JPH03179956A - Transmission control method for isdn terminal equipment - Google Patents

Abstract

PURPOSE:To perform call connection with a host device by sending a response message immediately after judging the availability of its own terminal when it can use the content of transmission mode information, and sending the response message after the lapse of constant time when it cannot use the information. CONSTITUTION:An outgoing terminal sets a terminal function to be used, and also, issues a request to perform call setting with an incoming terminal by sending a call setting message SETUP in which the incoming terminal is designated as a destination to an ISDN. The incoming terminal, when detecting an incoming call, sends a call message ALERT to the ISDN successively at a prescribed interval when its own terminal is set at an incoming receivable state, and the ISDN informs the start of the call of the incoming terminal by sending the call message ALERT to the outgoing terminal. The ISDN confirms the response of the incoming terminal by sending a response confirmation message CONN ACK to the incoming terminal, and at that time, an information channel (B channel) for data transmission between the outgoing terminal and the incoming terminal can be established.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transmission control method for an ISDN terminal device that uses SDN as a transmission path.

[Prior Art] The basic interface of ISDN includes two information channels (B channels) used for data transmission and a signal channel (B channel) used mainly for exchanging signals (messages) for call connection. D channel) is multiplexed.

In addition, if the connection on the terminal device side of the basic interface is configured as a passive bus, up to 8 ISDN terminal devices can be connected to the same basic interface, and these ISDN terminal devices can be connected to the same basic interface.
Two information channels can be used optionally by the DN terminal.

In this way, one basic interface can have multiple I
Since SDN terminal equipment can be connected, the call setup message sent from the network for making a call includes a "transfer capability" information element, a "high layer compatibility" information element, and a "low layer compatibility" information element. The called terminal refers to these information elements included in the received call setup message and accepts the call. It is determined whether or not the terminal can accept the call, and only terminals that can accept the call execute the subsequent call setup procedure.

[Problems to be Solved by the Invention] However, such conventional methods have the following disadvantages.

In other words, if multiple devices with the same terminal standard are connected to the same basic interface, such as when multiple group 4 facsimile devices are connected, all of those multiple ISD and N terminal devices Since it is now ready to receive a call, each ISDN terminal device sends a response message to the network at an appropriate timing indicating acceptance of the call.

At this time, the network validates only the first response message received and invalidates the other response messages.

and the ISDN that sent the invalidated response message.
The terminal is instructed not to perform a call setup operation by sending a release message.

On the other hand, Group 4 facsimile devices are assigned a plurality of classes depending on the device function, and devices in a higher class can perform data transmission to devices in a lower class.

Therefore, if a mix of "binary class" and "lower class" devices are connected to the same interface, when a call setup message notifying a call from a group 4 facsimile device is received, all of those group 4 facsimile devices responds to the incoming call and sends out a response message.

If the device characteristics happen to be such that a device in a lower class sends a response message at an earlier timing than a device in a higher class, unless the device in the lower class is already connected to a call, , when a call is made to that destination, a call connection is always made with a device in a lower class, so even if the calling terminal is a device in a higher class, data transmission is not performed between devices in a lower class. However, there have been cases where an inconvenience has arisen in that the operator of the originating terminal cannot transmit the data as intended.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a transmission control method for an 'fSDN terminal device that enables call connection with a target device.

[Means for Solving the Problems] According to the present invention, a calling terminal sets information representing a transmission mode to be used in the user-user information element of a call setting message, and a receiving terminal sets a user-user information element in a received call setting message.
When a user information element is included, the transmission mode information set in it is retrieved, and if the own terminal can use the contents of the transmission mode information, a response message is sent immediately after determining that the transmission mode information is If the content of the message is not usable by the own terminal, a response message is sent after a certain period of time has elapsed since the determination.

[Effect] Therefore, even if multiple terminal devices with the same equipment standard are connected to the same interface, the terminal that can use the transmission mode of the originating terminal will respond first. Even when a device is connected, a call connection can be made to a device of a higher class.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a facsimile machine according to an embodiment of the present invention. This facsimile machine uses ISDN as a transmission line and has both group 3 facsimile machine functions and group 4 facsimile machine functions.

In the figure, a control unit 1 executes operation control processing of the facsimile machine, group 3 facsimile transmission procedure processing, group 4 facsimile transmission procedure processing of the upper layer, and call procedure processing, and a system memory 2 , stores a processing program executed by the control unit 1 and various data necessary for executing the processing program, and constitutes a work area of the control unit 1. The parameter memory 3 is for storing various types of information specific to this facsimile machine, and is stored from a rewritable nonvolatile semiconductor storage device such as a battery-backed SRAM (static random access memory). Become.

The character generator 4 is for generating image data of graphic characters to be added to an image or for forming a transmission image, and the clock circuit 5 is for obtaining current time information.

The scanner 6 is for reading the original image at the resolution set in the group 4 facsimile device,
The plotter 7 records and outputs images at the resolution set in the group 4 facsimile device.

The operation display section 8 is used to operate the facsimile machine, and includes various operation keys and various display devices such as a liquid crystal display for displaying guidance information to the operator.

The encoding/decoding unit 9 encodes and compresses the image signal using a predetermined encoding method, and also decodes the encoded and compressed image information into the original image signal, and performs pixel density conversion. Part] O is for converting the pixel densities of the images of the scanner 4 and plotter 5 and the image that can be transmitted by the destination terminal device, when the pixel densities of the images are different.

The image storage device 11 is for storing various information such as a transmitted image signal, transmitted image information, received image information, and received image signal.

The ISDN interface circuit 12 is T, SDN
The layer 1 signal control unit 13 has the ISDN layer 1 signal processing function and the integration of the D channel (signal channel) signal and two B channel (information channel) signals. /It is equipped with a separation function.

The D channel transmission control unit 14 uses the D channel to
It is used to perform transmission control processing such as call control processing performed with the DN, and C0DEC15 is used to perform signal conversion processing between analog signals and digital data for transmitting analog signals using the ISDN B channel. It is.

- The B channel transmission control unit 16 transmits the ISDN B channel (
This is for performing transmission control processing of layers 2, 3, and 4.5 of group 4 facsimile transmission control processing using the information channel).

Note that in this case, the layer 1 signal control section 13 and the D channel transmission control section 14 are realized by the same LSI device. Further, the layer 1 signal control unit 13 controls the C0DE
Two B channels are allocated to C15 and B channel transmission control section 16 in any combination.

The group 3 facsimile modem 17 is for realizing the group 3 facsimile modem function, and has a low speed modem function (V,
21 modem), and high-speed modem function (V, 29 modem, V, 27te) mainly for exchanging image information.
r modem).

The switch 18 is used to switch and connect the CODEC 15 to either the group 3 facsimile modem 17, the handset 19 for calling, or the speaker 20 for outputting a ring tone or the like.

Control unit 1, system memory 2, parameter memory 3, character generator 4, time opening circuit 5, scanner 6, plotter 7, operation display unit 8, encoding/decoding unit 9, pixel density conversion unit 10, image storage device ILD channel Transmission control section 1
4, the C0DEC 15, the B channel transmission control section 16, the group 3 facsimile modem 17, and the switch 18 are connected to an internal bus 21, and exchange of various information between these elements is mainly carried out through this internal bus. 2
1. Further, a hook signal FS representing the hook state of the handset 19 is applied to the control unit l via the internal bus 21.

Here, the ISDN terminal such as this facsimile machine
The call setup/call release procedure performed with the ISDN during data transmission will be explained.

That is, as shown in Fig. 2, the originating terminal first sets the terminal functions to be used, and sends a call setup message 5ETUP specifying the destination terminal to the ■SDN to set up a call with the destination terminal. The ISDN then sends a call setup message 5ETUP in which the identification information (ISDN address) of the originating terminal and the terminal functions are set to the specified destination terminal, and makes a call. Further, the ISDN sends a call setup acceptance message CALL-PROC to the originating terminal to notify the call setup status.

When the destination terminal detects an incoming call, it sends a paging message ALE to the ISDN if it is ready to receive the call.
RT is sent out continuously at predetermined intervals, and the SDN sends out a paging message ALERT to the calling terminal to notify that it has started calling the called terminal.

When the destination terminal responds to the incoming call, it sends a response message C0NN to I
The ISDN sends a response message C0NN to the calling terminal to notify that the called terminal has accepted the call.

In addition, ISDN sends a response confirmation message C0N to the destination terminal.
NJCK is sent and the response of the destination terminal is confirmed, at which point an information channel (B channel) for data transmission is established between the originating terminal and the destination terminal.

As a result, data transmission between the originating terminal and the destination terminal using the information channel is performed according to the transmission control procedure set in the transmission function of each terminal.

When the data transmission is finished, the originating terminal sends a disconnection message DISC to the ISDN to request release of the information channel, and the ISDN sends a disconnection message DISC to the destination terminal to notify that the information channel has been restored.

As a result, when the destination terminal responds to the ISDN with a release message REL notifying completion of channel disconnection, the ISDN sends a release message REL to the originating terminal. When the channel release is completed, the originating terminal sends a release completion message RE.
I4. - COMP to inform the ISDN by sending a release completion message REI,
By sending COMP to the destination terminal, the information channel is released, and the information channel set between the originating terminal and the destination terminal is completely released.

In this way, an information channel is set up between the originating terminal and the destination terminal, data transmission is performed, and when the data transmission is completed, the information channel is released.

12 In addition, each message for ISDN call setup is
As shown in Figure 3(a), a protocol identifier identifies the protocol specifications (format, sequence, etc.) that define a layer 3 call control message, and identifies which call the message is related to. message type to identify the content of each message, essential information elements that are always added to each message, and additional information elements that are added to each message as necessary.

Note that required information elements can be 0 or 0 depending on the message type.
1. or multiple items are set, and the additional information element is
Depending on the situation, 0, 1, or a plurality of numbers are arranged.

As shown in FIG. 5(b), the call setup message 5ETUP has "transmission capability" as an essential information element, and additional information elements include, for example, "calling number,""terminatingnumber," and "lower layer compatibility." ”, “Higher Layer Consistency”, and “
It has information elements such as "User/User".

An outline of these information elements will be explained below.

The "transmission ability" information element indicates whether the content of the information to be transmitted is voice, unrestricted digital information, restricted digital information, 3, IKH
Information transfer ability indicating whether it is z audio, 7Kllz audio, or video, transfer mode indicating whether the switching function used is circuit switching or packet switching, and information transfer rate indicating the speed of information transfer. , information representing the information transfer format, and information representing the user information protocol.

The "calling number" information element indicates the ISDN number of the calling terminal, and the "terminating number" information element indicates the ISDN number of the called terminal.

The "lower layer compatibility" information element is used to check the possibility of communication with a partner terminal, and its basic content is the same as the "transmission capability" information element.

Furthermore, this "lower layer compatibility" information element includes more detailed content.

The "higher layer consistency" information element is used to check consistency with the other party's terminal, and is used for group 2/group 3 facsimile, group 4 facsimile, mixed mode, teletex, videotex, telex,
Alternatively, it displays which message handling system is provided as a terminal function.

The "User-User" information element is used to convey information between users, and the contents of this "User-User" information element are transparently transferred to the other user without being interpreted by the ISDN. communicated.

FIG. 4 shows an example of processing executed at the time of transmission.

When the operator places a document to be sent on the scanner 6, inputs the destination, sets the transmission function to be used, and inputs a command to start transmission (process 101), the transmission function set at that time is set to the transmission mode. At that time, the image of the transmission document set in the scanner 6 is read, the image signal obtained thereby is encoded in the encoding/decoding section 9, and the image information obtained thereby is stored as an image. It is stored in the device 11 (process 103).

15- When preparations for transmission are completed in this way, the call setup message 5ETUP for calling the destination is sent to the ISDN with the information representing the transmission mode determined in process 102 set in the "User/User J information element." Send (process 104
).

This allows you to perform call setup procedures with the ISDN (
Process 105), Process 106) to establish a communication path for an information channel with the other party's terminal, execute a predetermined group 4 facsimile procedure using the established communication path, and download the images stored in the image storage device 11. Send information to a destination (
Process 107).

When the image information transmission is completed in this manner, a call release procedure is executed with the SDN (process 10g), and the series of image information transmission processing is completed.

FIG. 5 shows an example of processing when detecting an incoming call.

Upon receiving the call setup message 5ETUP from the ISDN,
When an incoming call is detected, the content of the call setting message 5ETUP is referred to to determine whether the calling terminal and the terminal function match (Judge 201), and if the result of the decision 201 is NO, the incoming call is ignored (processing). 202).

16 When the result of decision 201 is YES, check whether the call setup message 5ETUP received at that time contains the "user-user" information element (decision 20).
3) When the result of the decision 203 is YES, the "user-user" information element includes information representing the transmission mode, and it is checked whether the transmission mode can be used (decision 204).

If the result of the judgment 204 is YES, immediately send a response message C0NN to the ISDN (process 205).
, executes subsequent call setting procedures (process 206), and establishes a communication path using an information channel with the other terminal (process 207).

Then, using the established communication path, a predetermined group 4 facsimile procedure is executed to transmit image information (process 208). In this case, in the call setup message 5ETUP, "
A transmission mode is used according to the content of the transmission mode information included in the "User-User" information element.

When the image information transmission is completed in this manner, a call release procedure is executed with the SDN (process 209), and a series of processes upon detecting an incoming call are completed.

Furthermore, if the transmission mode information included in the "user-user" information element cannot be used and the result of judgment 204 is NO, the call setup procedure is executed after waiting until a certain period of time has elapsed (process 210). Processing 211),
When a communication path is thereby established (process 212
), a predetermined group 4 facsimile procedure is executed using the communication path, and image information is transmitted (process 208).

When the image information transmission is completed, a call release procedure is executed with the ISDN (process 214), and the series of processes upon detecting an incoming call is completed.

Furthermore, if the call setup message 5ETUP does not include the "user-to-user" information element and the result of determination 203 is No, the process moves to process 211 and the subsequent processes are executed to communicate with the other party's terminal. The image information transmission operation is performed between.

In this way, when a call setup message 5ETUP is received and it contains a "User-User" information element, the transmission mode set in the "User-User" information element is used, if available. , Immediately after the determination, the call setting procedure is started by responding with a response message C0NN.

Furthermore, if the transmission mode set in the "user-user" information element cannot be used, the call setup procedure is started immediately after a certain period of time has elapsed from the determination.

Therefore, since a terminal device that can use the transmission mode of the originating terminal responds to the incoming call first, the ISDN determines that terminal device as the destination terminal and establishes a communication path with the originating terminal.

As a result, a terminal that has the same "transmission capability" information element, "high layer compatibility" information element, and "low layer compatibility" information element, and can use the transmission mode of the originating terminal, Image information can be transmitted to and from the terminal.

Note that if the "user-user" information element is not included, the normal operation when detecting an incoming call is performed.

With the above configuration, for example, as shown in FIG.
Two groups of 4F9-Kushimi devices GFA and GFB are connected to the network termination device NTa of the network termination device NTa.
Tb with two group 4 fax machines GFC, GF
A case will be described in which group 4 facsimile device GFA calls group 4 facsimile device GFC when group 4 facsimile device GFC is connected.

In this case, the group 4 facsimile machines GFA, G
FB, GFC is 400 (pixel/25.4+nm)
It is a Class 3 device with a reading/recording resolution of
Group 4 facsimile device GFD has 200 (pixels/2
Class I with reading/recording resolution of 5.4mm)
It is a device.

As shown in FIG. 7, Group 4 facsimile device GF
A sends the ISD of the network termination device NTb with information specifying a resolution of 400 (pixels/25.4 mm) set as transmission data information in the "User-User" information element.
Call setup message 5ETU calling terminal with N address
P to the ISDN, and the ISDN sends the network termination equipment fiNT
From b, the call setting message 5ETUP is sent to the terminal side in broadcast format.

This causes group 4 facsimile device GFc.

Each GFD receives its call setup message 5ETUP and determines the content of its information elements.

In this case, 400
Since the information specifying the resolution of (pixels/25.4 mm) is set, the Group 4 facsimile device GFC
The transmission mode of the group 4 facsimile device GFD is inconsistent, and the transmission mode of the group 4 facsimile device GFD is inconsistent.

Therefore, the group 4 facsimile device GFC sends a response message C0NN to the ISDN immediately after making this determination.
Group 4 facsimile device GFD sends the response message C0NN to IS after time Ta has elapsed since the determination.
Send to DN.

As a result, the ISDN performs call setup procedures on the group 4 facsimile equipment GFC and forms a communication path with the group 4 facsimile equipment GFA, which is the calling terminal, and as a result, the group 4 facsimile equipment GFC Data transmission is carried out between device GFA and group 4 facsimile device GFC.

On the other hand, ISDN uses Group 4 facsimile equipment GFD
When receiving the response message C0NN from the group 4 facsimile device GFD, it sends a release message ItCI to the group 4 facsimile device GFD in order to restore the call.

As a result, the group 4 facsimile device GFD sends release completion messages REI and COMP, and ends the operation upon detecting an incoming call.

In this way, in this case, a communication path is established between the group 4 facsimile device GFA and the group 4 facsimile device GFC, which have the same transmission mode, and
Group 4 facsimile device G with mismatched/matched transmission modes
Since the FD enters the call recovery state, image information transmission using the transmission function intended by the operator of the originating terminal is executed.

As explained above, in this embodiment, even if multiple devices with the same standard and different transmission functions are connected to the same user/network interface, communication between the calling terminal and the device with the same transmission function is possible. Since the path is established, data transmission as intended by the operator of the originating terminal can be performed appropriately.

In addition, in the two embodiments, the present invention is applied to a group 4 facsimile device, but the present invention can be similarly applied to other devices.

In addition, in the two consecutive embodiments, the present invention was applied to a device connected to ISDN 1 (this interface), but the present invention can be similarly applied to devices connected to other ISDN interfaces. can do.

[Effects of the Invention] As explained above, according to the present invention, even when a plurality of terminal devices of the same device standard are connected to the same interface, a terminal that can use the transmission mode of the originating terminal responds first. Therefore, the terminal is identified as the destination terminal and subsequent call connections are made, thereby achieving the effect that the data transmission intended by the operator of the originating terminal can be reliably carried out.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a facsimile apparatus according to an embodiment of the present invention, FIG.
) is a schematic diagram showing the format of a call setup message;
) is a schematic diagram showing an example of information elements of a call setup message;
FIG. 4 is a flowchart 1 showing an example of processing when making a call, FIG. 5 is a flowchart 1-1 showing an example of processing when detecting an incoming call, and FIG. The figure shows tie 11, channel 1, and so on, showing an example of the transmission procedure according to the model of FIG.

Claims (1)

[Claims] In a transmission control method for an ISDN terminal device that uses ISDN as a transmission path, a calling terminal sets information representing the transmission mode to be used in the user-to-user information element of a call setup message, and a destination terminal sets information in the received call setup message. When a user-user information element is included, the transmission mode information set in it is retrieved, and if the content of the transmission mode information can be used by the own terminal, a response message is sent immediately after the determination, and the transmission is performed. 1. A transmission control method for an ISDN terminal device, characterized in that if the content of mode information cannot be used by the own terminal, a response message is sent after a certain period of time has elapsed since the determination.