JPH04207261A - Transmission control method for isdn terminal equipment - Google Patents

Abstract

PURPOSE:To remarkably shorten communication time by setting the communication function of the present terminal at an incoming terminal based on communication function information from an outgoing terminal, and holding the negotiation of a communication function with an opposite terminal when performing a call setting procedure. CONSTITUTION:An ISDN incoming terminal receives a call setting message from an ISDN outgoing terminal. When information with respect to the communication function is set on the subaddress of the message. The incoming terminal sets the communication function of the present terminal based on an attached communication function. The negotiation of the communication function between the opposite terminal is performed while the call setting procedure is performed. Thereby, the communication time after establishment of a communication pass can be remarkably shortened.

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 ISDN as a transmission path.

[Prior Art] In general, ISDs such as Group 4 facsimile machines
In an ISDN terminal device that uses N as a transmission path, IS
After establishing a communication path for an information channel between the DN and the other party's terminal by executing a call setup procedure, a predetermined transmission procedure is executed using that communication path to perform various functions used when transmitting image information. We were negotiating.

As a result, among the ISDN terminal devices of the same type connected to the ISDN, the ISDN that has the same transmission function as the own terminal
Data transmission can be performed appropriately with a terminal device.

An example of the transmission procedure is shown in FIG.

First, the originating terminal sends a call setup message 5ETUP specifying the target facsimile device as the destination to the ISDN to request a call setup with the destination terminal, and the ISDN sends the call setup message 5ETUP to the specified destination terminal. and make a call.

When the destination terminal responds to the incoming call, it sends a response message C0NN to I
Send to SDN, ISDN responds with message C0NN
is sent to the calling terminal to notify that the called terminal has accepted the call, and also sends a call setting acceptance message CALL-PROC to the calling terminal to notify the call setting status.

In addition, ISDN sends a response confirmation message C0N to the destination terminal.
N ACK is sent and the response of the destination terminal is confirmed. At that point, an information channel (B channel) for data transmission is established between the originating terminal and the destination terminal. , begins the transmission procedure on the B channel.

First, the originating terminal sends a command SABM to request link layer configuration, and the destination terminal responds with a response UA, thereby configuring the link layer.

The originating terminal then passes the network layer end-to-end.
The terminating terminal sends a signal SQ to establish a call, the terminating terminal sends a signal SF to accept or accept it, then the originating terminal sends a signal CR to request a call, and the terminating terminal sends a signal SF to request a call. ,
The call is accepted in response to the signal CA, thereby establishing the network layer.

The originating terminal then sends a signal TCR to configure the transport layer, and the destination terminal sends a signal TCA to accept it, thereby configuring the transport layer.

Then, the originating terminal sends a session start command C8S to set up a session layer connection, and the terminating terminal sends a session start acknowledgment response R85P.
, thereby starting the session layer.

Next, the originating terminal sends a document capability list command CDCL to negotiate the transmission capabilities to be used, and the destination terminal also sends a document capability list acknowledgment response RDCLP. Following the start command CbS, a document user information command CDUI is sent to notify the destination terminal of information specifying the transmission function to be used, and when the transmission is finished, a document end command CDE is sent.

Further, a document reference number is added to the document start command CDS in order to distinguish the information to be transmitted.

When the destination terminal receives the document end command cDE, it sends a document end affirmative response RDEP.

In this way, when preparations for image information transmission are completed, the originating terminal transmits image information for one document using multiple document user information commands CDUI following the document start command CDS, and then ends the transmission. Then, a document end command CDE is sent to notify the end of one document's image information. In addition, the document start command CD
A document reference number is added to S to distinguish the document to be transmitted.

When the destination terminal receives the document end command CDE, it sends a document end affirmative response RDEP to acknowledge that the reception of the document has ended normally.

In this way, when image information transmission for one document is completed,
The originating terminal sends a session termination command C3E, and the destination terminal sends a session termination affirmative response R8EP to release the session layer connection.

Next, the originating terminal sends out a network layer signal CQ, and the destination terminal sends out a signal CF, thereby releasing the network layer.

The originating terminal then sends a link layer command DISC, and the destination terminal sends a response UA, thereby releasing the link layer.

In this way, when the link on the B channel is released, the originating terminal sends a disconnection message Disc to the ISDN to start the D channel release procedure, and the ISDN sends a disconnection message DIsc to the destination terminal. to notify the restoration of the information channel.

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.

is sent. When the originating terminal completes channel release,
Notify ISDN by sending REL COMP to release completion, thereby ISDNi;! Release completion 1 A message ')REL' COMP is sent to the destination terminal, thereby completing the call release.

In this way, image information is transmitted from the originating terminal to the terminating terminal.

Further, FIG. 6 shows an example of the transmission procedure when the transmission function cannot be normally negotiated.

In this case, when the destination terminal receives the document user information command CDUI that notifies the transmission function to be used from the originating terminal, it responds with a session cancellation command C8A,
The originating terminal notifies the interruption of the image information transmission procedure, and upon acceptance thereof, responds with a session termination affirmative response R8AP.

After this, lower layers are sequentially released under the initiative of the terminating terminal, and the call between the originating terminal and the terminating terminal is released.

[Problems to be Solved by the Invention] However, in such a conventional method, procedure signals of many layers are exchanged, which increases the time from when a call is connected until the actual transmission of image information begins. This caused an inconvenience.

Further, even if negotiations regarding the transmission function are not successful and image information is not transmitted, the previous transmission procedures are still exchanged, resulting in the inconvenience of wasted communication costs.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transmission control method for an ISDN terminal device that can reduce communication costs.

[Means for Solving the Problems] In the present invention, a calling terminal sets at least information regarding communication capabilities in the subaddress information element of a call setting message and makes a call, and a receiving terminal sends a call by setting at least information regarding communication capabilities in the subaddress information element of a call setting message. When at least information regarding the communication function is set in the subaddress information element, the communication function of the own terminal is set based on that information, and the communication function is negotiated with the other terminal during the call setup procedure. It is something.

[Operation] Therefore, since the transmission function is negotiated during the call setup procedure, the communication time after establishing the communication path can be significantly shortened.

[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 a group 3 facsimile function, a group 4 facsimile function, and a telephone call function.

In the figure, a control unit 1 executes operation control processing of the facsimile device, group 3 facsimile transmission procedure processing, group 4 facsimile transmission procedure processing of the upper layer, and call procedure processing, and memory 2 includes:
It stores the processing program executed by the control section 1 and various data necessary for executing the processing program, and constitutes the work area of the control section 1.

The scanner 3 is for reading the original image at the resolution set in the Group 4 facsimile device.
The plotter 4 records and outputs images at the resolution set in the group 4 facsimile device.

The operation display section 5 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 6 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. a7 is for storing various information such as a transmitted image signal, transmitted image information, received image information, and received image signal.

The PSTN communication control unit 8 is for transmitting image information with a group 3 facsimile device connected to the PSTN, and the ISDN communication control unit 9 is for transmitting image information with a group 4 facsimile device connected to the ISDN. It is used for transmission.

Control unit 1, memory 2, scanner 3, plotter 4, operation display unit 5, encoding/decoding unit 6, image storage device 7, PSTN
The transmission control unit 8, Oyohi, and ISDN transmission control unit are connected to an internal bus 10, and various information is exchanged between these elements mainly via this internal bus 10.

As shown in Figure 2 (a), each message for ISDN call setup is based on protocol specifications (format, sequence, etc.) that define layer 3 call control messages.
A protocol identifier to identify the message, a call number to identify which call the message is related to, a message type to identify the content of each message, and a mandatory message that is always added to each message. It consists of information elements and additional information elements added to each message as necessary. Note that 0, 1°, or a plurality of essential information elements are set depending on the message type, and 0.1° or a plurality of additional information elements are arranged depending on the situation.

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", "called party number", "terminating subaddress", " It has information elements such as "low layer compatibility" and "high layer compatibility J."

An overview of these information elements will be explained below.

The "transmission capability" information element indicates whether the content of the information to be transmitted is voice, unrestricted digital information, restricted digital information, or 3.1KH.
Information transfer capability that indicates whether it is z audio, 7KHz audio, or video, transfer mode that indicates whether the switching function used is circuit switching or packet switching, and information transfer speed. It consists of information on the speed, information transfer format, and information on the user information protocol.

The "calling number" information element contains the ISDN number of the calling terminal, and the "terminating number" information element contains the ISDN number of the called terminal. The "destination bus address J" information element is used to identify the target terminal among up to eight terminals connected to the same in-house wiring (passive bus) on the destination side.

The "lower layer compatibility" information element is used to check the possibility of communication with the other terminal, and its basic content is the same as the "transmission capability J information element. Furthermore, this "lower layer compatibility" The “gender” information element includes more detailed content.

The "higher layer compatibility" information element is used to check the compatibility with the partner terminal, for example, group 2
/Group 3 facsimile, Group 4 facsimile,
-Displays which terminal function is provided, such as mixed mode, teletex, videotex, telex, or message handling system.

In this embodiment, the "destination subaddress" information element is used to notify the destination terminal of the transmission function to be used when transmitting image information, and an example of the signal format is shown in FIG.

In this case, transmission function information indicating the transmission function to be used is set following subaddress information indicating the subaddress.

FIG. 3 shows an example of a transmission procedure when image information is transmitted by this facsimile apparatus with the above configuration.

First, the originating terminal sends a call setup message 5ETUP specifying the destination facsimile device as the destination and setting the above-mentioned transmission function information in the "destination subaddress" information element.
SDN to request call setup with the destination terminal, I'S
DN sends a call setup message 5E to the designated destination terminal.
Send TUP and make a call.

When the destination terminal receives the call setup message 5ETUP and detects the incoming call, if the call setup message 5ETtJP includes a "termination subaddress" information element, the destination terminal checks its contents and determines the function of the set transmission function information. Determine whether your own device can use it, and if it can,
Sends response message C0NN to ISDN.

As a result, ISDN sends a response message C0NN to the originating terminal to notify that the called terminal has accepted the call, and also sends a call setup acceptance message CALL PROC to the originating terminal to notify the call setup status. .

In addition, ISDN sends a response confirmation message C0N to the destination terminal.
W ACK is sent and the response of the destination terminal is confirmed. At that point, an information channel (B channel) for data transmission is established between the originating terminal and the destination terminal. starts the transmission procedure on the B channel.

First, the originating terminal sends a command SABM to request link layer configuration, and the destination terminal responds with a response UA, thereby configuring the link layer.

The originating terminal then passes the network layer end-to-end.
The terminating terminal sends a signal SQ to establish a call, the terminating terminal sends a signal SF to accept or accept it, then the originating terminal sends a signal CR to request a call, and the terminating terminal sends a signal SF to request a call. ,
The call is accepted in response to the signal CA, thereby establishing the network layer.

The originating terminal then sends a signal TCR to configure the transport layer, and the destination terminal sends a signal TCA to accept it, thereby configuring the transport layer.

Then, the originating terminal sends a session start command C8S to set up a session layer connection, and the terminating terminal sends a session start acknowledgment response R85P.
, thereby starting the session layer.

Next, the originating terminal sends a document capability list command CDCL to negotiate the transmission capabilities to be used, and the destination terminal also sends a document capability list acknowledgment response RDCLP, thereby adjusting the reception capabilities. will be held.

In this way, when preparations for image information transmission are completed, the originating terminal transmits image information for one document using multiple document user information commands CDUI following the document start command CDS, and then ends the transmission. Then, a document end command CDE is sent to notify the end of one document's image information. In addition, the document start command CD
A document reference number is added to S to distinguish the document to be transmitted.

When the destination terminal receives the document end command CDE, it sends a document end affirmative response RDEP to acknowledge that the reception of the document has ended normally.

In this way, when image information transmission for one document is completed,
The originating terminal sends a session termination command C8E, and the destination terminal sends a session termination affirmative response R3EP to release the session layer connection.

Next, the originating terminal sends out a network layer signal CQ, and the destination terminal sends out a signal CF, thereby releasing the network layer.

The originating terminal then sends a link layer command DISC, and the destination terminal sends a response UA, thereby releasing the link layer.

In this way, when the link on the B channel is released, the originating terminal sends a disconnect message Disc to the ISDN to initiate the release procedure of the D channel, and the ISDN:
A disconnection message DISC is sent 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 that the channel has been disconnected, the ISDN
A release message REL is sent from the originating terminal to the originating terminal. When the channel release is completed, the originating terminal sends a release completion message REL COMP to notify the ISDN, and the ISDN then sends a release completion message REL
COMP is sent to the terminating terminal, thereby completing the call release.

In this way, image information is transmitted from the originating terminal to the terminating terminal. In addition, since the image information transmission function is negotiated during the call setup procedure, the transmission procedure for negotiating image information transmission can be omitted from the transmission procedure on the B channel.
Communication time can be shortened.

In addition, when the destination terminal cannot use the specified transmission function, the call setup message 5ETU is sent as shown in FIG.
It responds to P with a disconnection message DISC. As a result, a call release procedure is started, so no image information is transmitted.

Therefore, if the transmission function negotiations fail, the procedure for image information transmission is aborted during the call setup procedure, an information channel is not established, and communication costs in such a case are not wasted. .

In the above embodiment, the transmission function is notified using the "destination subaddress" information element, but the transmission function can also be notified using the "originating subaddress" information element.

Further, in the embodiments described above, the present invention is applied to a facsimile machine, but the present invention can be similarly applied to other ISDN terminal devices.

[Effects of the Invention] As explained above, according to the present invention, the transmission function is negotiated during the call setup procedure, so the communication time after establishing the communication path can be significantly shortened. get.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a facsimile apparatus according to an embodiment of the present invention, FIG. 2(a) is a schematic diagram showing the signal format of a call setting message, and FIG. 2(b) is a schematic diagram showing the signal format of a call setting message. A schematic diagram showing an example of the format of the "1st subaddress" information element. Figure 3 shows an example of the transmission procedure when the device in Figure 1 transmits image information. A time chart, FIG. 4 is a time chart showing an example of a procedure when image information transmission is aborted because the destination terminal cannot use the specified transmission function, FIG. 5 is a time chart showing an example of a transmission procedure of a conventional device, FIG. 6 is a time chart showing another example of the transmission procedure of the conventional device.

Claims (1)

[Claims] In a transmission control method for an ISDN terminal device that uses ISDN as a transmission path, a calling terminal sets at least information regarding the communication function in the subaddress information element of a call setup message and makes a call, and a destination terminal transmits the received call setup message. When at least information regarding communication functions is set in the subaddress information element of Featured ISDN
Transmission control method for terminal equipment.