, whereby a communication link of one B channel is formed between the calling terminal and the called terminal.

The calling terminal sends the response message "CON
N ”(FIG. 4, Y in step 107), the contents of the BID of the added UUI are determined (step 10).
8). If BID # 2, that is, “accept” (Y in step 108), BID
A UUI with ID # 4 is created (step 109), and sent again together with the call setup message "SETUP" (step 11).
0).

The called terminal transmits the above-mentioned call setting message “SET” in which “# 4” is set in the BID within the predetermined time.
When "UP" is received (Y in step 208 in FIG. 6), a response message "CONN" is sent out (step 210).

The response message "CONN" is sent to the calling terminal, whereby a communication link is simultaneously formed between the calling terminal and the called terminal by another B channel.

At this point, the calling terminal sends a response message "CO
When "NN" is received (Y in processing 111 in FIG. 4), predetermined data transmission using two B channels at the same time is executed with the destination terminal (processing 112, processing 211 in FIG. 6).
Then, when the data transmission is completed, for example, a disconnection message "DISC" is transmitted from the calling terminal, a predetermined call disconnection procedure is executed, and the communication is terminated (steps 113 and 21).
2). FIG. 5 shows a transmission procedure in the case where communication is performed using two channels simultaneously as described above.

Next, if one of the B channels is in use at the time of the above-mentioned incoming call (N in step 204), the UUI in which BID # 3 for rejecting the use of the two channels is set. It is created (process 213). And that U
The UI is added to the release message "REL" and transmitted (process 214). As a result, the call is immediately disconnected (to process 212).

When the originating terminal receives a response indicating a call disconnection such as a release message "REL" after the initial call origination (N in process 107 in FIG. 3), it similarly disconnects the call (process 1).
13). FIG. 7 shows a transmission procedure in this case.

If one of the B channels is used on the calling terminal side (N in process 104), it is displayed that two-channel communication cannot be executed (process 114), and the operation ends. .

Next, at the calling terminal, the operator
It is assumed that the use condition of the channel is specified as “desired”. In this case (FIG. 2, “desired” in process 103), the use state of B channel is checked (process 115), and if both channels are free (Y in process 115), BID # inviting use of two channels 1 is set in the UUI (process 116).
Then, similarly, a call setup message "SETUP" is transmitted (process 106).

If the destination terminal is BID # 1 ("solicitation" in process 203 in FIG. 6), the use state of the B channel is checked (process 215), and if both channels are free (process 215). Y) In the same manner as described above, BID # 2 indicating acceptance of two-channel communication is set (processing 20).
5) Send a response message “CONN” (Process 2)
06). Thus, the transmission procedure shown in FIG. 4 is executed in the same manner as described above.

On the other hand, if one of the B channels is used (N in step 215), BID # 3 for which use of the two channels is rejected is set in the UUI (step 216).
Sends a response message "CONN" (Process 21)
7).

When the originating terminal receives BID # 3 in the response message "CONN" (N in process 108 in FIG. 4), the originating terminal and the destination terminal communicate with predetermined data on one B channel on which a communication link has been formed first. Execute transmission (process 117, FIG. 6)
-Process 218). FIG. 8 shows a transmission procedure in this case.

On the other hand, at the calling terminal, the operator
Although the use condition of the channel is designated as "desired"("desired" in the processing 103 in FIG. 2), if only one channel is available (N in the processing 115), the normal operation without using the UUI is performed. Call. Even when the operator does not specify the use condition of the B channel, the call is made in the normal operation. As a result, data transmission is normally performed on one B channel. Further, the call setup message "S
If a message rejecting the call connection is received after the transmission of the "ETUP" (N in process 107), the call is immediately disconnected (to process 113).

As described above, in the present embodiment, when the two-channel communication is set to be essential, the calling terminal checks the use state of the B channel, and does not make a call if only one is used. Like that. Also, the called terminal checks the use state of the B channel when the call is received and the two-channel communication is declared, and immediately terminates the call when one of the terminals is used. This prevents the useless call setting operation of the related art from being performed, and
It is possible to eliminate waste of communication costs when executing the call setting.

At the calling terminal, the operator specifies conditions such as "essential" and "desired" with respect to two-channel communication, and the facsimile apparatus performs an operation corresponding to the conditions and the line availability and , The operating condition is notified to the receiving terminal. This allows the operator to freely select a communication method as needed.

Further, since information on the necessity of two channels and communication availability is transferred between the originating terminal and the destination terminal using the UUI, a special transmission control procedure is not required, and the B channel is used. The communication fee does not increase.

In the above embodiment, the number of B channels is 2
The case of the basic interface of the ISDN user / network interface of the channel has been described as an example. For example, in the primary interface, there are 23 B channels. In the case of supporting such another interface, the calling terminal sets the number of channels used together with the BID in the UUI of the call setup message “SETUP” as shown in FIG. 8, and the called terminal is specified by the UUI. It may be determined whether the number of used channels is vacant.

Also, the facsimile apparatus has been described as an example, but the present invention is naturally applicable to various data terminal apparatuses.

[0041]

As described above, according to the present invention,
In an ISDN terminal device in which a calling terminal and a called terminal execute a call setting procedure a plurality of times to form a communication link of a plurality of information channels, and perform data transmission using each channel simultaneously, the calling terminal performs Checks the idle state of the information channel, calls the destination terminal and executes the call setup procedure only when the number of information channels equal to or greater than the specified number of used channels is available, and calls the destination terminal during the call setup procedure. While the first terminal has the first call setting procedure control means for notifying the number of used channels, the called terminal checks the vacant state of the information channel at the time of the incoming call, and determines that the number of used information channels is equal to or more than the number of used channels specified by the calling terminal. Since it has the second call setup procedure control means for executing the call setup procedure with the calling terminal only when it is free,
At the time of outgoing / incoming call, the call setting procedure is executed only when information channels equal to or more than the specified number of used channels are available, and as a result, unnecessary call setting operation is suppressed and communication cost is reduced. The effect is obtained that bulking is prevented. A call setting control method for an ISDN terminal device in which a calling terminal and a called terminal execute a call setting procedure a plurality of times to form a communication link of a plurality of information channels and transmit data using each channel simultaneously. Checks the availability of information channels at the time of outgoing call, calls the called terminal only when the number of available information channels is equal to or greater than the specified number of used channels, executes the call setup procedure, and During the setup procedure, the called terminal is notified of the number of channels used,
The called terminal checks the free state of the information channel when receiving a call, and executes the call setting procedure with the calling terminal only when the number of information channels equal to or more than the number of used channels specified by the calling terminal is free. Therefore, when an outgoing / incoming call is made, the call setting procedure is executed only when information channels equal to or more than the specified number of used channels are available. As a result, unnecessary call setting operation is suppressed, and communication costs are reduced. Is prevented from being unnecessarily increased.

[Brief description of the drawings]

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

FIG. 2 is a part of an operation flowchart of a calling terminal.

FIG. 3 is an explanatory diagram of user / user information added to various call setting messages.

FIG. 4 is another part of the operation flowchart of the calling terminal.

FIG. 5 is an explanatory diagram showing a transmission procedure when performing two-channel communication.

FIG. 6 is an operation flowchart of a destination terminal.

FIG. 7 is an explanatory diagram showing an example of a transmission procedure when a call is rejected and the call is disconnected.

FIG. 8 is an explanatory diagram showing an example of a transmission procedure when communicating on one channel.

FIG. 9 is an explanatory diagram of user / user information added to a call setting message in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Facsimile image processing part 2 ISDN interface part 2a B channel use state monitoring means 3 D channel control part 4 System memory 4a B channel use state flag 5 Operation display part 5a B channel use condition designation means 6 System control part

Claims (4)

(57) [Claims] 1. An ISDN terminal device in which a calling terminal and a called terminal execute a call setup procedure a plurality of times to form a communication link of a plurality of information channels and transmit data using each channel simultaneously. Checks the availability of information channels at the time of outgoing call, calls the destination terminal and executes the call setup procedure only when information channels equal to or greater than the specified number of used channels are available. A first call setting procedure control means for notifying the called terminal of the number of used channels to the called terminal, while the called terminal checks the free state of the information channel at the time of the incoming call, and determines the number of used channels specified by the calling terminal. An ISDN terminal device comprising second call setup procedure control means for executing a call setup procedure with a calling terminal only when the above information channel is free. 2. A call setting control method for an ISDN terminal device in which a calling terminal and a called terminal execute a call setting procedure a plurality of times to form a communication link of a plurality of information channels and transmit data using each channel simultaneously. The calling terminal checks the availability of the information channel at the time of calling, and calls the called terminal to execute the call setup procedure only when the number of information channels equal to or greater than the specified number of used channels is available. During the call setup procedure, the called terminal notifies the called terminal of the number of used channels, while the called terminal checks the availability of information channels at the time of the incoming call, and if the number of used information channels is equal to or greater than the number of used channels specified by the calling terminal. A call setting control method for an ISDN terminal device, wherein a call setting procedure is performed with a calling terminal only when the call is free. 3. The IS according to claim 2, wherein the number of channels is notified from the calling terminal to the called terminal by a user / user information element of a call setup message.
A call setting control method for a DN terminal device. 4. The method according to claim 2, wherein said originating terminal is provided with means for arbitrarily setting the number of information channels to be used.