JPH0514433A - Call setting control method for ISDN terminal - Google Patents

Abstract

PURPOSE:To avoid useless call setup operation and waste of a communication cost by implementing the call setup procedure only when plural information channels in use are idle. CONSTITUTION:A B-channel operating state monitor means 2a is arranged in an ISDN interface section 2 and always monitors the B-channel operating state of other terminal equipment on a same subscriber line. A B-channel state flag 4a is arranged in a system memory 4 to indicate the result of monitor of the B-channel operating state monitor means 2a at all times. While an outgoing terminal equipment checks an idle state of a B-channel at an outgoing call, a called terminal equipment checks the idle state of the B-channel at the arrival of a call and executes a prescribed setup means with an opposite terminal equipment only when plural operating B-channels are idle. Thus, in the case of outgoing and incoming, when plural B-channels in use are not idle, since the setup procedure is not executed, the useless call setup operation and the waste of communication cost are avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ISDN terminal 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 data is transmitted by simultaneously using each channel. Call setting control method.

[0002]

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

When the terminal device performs two-channel communication,
It is necessary to execute the call originating / receiving operation, that is, the call setting procedure 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 above basic interface, and each terminal shares two B channels. Therefore, 2
When a terminal device performing channel communication makes or receives a call, another terminal device connected to the line may use one of the B channels.

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, so the communication is stopped at that point. .

[0006]

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

The present invention solves the above problems and eliminates unnecessary call setting operation and communication expense.
It is an object to provide a call setup control method for N terminals.

[0008]

To this end, according to the present invention, the calling terminal checks the idle state of the information channel when making a call, while the called terminal checks the idle state of the information channel when making an incoming call. It is characterized in that a predetermined call setup procedure is executed with the partner terminal only when a check is made and a plurality of information channels to be used are available.

[0009]

[Operation] When a plurality of information channels to be used are not available at the time of making or receiving a call, the call setup procedure is not executed.
It is possible to eliminate useless call setting operations and communication costs.

[0010]

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

FIG. 1 is a block diagram of a facsimile apparatus according to an embodiment of the present invention. In the figure, the facsimile image processing unit 1 compresses image information obtained by reading a document image during image transmission, and restores received image data to original image information during reception. An image is recorded on recording paper. The ISDN interface unit 2 has a basic interface of ISDN user / network interface, and I
It is connected to one subscriber line of SDN and transmits / receives a data signal to / from ISDN. In this embodiment, a B channel use state monitoring means 2a is provided in the ISDN interface section 2. The B channel usage status monitoring means 2a constantly monitors the B channel usage status of other terminal devices on the same subscription line.
The D channel control unit 3 executes an ISDN call setup procedure.

The system memory 4 temporarily stores various information. In this embodiment, the system memory 4 stores
A B channel use status flag 4a is provided. This flag always displays the monitoring result of the B channel use status monitoring means 2a. The operation display unit 5 is for displaying various information such as the operating state of the device as the operator performs various operations. In this embodiment, the operation display section 5 is provided with B channel use condition designating means 5a for designating 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 each of the above units.

With the above configuration, the facsimile apparatus of this embodiment is connected to one ISDN subscriber line together with other terminal apparatuses. Further, this facsimile apparatus has a function of executing two-channel communication in which two B channels are simultaneously used, if necessary.

Next, the communication operation between the facsimile machines of this embodiment will be described.

On the calling terminal side, the operator, as shown in FIG.
Set the channel usage conditions. This setting specifies "essential" or "desired" when there is a request for 2-channel communication. "Mandatory" is specified when two-channel communication is required, and "hope" is specified when two-channel communication is desired. If you do not specify,
Normal communication of only one channel is used. Along with this designation, a predetermined setting such as a destination is made and the device is activated (process 10).
1).

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

Assuming that another terminal device on the same subscription line is not in communication now, both B channels are vacant. In this case (process 104
Y), the B channel usage condition ID (hereinafter, referred to as “user information” (hereinafter abbreviated as UUI) added to the call setup message “SETUP”, which declares two-channel communication.
BID).

This BID is defined together with the information used by the called side, and as shown in FIG. 3, shows various information contents by numbers. Here, BID # 4 that declares the use of two channels is set (process 105). Then, call the created UUI the call setup message "SETUP".
To the ISDN (process 106 in FIG. 4) and I
The SDN response is monitored (process 107).

The call setup message "SETUP" is
As shown in FIG. 5, it is sent to the destination terminal via ISDN.

When the destination terminal receives the call setup message "SETUP" as shown in FIG. 6 (process 201), it determines whether UUI is added to the message and the BID is set (process 202). . Now
If it is an incoming call from the calling terminal, UUI is added and BID is set. When the destination terminal receives the information (Y in process 202), the destination terminal determines the content of the BID (process 203), and if BID # 4, that is, "declaration" is specified ("declaration" in process 203), Similar to the calling terminal, the free state of the B channel is checked (process 204).

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

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

The response message "CONN" is sent to the calling terminal, thereby forming a B-channel communication link between the calling terminal and the called terminal.

The calling terminal sends the response message "CON
When "N" is received (Y in processing 107 in FIG. 4), the content of the BID of the added UUI is determined (processing 10).
8). When BID # 2, that is, "accept" (Y in process 108), B is the same as in process 105.
A UUI with ID # 4 is created (process 109), and is sent again together with the call setup message "SETUP" (process 11).
0).

The destination terminal receives the call setup message "SET" with the BID set to "# 4" within the fixed time.
When "UP" is received (Y in processing 208 in FIG. 6), the response message "CONN" is transmitted (processing 210).

This response message "CONN" is sent to the calling terminal, so that 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 the response message "CO
When "NN" is received (Y in processing 111 in FIG. 4), predetermined data transmission using two B channels simultaneously 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 sent from the calling terminal, a predetermined call disconnection procedure is executed, and the communication is terminated (process 113, process 21).
2). FIG. 5 shows a transmission procedure when two channels are simultaneously used for communication as described above.

Next, if one of the B channels is used when the incoming call is made (N in process 204), the UUI in which the BID # 3 that rejects the use of the two channels is set is set. Create (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 calling terminal receives a response indicating a call disconnection such as a release message "REL" after making the initial call (N in process 107 in FIG. 3), the call is similarly disconnected (process 1).
13). FIG. 7 shows the transmission procedure in this case.

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

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

If the destination terminal is BID # 1 (“invitation” in step 203 in FIG. 6), the usage status of the B channel is checked (step 215), and if both channels are free (step 215). Y), similarly to the above, BID # 2 indicating acceptance of two-channel communication is set (process 20).
5), the response message “CONN” is transmitted (Processing 2)
06). As a result, the transmission procedure shown in FIG. 4 is executed similarly to the above.

On the other hand, if one of the B channels is being used (N in processing 215), BID # 3 which rejects the use of two channels is set in the UUI (processing 216).
The response message "CONN" is transmitted (process 21)
7).

When the calling terminal receives BID # 3 in the response message "CONN" (N in processing 108 in FIG. 4), it sends a predetermined data to the called terminal through one B channel in which the communication link is previously formed. Perform 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 process 103 in FIG. 2), if only one B channel is vacant (N in process 115), the normal operation is performed without using UUI. To call. Further, 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 performed normally on one B channel. Furthermore, the call setup message "S
When the message for rejecting the call connection is received after sending "ETUP" (N in process 107), the call is immediately disconnected (to process 113).

As described above, in this embodiment, when the two-channel communication is set to be indispensable, the calling terminal checks the usage state of the B channel and does not make a call when the B channel is also used. I am trying. Also, the called terminal checks the usage state of the B channel when the incoming call is made and the two-channel communication is declared, and when the other side is also used, the call is immediately disconnected. As a result, it is possible to prevent the useless call setting operation as in the past from being executed,
It is possible to eliminate waste of communication costs when executing the call setup.

At the calling terminal, the operator specifies conditions such as "essential" or "desired" for the two-channel communication, and the facsimile machine performs an operation corresponding to the condition and the idle state of the line. The operating condition is notified to the destination terminal. This allows the operator to freely select the communication method as necessary.

Further, since information about the necessity of two channels and communication availability is transferred between the calling terminal and the called terminal by using the UUI, a special transmission control procedure is not required and the B channel is used. There is no increase in communication charges.

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

Although the facsimile apparatus has been described as an example, the present invention can be similarly applied to various data terminal apparatuses.

[0041]

As described above, according to the present invention, the calling terminal checks the idle state of the information channel when making a call, while the called terminal checks the idle state of the information channel when receiving a call. By checking and executing the predetermined call setup procedure with the other terminal only when the multiple information channels to be used are free, it is possible to eliminate unnecessary call setup operations and communication costs. .

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a facsimile apparatus according to an 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 setup 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 2-channel communication.

FIG. 6 is an operation flowchart of the 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 by one channel.

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

[Explanation of symbols]

1 Facsimile image processing unit 2 ISDN interface section 2a B channel use status monitoring means 3 D channel controller 4 system memory 4a B channel use status flag 5 Operation display section 5a B channel use condition designating means 6 System control unit

Claims (5)

[Claims] 1. A call setup control method for an ISDN terminal 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 data is simultaneously transmitted using each channel. The ISDN is characterized in that the calling terminal checks the idle state of the information channel at the time of calling, and calls the called terminal to execute the call setup procedure only when a plurality of information channels to be used are idle. Call setup control method for terminals. 2. The receiving terminal checks the idle state of the information channel at the time of an incoming call, and executes the call setup procedure with the calling terminal only when a plurality of information channels to be used are idle. Item 1. A call setup control method for an ISDN terminal according to item 1. 3. The calling terminal notifies the called terminal of the number of channels to be used when executing the call setting procedure, and the called terminal and the call setting procedure only when the notified number of information channels is vacant. ISDN according to claim 1, characterized in that
Call setup control method for terminals. 4. The call setting control method for an ISDN terminal according to claim 3, wherein the number of channels is notified from the calling terminal to the called terminal based on the user / user information of the call setting message. 5. The call setting control method for an ISDN terminal according to claim 3, wherein the calling terminal is provided with means for arbitrarily setting the number of information channels to be used.