JP2804548B2 - Control method of data terminal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a data terminal device provided with hierarchical transmission control software for independently implementing transmission control processing of each of seven layers of an OSI reference model. Control method.

[Prior Art] For example, as a model of a protocol (transmission control procedure) of a data terminal device such as a group 4 facsimile device, an OSI (Open System Interconnection) of OS (International Organization for Standardization) The reference model is used as a standard model.

As shown in FIG. 8, this OSI reference model guarantees communication to an adjacent open system such as a physical layer (hereinafter, referred to as layer 1) for controlling a transmission medium and a relay node (relay station). Link layer (hereinafter, referred to as layer 2), a network layer (hereinafter, referred to as layer 3) for guaranteeing communication to an end-open system such as a data terminal, and a transformer for providing a transparent transmission path. Port layer (hereafter,
Layer 4), a session layer (hereinafter, layer 5) for performing conversation control, a presentation layer (hereinafter, layer 6) for unifying the information expression format, and for management and users of the entire system. And an application layer (hereinafter, referred to as a layer 7) for providing this protocol.

For example, in two terminals TEa and TEb connected via the transmission medium MD, a protocol between the same layers is defined (horizontality of the protocol) so that the communication function works well between the same layers. The interface between the layers is defined so that changing the protocol of a layer does not affect the protocol of another layer (protocol independence).

In a data terminal apparatus having a hierarchical protocol layer configuration conforming to such an OSI reference model, for example, a group 4 facsimile apparatus, transmission control software for processing a protocol of each layer is independently configured.

When transmitting image information data with such a group 4 facsimile apparatus, first, when the image information data is formed on the layer 7, it is temporarily stored in an image storage device or the like, and the layer 6 transmits the image information data. The image information data is cut out for each unit, the header information necessary for the processing of the layer 6 of the partner terminal is added, and the image information data is framed.

The layer 5 passes the transmission data to the layer 4 with the header information necessary for the processing of the layer 5 of the partner terminal added.

Hereinafter, when each of the layers 4, 3, and 2 receives transmission data from a higher layer, it adds protocol information necessary for processing by the same layer of the partner terminal, and in that state,
Pass the transmission data to the lower layer.

In this manner, the transmission data output from the layer 1 to the transmission medium MD is sequentially layered into communication data for one frame (in this case, image information data) as shown in FIG.
6,5,4,3,2 header information is added.

On the other hand, the terminal device receiving such transmission data,
Layers 2, 3, 4, 5, and 6 sequentially process the corresponding header information,
When it is necessary to pass the data to a higher layer, the transmission data from which the header information of the same layer is removed is passed to the upper layer.

Separately, at the stage before transmitting communication data,
Protocol processing for negotiating and adjusting functions to be used is performed between each layer in one terminal.

Transmission control data used for this protocol processing is:
At the transmitting terminal, the transmission control data is passed from the layer in which the transmission control data is generated to the next lower layer, and is sent out to the partner terminal via the transmission medium MD. Is removed and passed to the layer that receives the transmission control data.

Therefore, the transmission control data is transmitted to the transmission medium in a state where the header information of the layer below the transmission control data is added.

Conventionally, transmission data of a frame carrying image information data as described above and transmission data of a frame carrying transmission control data generated by each layer in accordance with the protocol processing are transmitted through the same path. Since the data is transmitted to the terminal, the data is conventionally processed in the same manner without discrimination.

That is, the size of the transmission data of the frame carrying the image information data becomes a maximum of 2053 octets (bytes), and it is necessary to hold the transmission data of a maximum of seven frames in order to perform the window processing.
A plurality of 14371-byte blocks were secured in the memory, and transmission data was processed in units of the blocks.

[Problems to be Solved by the Invention] However, such a data terminal device has conventionally caused the following inconveniences.

That is, for example, when a packet switching network is used as a transmission medium, an RR frame, which is transmission control data of Layer 2, has a size of only 4 octets, but uses a block of 2053 octets to process it. Therefore, there has been a problem that the memory use efficiency is poor.

An object of the present invention is to provide a control method of a data terminal device which can solve such inconvenience and improve the memory use efficiency.

[Means for Solving the Problems] According to the present invention, transmission control software that generates transmission data stores transmission data in a buffer set in a common memory area.
While processing the transmission data stored in the buffer, a local memory area is allocated to the transmission control software of each layer, and the transmission control software that generated the transmission control data stores the transmission control data in the local memory area. In addition, the transmission control data stored in the local memory area is transferred to the transmission control software of the next layer.

[Operation] Therefore, transmission data and transmission control data are handled differently, and blocks each having a size corresponding to the transmission data can be used. Therefore, transmission control data having a smaller data size can be efficiently stored, and memory use efficiency is improved. I do.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a facsimile apparatus according to one embodiment of the present invention. This facsimile machine is group 3
It has both a facsimile machine function and a group 4 facsimile machine function.

In FIG. 1, a control unit 1 performs an operation control process of the facsimile apparatus, a group 3 facsimile transmission procedure process,
It performs group 4 facsimile transmission procedure processing and call procedure processing of the upper layer. The system memory 2 stores a processing program executed by the control unit 1 and various data necessary for executing the processing program. In addition, it constitutes a work area of the control unit 1. The parameter memory 3 is for storing various information unique to the facsimile machine.
It is composed of a rewritable nonvolatile semiconductor memory device such as a battery-backed SRAM (static random access memory).

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

The scanner 6 is for reading a document image at the resolution set for the group 4 facsimile apparatus, and the plotter 7 is for recording and outputting the image at the resolution set for the group 4 facsimile apparatus.

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

The encoding / decoding unit 9 encodes and compresses the image signal by a predetermined encoding method and decodes the image information in the encoded and compressed state into the original image signal. The unit 10 is for converting the pixel densities of the images of the scanner 4 and the plotter 5 to each other when the pixel densities of the images that can be transmitted by the destination terminal device are different from each other.

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

The ISDN interface circuit 12 is for physically connecting to the ISDN, and the layer 1 signal control unit 13 includes a signal processing function of the ISDN layer 1 and a signal of a D channel (signal channel) and two B channels (signal channels). (Information channel) signal integration / separation function.

The D channel transmission control unit 14 uses the D channel to
The CODEC 15 is used to perform analog signal / digital data signal conversion processing for transmitting analog signals using the ISDN B channel. is there.

The B channel transmission control unit 16 is for performing layer 2, 3, 4, and 5 transmission control processing in group 4 facsimile transmission control processing using the ISDN B channel (information channel).

The group 3 facsimile modem 17 is for realizing the modem function of the group 3 facsimile, and is a low-speed modem function (V.21) for exchanging transmission procedure signals.
Modem) and a high-speed modem function (V.29 modem, V.27ter modem) for mainly exchanging image information.

The switch 18 is for switching and connecting the CODEC 15 to one of a group 3 facsimile modem 17, a handset 19 for talking, and a speaker 20 for outputting a ringing tone or the like.

Control unit 1, system memory 2, parameter memory 3,
Character generator 4, clock circuit 5, scanner 6,
Plotter 7, operation display unit 8, encoding / decoding unit 9, pixel density conversion unit 10, image storage device 11, D channel transmission control unit 1
4, a CODEC 15, a B-channel transmission control unit 16, a group 3 facsimile modem 17, and a switch 18 are connected to an internal bus 21. Is performed via A hook signal FS indicating a hook state of the handset 19 is applied to the CPU 1 via the internal bus 21.

Here, a call setup / call release procedure performed by the ISDN terminal such as the facsimile apparatus with the ISDN at the time of data transmission will be described.

That is, as shown in FIG. 2, the calling terminal first sets the terminal function to be used, and sends a call setup message SETUP specifying the destination terminal to the ISDN to request call setup with the destination terminal. The ISDN sends a call setup message SETUP in which the identification information (ISDN address) of the calling terminal and the terminal function are set to the designated destination terminal, and the call is originated. Also, I
The SDN sends a call setting acceptance message CALL_PROC for notifying the call setting status to the calling terminal.

Upon detecting an incoming call, the called terminal sends out a calling message ALERT to ISDN continuously at a predetermined interval when the own terminal is in a state where it can receive a call.
T is transmitted to the calling terminal to notify that calling of the called terminal has started.

When the called terminal answers the incoming call, the response message CONN is sent to ISDN.
ISDN sends a response message CONN to the calling terminal to notify that the called terminal has accepted the call.

Also, ISDN sends a response confirmation message CONN_ACK to the called terminal.
To confirm the response of the called terminal, at which point an information channel (B channel) for data transmission is established between the calling terminal and the called terminal.

Thus, data transmission using the information channel is performed between the calling terminal and the called terminal according to the transmission control procedure set for the transmission function of each terminal.

When the data transmission is completed, the originating terminal sends a disconnection message DISC to the ISDN to request release of the information channel, and the ISDN sends a disconnection message DISC to the destination terminal to notify the destination of the restoration of the information channel.

As a result, when the destination terminal responds to the ISDN with a release message REL for notifying the completion of the channel disconnection, the release message REL is transmitted from the ISDN to the calling terminal. When the channel release is completed, the calling terminal issues a release completion message REL_COMP to the ISDN.
To notify that fact, ISDN sends a release completion message REL_COMP to the destination terminal, the release of the information channel is established, and the information channel set between the calling terminal and the destination terminal Is completely released.

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

FIG. 3 shows an example of a transmission control procedure performed by the group 4 facsimile apparatus with a partner terminal during data transmission. This example shows a case where the number of transmitted originals is two using ISO8208 as the layer 3 protocol in the circuit switching mode.

First, the originating terminal sends a command SABME to activate the layer 2 of the destination terminal. When the destination terminal confirms the establishment of the layer 2 (adjustment of the procedure class), the destination terminal sets up the layer 3 end-to-end. , A signal SQ, and the receiving terminal responds with a signal SF when accepting it.

In this way, when Layer 3 is established, the calling terminal will:
A block TCR is sent to request a layer 4 connection, and the receiving terminal accepts the block TCR,
Respond A (adjust block size).

When the layer 4 is established, the calling terminal sends a command CSS to instruct the start of the layer 5, and the receiving terminal responds to the response RSSP (adjustment of the window size) when receiving the command CSS.

When the layer 5 is established, a command CDCL is sent to notify the terminal capability to be used in the layer 6 (document layer (= corresponding to the presentation layer)). Response RD
Respond CLP.

In this way, when the setting of the transmission function is completed, the calling terminal sends a command CDS to notify the start of sending the document, cuts out the sending data (image information data) in units of one block, and sends it to the frame CDUI. To send by.

When the transmission of the image information of the first page is completed, the calling terminal sends a command CDPB indicating the end of the page (that is, there is a succeeding page), and the destination terminal normally receives the image information of the first page. Responds with the response RDPBP.

When the transmission of the image information of the first page is completed, the calling terminal transmits the image information of the second page by the frame CDUI in the same manner as the image information of the first page, and transmits the image information of the second page. When the transmission is completed, a command CDE indicating the end of the document is transmitted. The receiving terminal returns a response RDEP when the image information of the second page is normally received.

In this way, when all the transmission of the image information is completed, the calling terminal sends a command CSE to notify the end of layer 5, and the called terminal, when accepting it, responds to the response RSEP.
To respond.

When layer 5 ends normally, the calling terminal sends a command CQ to end layer 3, and the called terminal responds with a response CF when accepting it.

When Layer 3 ends normally, the originating terminal sends a command DISC to end Layer 2, and the destination terminal responds with a response UA when accepting it.

In this manner, image information transmission on the B channel is performed.

In this embodiment, the transmission control processing at the time of image information transmission executed by the control unit 1 and the B-channel transmission control unit 16 is configured as shown in FIG.

That is, the tasks in charge of processing of each layer are configured independently, and resources such as a common area of a memory are managed by the operating system, and when requested by each task, resources are allocated to the task requested by the operating system. Like that.

However, exchange of transmission control data is performed between adjacent tasks.

In addition, as shown in FIG. 5, each task is mainly assigned to each task in a part of the work area formed in the system memory 2 so as to be independently usable for storing transmission control data and the like. Area LAR,
In addition, a common area CAR in which communication data commonly accessed by each task is stored is formed, and the common area CAR is treated as a resource by the operating system.

As shown in FIG. 6A, the common area CAR includes an area TMC for storing a common area management table for managing the common area CAR, and a plurality of areas having a size corresponding to the re-large capacity of the communication data. Area BDA.
The operating system assigns blocks of the area BDA to tasks.

The common area management table includes, as shown in FIG.
Stores table number information TID for identifying the common area management table, task identification information TSK for identifying a task to which the common area management table is assigned, and a start address of a block corresponding to the common area management table. It comprises head address information TAD, byte number information TBN for storing the size of valid data stored in the block, and a releasable flag FRL indicating whether the task can release the block.

With the above configuration, when transmitting the image information data, the layer 7 task operates the scanner 6 to read the image signal of the transmission original, and encodes and compresses the image signal by the encoding / decoding unit 9 to obtain the image signal. The stored image information is stored in the image storage device 11.

In this way, while the transmission image information is stored in the image storage device 11, the layer 6 task
The image information data stored in 11 is cut out in units of one block, a frame CDUI is formed using the layer 6 task area (area LAR), and a block allocation is requested to the operating system.

This allows the operating system to
One of the unused common area management tables (the contents of the task identification information is blank) is selected, and the table number information TID of the common area management table is stored.
Is notified to the layer 6 task.

The layer 6 task has table number information TID that matches the table number notified from the operating system.
Find the common area management table that has the ID information set for the invoking task in its task identification information TSK, and from the address stored in the head address information TAD of the common area management table, find the frame CDUI Data is stored sequentially, and the number of bytes of the frame CDUI is
Set in the byte number information TBN of the common area management table. At this time, the release enable flag FRL is set.

In this way, when the frame CDUI is stored in any block of the area BDA, the layer 6 task becomes the layer 5
Notify the task that there is data to send,
The table number information TID of the common area management table corresponding to the block storing the data of the frame CDUI is notified.

Accordingly, the layer 5 task obtains the head address of the block storing the data of the frame CDUI from the head address information TAD of the common area management table of the table number information TID notified from the layer 6 task, and obtains the address. Then, the data of the number of bytes stored in the byte number information TBN is read, header information is added to the read data, and the data is stored again in the same block. Also,
The layer 5 task stores information representing the task itself in the task identification information TSK of the common area management table, and stores the number of bytes of data stored in the block in the byte number information TBN.

In this way, when the header information is added, the layer 5
The task notifies the layer 4 task that there is transmission data and also notifies the table number information TID notified from the layer 6 task.

Thereafter, the lower task is sequentially notified of the table number information TID of the common area management table, and the header information is sequentially added to the frame CDUI to form transmission data (see FIG. 7).

This operation is repeated for each frame, and the image information data stored in the image storage device 11 is transmitted to the partner terminal.

The operation when transmitting the transmission control data will be described below.

First, each task forms a management table similar to the common area management table formed by the operating system in the common area CAR in the area LAR assigned to the invoking task, and, similarly to the area BDA, the transmission control data. Are formed in a plurality of blocks each having a capacity corresponding to the size. However, in this case, instead of the table number information, information of the start address (hereinafter, referred to as a table address) of the management table is set in the management table.

For example, when a layer 6 task forms a command CDCL, the command CDCL is stored in a free block of the area LAR allocated to the own task, and task identification information and byte number information are set in a management table corresponding to the block. Further, with the release enable flag reset, the layer 5 task is notified of the presence of transmission control data and the table address information of the management table.

Accordingly, the layer 5 task reads the management table with reference to the table address information notified from the layer 6 task, and transmits, from the address indicated by the start address information, the transmission control data of the byte number indicated by the number-of-byes information to the layer 6 task. The task is extracted from the area LAR allocated to the task, and header information is added to the extracted transmission control data. Next, the data is stored from the same head address, the number of bytes information is changed, the task identification information is changed, and the layer 4 task is notified of the presence of transmission control data, and the table address of the management table is changed. Notify information.

Thereafter, the transmission control data is sequentially notified to the lower layer tasks, and the table address information of the layer 6 task is notified, and the corresponding header information is added to each task to generate the transmission control data. The task is stored in the block of the area LAR allocated to the task and sent to the transmission medium MD.

In this way, the transmission control data is stored in the block of the storage area managed by the task that generated the transmission control data, and is accessed from the task in the lower layer, so that the area LAR is larger than the block in the common area CAR. The size of the block formed in each task area can be significantly reduced, and as a result, the memory utilization efficiency improves.

In the above-described embodiment, the present invention is applied to a group 4 facsimile apparatus using ISDN as a transmission line. However, the present invention can be similarly applied to other data terminal apparatuses.

The above-described storage management method is an example, and other methods can be used.

In the above-described embodiment, the layer 3 protocol in the circuit switching mode is set to ISO8 as the B channel protocol.
Although 208 is used, the present invention can be similarly applied to terminal devices using other protocols.

[Effects of the Invention] As described above, according to the present invention, the transmission control software that generates the transmission data stores the transmission data in a buffer set in the common memory area, and the transmission control software of each layer While processing transmission data stored in the buffer, a local memory area is allocated to transmission control software of each layer,
Since the transmission control software that generated the transmission control data stores the transmission control data in its local memory area and transfers the transmission control data stored in the local memory area to the next layer of transmission control software, Transmission data and transmission control data are handled differently, and blocks of a size corresponding to each can be used, so that transmission control data with a smaller data size can be efficiently stored, and the effect of improving memory use efficiency is obtained. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a group 4 facsimile apparatus according to one embodiment of the present invention, FIG. 2 is a time chart showing an example of a transmission procedure when ISDN is used for a transmission line, and FIG. 4 is a time chart showing an example of a procedure, FIG. 4 is a schematic diagram showing a configuration example of control software,
5 is a schematic diagram showing a configuration example of a work area of a system memory, FIG. 6A is a schematic diagram showing a configuration example of a common area, and FIG. 5B is a schematic diagram showing an example of a common area management table. 7, FIG. 7 is a schematic diagram showing an example of a method of forming communication data, FIG. 8 is a schematic diagram for explaining an OSI reference model,
FIG. 9 is a schematic diagram showing an example of the format of communication data. 1 ... control unit, 2 ... system memory, 16 ... B channel transmission control unit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H04L 29/00-29/12 H04N 1/00 102 H04N 1/32

Claims (1)

(57) [Claims] 1. A method for controlling a data terminal device comprising hierarchical transmission control software for independently realizing transmission control processing of each of seven layers of an OSI reference model, comprising: The transmission data is stored in the buffer set in the common memory area, and the transmission control software of each layer processes the transmission data stored in the buffer, while the transmission control software of each layer stores a local memory. The transmission control software that allocates the area and generates the transmission control data stores the transmission control data in its local memory area and transfers the transmission control data stored in the local memory area to the next layer of transmission control software. A method for controlling a data terminal device, comprising: