JPH0927805A - Method and device for data communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a data communication system transferring data to lots of users simultaneously for the host and user side simple installations via a general network. SOLUTION: In a data communication system, data are fed from the host to plural users via a network, (a): the host uses a data server 1 to give data to plural 1st network interfaces connected to the network, (b): when the user accesses reception of data to the host via a 2nd network interface device connecting to the network, a line is set up between the 2nd network interface device and any of the plural 1st networks, and (c): the user receives the data via the line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication method and an apparatus thereof, and more particularly, to a one-way data communication method and an apparatus thereof for multimedia communication.

[0002]

2. Description of the Related Art In data communication via a general network, bidirectional communication in which a host and a user handshake one to one is mainstream. Personal computer communication is an example of this, and data can be mutually transmitted and received via an existing network using a modem that supports these protocols. In particular, it is widely used for services in which a host supplies data to arbitrary users.

FIG. 17 is a block diagram for explaining a conventional data communication system by bidirectional communication. In FIG.
A host (server) via an existing network
Shows an example of performing a service of supplying the data C to an arbitrary user. In this example, user A and user B are communicating with each other through personal computer and data C on the host (server) side
Are being accessed. Two server devices capable of supplying data C are provided on the host side, and user A and user B respectively have a server device D and a server device E,
Establish bidirectional communication with a one-to-one handshake. In this case, only two users can access the data C at the same time.

[0004]

However, the above-mentioned conventional one-to-one handshake bidirectional communication system has the following problems. In the conventional method, a serious problem arises when an arbitrary host provides a distribution service for supplying a large amount of information to a large number of users, such as an electronic newspaper, via an existing telephone line.

For example, in newspapers, innumerable readers every day
Since they try to obtain the same information, it is expected that a large number of users will inevitably access one piece of software in an electronic newspaper that digitizes it. Therefore, one to one
In two-way communication with handshaking, the host side needs to prepare a huge number of lines and modems in order to support a large number of users.

In this case, the load on the host increases extremely as the number of lines increases. When responding to all access from hundreds or thousands of lines, the load on the host reaches hundreds or thousands of times that of one line, and the introduction of supercomputers or multiple computers (or multiple supercomputers) It is necessary to introduce distributed processing by computer). As described above, in the one-to-one handshake bidirectional communication system, the equipment cost on the host side becomes enormous as the number of lines increases.

A method of distributing data to a large number of users such as broadcasting on one line is also conceivable, but it is practically difficult because the structure of the existing network, especially the exchange, has to be changed. A distribution service that supplies a large amount of information to a large number of users, such as an electronic newspaper, requires a large number of lines and a large number of modems when using an existing telephone line. Also, make it possible to configure with only simple logic circuits. If these can be realized, the load on the host will be light and the load on the user can be reduced.

[0008] In view of the above problems, an object of the present invention is to provide
Provided is a data communication system capable of simultaneously transferring data to a large number of users in a simple facility on a host side and a user side via a general network. Another object of the present invention is to provide a simple device for providing the data communication system of the present invention.

[0009]

Means for Solving the Problems To solve the above problems, the present invention is characterized by taking the following means. According to the first aspect of the present invention, there is provided a data communication system for supplying data from a host to a plurality of users via a network, wherein (a) the host stores data by a data server into a plurality of users. Supplying in parallel to a first network interface device, and (b) the user via a second network interface device connected to the network,
When accessing the supply of the data to the host,
Any one of the second network interface device and the plurality of first network interface devices
Establishing a line between the user and (c) the user receiving the data through the line.

In the invention according to claim 2, the step (a)
The method further includes the step (a-1) in which the data server repeatedly sends the data. In the invention according to claim 5, the step (a) further includes a step (a-2) of adding a unique word indicating a predetermined position of data in the data, and the step (c) includes the unique word. The invention according to claim 6, further comprising a step (c-1) of waiting until a word is detected and receiving data up to the next unique word after the word is detected. It is characterized in that it is a header indicating the position of the head.

In the invention according to claim 7, the step (a)
Further comprises the step of converting the data to which the header is added into a plurality of data outputs having stepwise different delay times, and the step (b) includes: when the user accesses the host, The method may further include connecting a line from the user to a data output with the shortest time until the header arrives.

[0012] In the invention according to claim 8, the step (a)
Further comprises generating a plurality of data outputs in which the data to which the header is added is repeated stepwise at different timings, and in the step (b), when the user accesses the host, The method may further include connecting a line from the user to a data output with the shortest time until the header arrives.

In the invention according to claim 9, the step (a)
The method further comprises the step of dividing the data into a plurality of sub-data and adding different unique words to each other. The step (c) includes detecting one of the unique words and ending with the next unique word. The method may further include receiving (c-2) all sub data, and (c-3) reproducing the data from the received sub data based on the unique word.

According to the tenth aspect of the invention, the step (a) further includes a step (a-3) of adding an error correction code in the data, and the step (c) includes the error correction code. Correcting the error using (c-4)
Is further included.

In the twelfth aspect of the present invention, the data of the data server is the content of a newspaper article, and in the step (b), the host is automatically supplied with the data at a certain time every day. The step (c) may further include the step of disconnecting the line after receiving the data.

According to a thirteenth aspect of the present invention, there is provided a data communication device for supplying data to a plurality of users via a network, the data server transmitting the data to be supplied to the user, and the data server. A plurality of network interface devices that are connected to each other, establish a line with each of the plurality of users in response to an access from the plurality of users, and supply the data to the plurality of users, respectively. To do.

According to a twenty-second aspect of the present invention, there is provided a data communication device for receiving data from a host via a network, wherein the data communication device is connected to the network, accesses the host, and is installed in the host. A network interface device for establishing a line and receiving the data, and a terminal device for processing the data received by the second network interface device. And

A data communication system according to any one of claims 1 to 4, a data communication device according to any one of claims 13, 14, and 15, and a data communication device according to claim 2.
In the data communication device according to any one of 2, 23, and 24, the server on the host side does not need to contact the user on a one-to-one basis. Therefore, the host can handle one-to-many even if there are many lines. That is,
When a large number of users are expected to be accessed, only one data server can be used by preparing the number of lines expected to be accessed at the same time and the corresponding modem.
Therefore, in conventional two-way communication such as personal computer communication, the capacity of the host computer had to be increased (sometimes, a supercomputer was necessary) with the increase in the number of lines on the host side. The communication method does not require a super computer or the like, and a small-scale facility can construct a system that delivers a large amount of data to many users at the same time.

A data communication system according to any one of claims 5 to 9, a data communication device according to any one of claims 16 to 19, and a claim 25 or 2
In the data communication device described in 6, the data is received based on the unique word in the data. Therefore, it is possible to receive the data in an orderly manner and reproduce the correct data. Further, in claims 7 to 9, it is possible to shorten the time until the unique word that is the reference of data reception is detected, and it is possible to start data reception in a short time.

In the data communication system according to claim 10 and the data communication device according to claims 20 and 27, an error correction code is added to the data, and the error is corrected on the receiving side based on the error correction code. . Therefore, errors in the received data are reduced. In the data communication system according to claim 11, ISDN is used as a network. Therefore, while transmitting a large amount of data,
Since the control channel and the data transmission channel can be handled independently, the device design can be facilitated.

In the data communication system according to the twelfth aspect and the data communication apparatus according to the twenty-eighth aspect, the contents of the newspaper article output from one data server are passed through a plurality of interface devices every day at a fixed time. To be transmitted to the user. Therefore, a user can easily access a large amount of newspaper data with a simple device.

In the data communication device according to the twenty-first aspect, when there is no access from the user, the data supply from the data server is stopped. Therefore, the data server does not uselessly supply the data, and the power consumption of the data server can be reduced.

In the data communication device according to the twenty-ninth aspect, it is easy to attach / detach the portable terminal body to / from the stationary adapter. Therefore, if the stationary adapter is connected in advance to the necessary line, the mobile terminal body can be freely moved and easily connected to the line, and data can be promptly received from the host.

[0024]

FIG. 1 is a block diagram for explaining a data communication system according to the present invention. As a general network, ISD serviced by NTT
A case where the N INS-NET64 network (circuit switching, bearer service) is used will be described. In addition,
The present invention can be realized not only in ISDN but also in various networks such as the current analog public network and packet network.

In FIG. 1, a host for supplying data, such as an electronic newspaper, is shown connected to a large number of users via ISDN. The equipment on the host side includes a data server 1 having a digital data repeat mechanism capable of repeatedly transmitting data, and n modems 2-1 to 2-.
n (hereinafter, each modem will be referred to as “modem 2”). The data repeatedly sent from the data server 1 is unilaterally supplied to the n modems 2-1 to 2-n. In addition, each modem is a line termination device (DSN) of ISDN.
U) to ISDN. The modem in this case supports the interfaces from layer 1 to layer 3 of the INS net 64.

The equipment on the user side includes modems 3-1 to 3-i (hereinafter, each modem is referred to as "modem 3") for establishing a line with the host, and a terminal for receiving data from the host. 4-1 to 4-i (hereinafter, each terminal is referred to as “terminal 4”). The same modem 3 as the modem 2 on the host side can be used. The modems 3 can also be incorporated in the terminals 4, respectively. Each user is connected to the ISDN via the DSU. DS
U is generally installed in the house by a telecommunications carrier.

Before describing the operation of the data communication system of FIG. 1, the operation of the ISDN modem 2 and modem 3 will be described. FIG. 2 is a diagram for explaining the operation of the ISDN modem. In ISDN, a B channel (data channel) that carries data and a D channel (control channel) that performs a calling sequence of the line itself (call control) are independent. In each modem, the B channel and the D channel are separated, the B channel of the modem 2 is connected to the data server 1, and the B channel of the modem 3 is connected to the data receiving unit (not shown) of the terminal 4.

The D channel of the modem 2 is connected to the local microcomputer 5 in the modem, and the D channel of the modem 3 is connected to the local microcomputer 6 in the modem to establish a line between them. A calling sequence is performed. The handshaking processing of the calling sequence by the D channel (LAPD) can be almost self-contained by the ISDN modem (configurable by the processor), so that the B channel can substantially handle only the data.

In the data communication system of the present invention, since the data on the host side is transmitted to each user in only one direction, substantially only the B channel in one direction (host → user) is used. That is, only the B channel for line connection is used, and the LAPB of the B channel package is not used. Therefore,
The B channel on the host side is dedicated to transmission, and the B channel on the user side is dedicated to reception.

Next, detailed operation of the data communication system of the present invention will be described. On the host side, as shown in FIG. 1, the data output from the data server 1 having the digital data repeat mechanism is transmitted to a plurality of modems 3 (ISDN).
Processor) B channel data input in parallel. The ISDN processor is connected to each access line and waits for an access from a user. As shown in FIG. 1, the overall configuration of the host is such that one data server supports ISDN via a plurality of modems and one-to-many data distribution is possible.

On the other hand, when the user accesses the host to supply data, the first line establishing operation (calling sequence) is performed between the modem 3 and the modem 2 through the D channel in a one-to-one manner. Done in. After the line is established, the data server 1
The data constantly transmitted from the device is transferred by being loaded on the unidirectional B channel via the modem. In this case, there is essentially no data flow from the user to the host. The B channel for data is not bidirectional communication but unidirectional communication from the host to the user, and does not use B channel packets. In the above operation, the calling sequence on the host side is self-processed in the modem, so that the host computer itself is not directly accessed by the user. Also, as many as the number of prepared modems,
Multiple users can access it at one time.

By the above operation, the server on the host side does not have to contact the user on a one-to-one basis, and even if there are many lines, one-to-many correspondence is possible. The server does not have to interact (handshake) with many users at the same time. That is, when a large number of users are expected to be accessed, a single data server is sufficient if the number of lines expected to be accessed at the same time and the corresponding modems are prepared. Also, the modem is a 1-chip IC
It is easy to implement, and large facilities are not required even if the number of lines increases. Therefore, in conventional two-way communication such as personal computer communication, the capacity of the host computer had to be increased (sometimes, a supercomputer was necessary) with the increase in the number of lines on the host side. The communication method does not require a super computer,
With a small-scale facility, it is possible to build a system that delivers a large amount of data to many users at the same time.

The data server 1 having the digital data repeat mechanism shown in FIG. 2 can be easily constructed by mounting an expansion board on a personal computer. Further, it can be configured by a logic circuit. FIG. 3 shows a configuration example of a digital server using a logic circuit. In this configuration example, data is recorded in the semiconductor memory and the address is repeated by the repeat counter. If the contents of the semiconductor memory are rewritten or a plurality of banks are prepared and different data are recorded, one server can supply various data. Since these can be configured with only logic circuits, a personal computer is not required and the equipment is extremely simple. In addition, the digital data repeat mechanism can be configured by using a tape streamer or the like.

However, in the data server shown above, the data is constantly reproduced repeatedly regardless of the start time of the access from the user, and the data at the moment of access becomes chaotic for the user. FIG. 4 is a diagram showing a format of data supplied from the data server. A specific bit pattern representing a header (head position of data) is added to the data supplied from the data server 1, and then repeat reproduction is performed. The host side is
Since the data is unilaterally repeatedly reproduced, the reproduction position of the data cannot be specified at the moment of starting the access.
However, since the data is being replayed repeatedly, the header always appears after waiting for a while. Therefore, the user can recognize the beginning of the data by waiting until the header is detected, and by capturing the data after that,
Can receive orderly data. At this time, if automatic recording is performed, the header is detected and data is recorded, and the line is disconnected when the next header or footer (data end code) is detected. This makes it possible to prevent the same data from being recorded again.

The header may have any format as long as it is a bit pattern that does not exist in the data body. It should be noted that the power consumption of the data server can be reduced by stopping the repeat reproduction of the data when the data is not accessed at all and reproducing the data only when the access occurs.

Further, in the data supplied by the data server,
An error correction code can be added. In the one-way data communication system of the present invention, even if an error can be detected as in the two-way communication system, a frame retransmission request cannot be made. When an error is detected, there is a means to read the same data again, but since repeat reproduction is performed, it is necessary to wait until the header, which increases the communication time. By adding the error correction code, it is possible to reduce the generated error.

FIG. 5 is a diagram showing an example of a protocol of the data communication system of the present invention including error correction. The error correction method is not limited to that shown in this figure. In FIG. 5, 2B of the INS net 64 is used for data distribution, and a 16-bit bus width is secured in the parallel state.

On the host side, the word data input is first converted into byte data of every 8 bits, and a Hamming error correction code of 6 bits (BCH 7.4) is added. To this, 1 bit for header identification signal and 1 bit for byte / word conversion signal (corresponding to BHE / A0) are added,
It becomes a bit parallel signal. The header identifying signal is an identifying signal for indicating whether the data is data of an electronic newspaper or the like or the header described in FIG. This parallel signal is converted into a serial signal. The above signal assembly can be performed outside the data server 1 or inside thereof. The serial signal is transmitted to the user via the ISDN 2B channel in the ISDN interface modem.

At the terminal on the user side, after 2B of ISDN is converted into parallel, an error syndrome is created from the Hamming code and error correction processing is performed. Then, using the byte / word conversion signal, 8-bit byte data is converted to 1
Convert to 6-bit word data. The above processing can be performed by the modem on the user side. Since the above word data is valid from the header identification signal to the next header identification signal, the interval is detected, processed, recorded,
Playback etc.

In the above data communication system, a header is added to the data supplied from the data server, and the user waits for the header to receive the data. However, when the information amount of software is large like video-on-demand, the waiting time to the header becomes too long, which is inconvenient. A data communication method for coping with such a case will be described below.

FIG. 6 is a block diagram for explaining the second embodiment of the data communication system of the present invention. In the data communication system shown in FIG. 6, a delay circuit using a FIFO memory or the like is connected to the output of the data server to convert it into a plurality of data outputs having several kinds of delay times. These are connected to a plurality of transmission-only modems via a matrix switch. Then, when the access from the user occurs, the line from the user is connected to the output that is the shortest in time until the header arrives.

FIG. 7 is a modification of the second embodiment of the data communication system of the present invention shown in FIG. In the second embodiment shown in FIG. 6, the matrix switch is placed between the plurality of data outputs and the plurality of transmission-only modems. But PB
When the line is distributed to the transmission-dedicated modems via X, as shown in the example of FIG.
It is possible to install a matrix switch between it and the BX. Also in this case, the line from the user is connected to the output that is the shortest in time until the header arrives.

FIG. 8 is a block diagram for explaining the third embodiment of the data communication system of the present invention. In the data communication system shown in FIG. 8, a plurality of data servers (or data reproducing devices such as tape streamers) are prepared and data is transmitted with a time lag. In this case as well, as in the previous example, when an access from a user occurs, the line from the user is connected to the output that is the shortest in time until the header arrives.

FIG. 9 is a modification of the third embodiment of the data communication system of the present invention shown in FIG. Also in the third embodiment shown in FIG. 8, in the same way as in FIG. 7, when the lines are distributed to the transmission-dedicated modems via the PBX, a matrix switch may be installed between the PBX and a plurality of transmission-dedicated modems. it can. The operation is the same as in FIG.

In the embodiments of FIGS. 7 and 9, it is obvious that the matrix switch can be installed between a plurality of data outputs and a plurality of transmission dedicated modems.
The following method is also available as a method of shortening the waiting time to the header. On the host side, the data of the data server is subdivided into packets, and each packet is given a serial number as a header, for example. When the user accesses the data, the data is fetched from the packet data of the serial number N immediately after the access. Then, the recording of the data is completed with the serial number (N-1).

The data is rearranged in the order of serial numbers at the user side terminal, the packet header is removed, and the data is restored. This method can significantly reduce the average time required to wait for a header. The serial number may be any numerical value (for example, a random numerical value or some code) as long as the restoration order is determined between the host and the user.

Further, FIG. 5 in the above-mentioned data communication system
The data generation protocol indicated by can be easily emulated by software on a computer such as a personal computer. Alternatively, the hardware may be configured by an IC. In this case, an IC including the modem shown in FIG. 2 is possible.

FIG. 10 shows a block diagram of a one-way data communication system modem. The transmission-only modem on the host side is provided with a header / footer addition circuit and an error correction parity addition circuit in addition to the ISDN processor and LOCAL-MPU. The header / footer addition circuit is
For example, it can be configured by a multiplexer and can be added by switching between data and header code. In addition, the receive-only modem on the user side is an ISDN processor and a LOCAL-
In addition to the MPU, a header / footer detection circuit and an error correction circuit are provided. The header detection circuit serves as a trigger for starting recording by DMA transfer. The parity addition circuit and the error correction circuit can be configured by a wired logic. Also, the header / footer addition / detection circuit, the parity addition circuit, and the error correction circuit can be emulated by software. Further, the header can be incorporated into the data from the beginning. However, during communication, since it is real-time processing,
If high speed is required, hardware implementation is more effective. The data line in the ISDN processor is dedicated for transmission on the host side and dedicated for reception on the user side, and constitutes a one-way communication data line.

The handshake for the calling sequence is self-processed inside the modem. Then, after entering the data transmission / reception process, the unidirectional data line is enabled. Therefore, the ISDN processor is provided with a state buffer or switch circuit (not shown) for enabling the unidirectional data line. The calling sequence is processed in the LOCAL-MPU as a local microcomputer.

Next, the overall configuration of the data communication system of the present invention will be described. FIG. 11 is a diagram showing a device configuration of the data communication system of the present invention. The host-side and user-side modems are combined with an optical or magnetic disk or a data recording medium such as a memory card.
Further, the data recording medium on the host side has a function of repeatedly reproducing the transmission data of the data recording medium, and the data recording medium on the user side has a function of recording data by using the header detection signal as a trigger. ing. Furthermore, if the amount of data to be sent and received is not so large, configure a cache memory on the data line with the modem,
Repeated reproduction of data and temporary recording of data can be performed on this cache memory.

FIG. 12 is a block diagram of a modem chip set having a cache memory. In this chipset,
The functions of both the host side and the user side are integrated to form a one-way communication processor. This processor is provided with a cache memory for repeating data on the host side and a cache memory for temporarily recording data on the user side. FIG. 12 shows L
Although a set of an ISDN processor chip including an OCAL-MPU and a two-way communication processor chip is shown, these can be configured by one chip or several chips. The present invention can be realized on a general computer by converting these chipsets into expansion boards or expansion cards for computers.

Regarding the data recording medium having the apparatus configuration shown in FIG. 11, the data repeat function and the automatic recording function (using the header as a recording start trigger) are programmed by utilizing a hard disk or a silicon disk of the computer main body. It is also possible to provide.

Next, the portable terminal used by the user will be described. When users access host data, they need to be able to access it anytime, anywhere, not just from a fixed location. Also, the present invention
It is suitable for electronic newspapers and the like, and since newspapers can be read virtually anywhere, it is necessary to configure the above-mentioned user-side device so that it is convenient to carry. FIG.
Shows an example of the configuration of a mobile terminal with an electronic newspaper function. This mobile terminal includes the user-side device shown in FIG. 11 or FIG.
Computer system body (CPU, DSP, memory,
It is integrated with the circuit by the system chipset etc.) and the panel display. Further, in the case of configuring as a mobile terminal having an electronic newspaper function (details will be described later), an autopilot program for automatically accessing to and downloading from a host by a timer is added.

This communication device is not limited to the case of accessing a host from a fixed line, but it can be carried out by holding a terminal.
For example, there is a case where a host is accessed from a wireless line and an electronic newspaper is read on a train. That is, in order to obtain the function of the electronic newspaper, it is necessary to achieve both portability and deferability of connection to the telephone line. Also, when using by connecting to a mobile terminal at daytime and connecting to a full-scale AV system at night, it is necessary to connect a cable to the AV system every time.

FIG. 14 shows a configuration example of a portable terminal having a stationary adapter. This example is composed of a stationary adapter (stand) and a mobile terminal body. The stationary adapter has a connector (contact) for electrically coupling the mobile terminal body to an external network, and the mobile terminal body can interface with the external network via the stationary adapter. it can.

The electrical connection is made by placing the portable terminal main body on the stationary adapter, similar to the relationship between the handset and the stand of the cordless phone. Then, the timer automatic reception function (auto pilot) of the electronic newspaper is activated when the mobile terminal body is set in the stationary adapter. Specifically, the connection between the two is detected, and an electric signal is input from the I / O port of the terminal, or the program activation of the timer automatic reception function (autopilot) is determined by the state of this port. At this time, the terminal body can also be charged.

Next, an application example of the above data communication system will be described. First, the data communication system of the present invention can be applied to an electronic newspaper service. For example, the host side inputs the newspaper data into the data server. On the user side, every morning in the early morning, a terminal (or a personal computer) may be automatically started by a timer to automatically access the host. The terminal detects the header of the data and automatically records the next header up to the built-in hard disk. When the user wakes up, he can hit the key on his terminal to read the electronic newspaper without waiting.

There are morning newspapers and evening newspapers, but in the case of electronic newspapers, the time required for printing is unnecessary, so the latest data can always be input to the data server. Unlike the general newspapers, the user can always know the latest information for an article having a quick-moving property such as news on TV, if the data is updated every hour, unlike ordinary newspapers.

FIG. 15 shows an IC for data communication system of the present invention.
FIG. This IC is useful as an IC used in the above-mentioned electronic newspaper service device. Each function will be described below. [Local Bus] A local bus completely independent from the bus managed by the CPU and a logic for controlling this are built-in. The local bus has a terminal outside the IC, and a local bus device can be connected to the outside. The IC performs generation of addresses and command strobes on the local bus, control of the local data bus, and the like. On the local bus, the main purpose is to transfer the communication data of the present invention to the data recording medium. [Local Bus Device] The communication bus architecture of the present invention and a cache memory are built in the local bus, and a silicon disk (data recording medium using a flash memory) is connected to the outside. In the first place, this IC is premised on efficient data transfer between the communication method architecture of the present invention and the cache memory on the local bus. [DMA] Access to the local bus device is basically performed by DMA. DMA can be used in combination with control logic to perform burst transfer (same as normal DMA use), repeat playback of specific address space (can be used for digital data repeat playback on host side / can also be used for video window repeat play). , It provides special functions such as external start & stop pulse control (on the user side, the header can be used to start recording and the footer can be used to stop recording). [Control logic and register group, comparator]
The operation is performed by an instruction (command operation to the register) from the upper CPU. Registers include start, stop, and hold. Basically, the transfer from the address value stored in the start register to the address value stored in the stop register is subject to transfer. The value of the start register is loaded into the counter at the beginning of the data transfer.

For burst transfer, writing or reading is performed from the local bus device to the silicon disk of this address. In the case of repeat reproduction, this address section is repeatedly reproduced until there is a command from the upper CPU. Further, the value of the stop register and the address value indicated by the counter (for example, binary up counter) are compared by the comparator, and if the counter address value is equal to or larger than the stop register value, the address count is stopped or the repeat count is repeated. Playback (loading the start register value to the counter and restarting counting) is executed. One-way data communication method,
When data is downloaded, the count start trigger and count stop trigger of the control logic (PLA) are connected to the header and footer detection signals of the present invention to start and end the DMA transfer. When the access is successful by this communication method, B channel data appears on the local data bus, so the header is detected and the data is written to the cache memory. Writing is performed by DMA from the address value indicated by the start register, and is stopped as soon as a footer is detected in the B channel. Therefore, in this case, the stop register is not used. [Circuit for One-Way Data Communication Method] As the architecture of the one-way data communication method of the present invention, a header addition circuit and an error correction code addition circuit are provided on the transmission-only modem side.
Header detection circuit (record start trigger) in the receive-only modem,
It has a built-in footer detection circuit (recording end trigger) and error correction circuit. On the user side, the header / footer detection signal controls the start-stop of the DMA transfer.

This IC has no built-in processing of ISDN layers 1 to 3, and the external ISDN processor can perform B processing.
Input / output channel serial data. Therefore, it has a built-in serial / parallel conversion circuit. [Direct Access Buffer] A direct access buffer is provided so that the upper CPU can directly operate the local bus. When the buffer is active, counter address output is disabled and the CPU can directly access devices on the local bus.

When the above IC is used to receive data such as an electronic newspaper, the following process is automatically started by a timer every morning. (1) The ISDN layers 1 to 3 processes are initialized so that they are on the verge of calling. (2) Write the recording start address of DMA in the start register. The DMA clock selector (DMA channel) and the local bus master device (read device) are set in the communication processor, and the local bus slave device (write device) is set in the cache memory device. (3) By setting the DMA mode for the data communication method of the present invention (connecting the header detection signal to the DMA start trigger to control the activation of the DMA), the reception waits. (4) Call the host. (5) The line is connected. (6) Data is input from the B channel, and when the first header is detected, DMA is used and recording in the cache memory is started. Stop recording in the footer and reset the system (default state). (7) Data is transferred from the cache memory to the silicon disk. Also in this case, DMA is used.

Next, the data communication system of the present invention can be applied to video on demand. FIG. 16 is a diagram showing an example in which the data communication system of the present invention is applied to video on demand. The video-on-demand is a service in which a host has a plurality of video software and a user can selectively receive arbitrary video software. In FIG. 16, lines are classified by software, and a correspondence table of line numbers and software names is received by the autopilot program about once a month. When the user specifies the software name, the terminal automatically accesses the line corresponding to the software. According to the data communication method of the present invention, the host side circulates each line until one succeeds in accessing a line that is not in communication because one line has a plurality of lines with one software.

[0064]

As described above, the present invention has the following effects. A data communication system according to any one of claims 1 to 4, a data communication device according to any one of claims 13, 14, and 15, and any one of claims 22, 23, and 24. In the data communication device described in the item 1, the server on the host side does not need to contact the user one to one. Therefore, the host can handle one-to-many even if there are many lines. That is, when a large number of users are expected to be accessed, a single data server is sufficient if the number of lines expected to be accessed at the same time and the corresponding modems are prepared. Therefore, in conventional two-way communication such as personal computer communication, the capacity of the host computer had to be increased (sometimes, a supercomputer was necessary) with the increase in the number of lines on the host side. The communication method does not require a super computer or the like, and a small-scale facility can construct a system that delivers a large amount of data to many users at the same time.

A data communication system according to any one of claims 5 to 9, a data communication device according to any one of claims 16 to 19, and a claim 25 or 2
In the data communication device described in 6, the data is received based on the unique word in the data. Therefore, it is possible to receive the data in an orderly manner and reproduce the correct data. Further, in claims 7 to 9, it is possible to shorten the time until the unique word that is the reference of data reception is detected, and it is possible to start data reception in a short time.

In the data communication system according to claim 10 and the data communication device according to claims 20 and 27, an error correction code is added to the data, and the error is corrected on the receiving side based on the error correction code. . Therefore, errors in the received data are reduced. In the data communication system according to claim 11, ISDN is used as a network. Therefore, while transmitting a large amount of data,
Since the control channel and the data transmission channel can be handled independently, the device design can be facilitated.

In the data communication system according to the twelfth aspect and the data communication apparatus according to the twenty-eighth aspect, the contents of the newspaper article output from one data server are transmitted at a predetermined time every day via a plurality of interface devices. To be transmitted to the user. Therefore, a user can easily access a large amount of newspaper data with a simple device.

In the data communication apparatus according to the twenty-first aspect, when there is no access from the user, the data supply from the data server is stopped. Therefore, the data server does not uselessly supply the data, and the power consumption of the data server can be reduced.

In the data communication device according to the twenty-ninth aspect, it is easy to attach / detach the portable terminal body to / from the stationary adapter. Therefore, if the stationary adapter is connected in advance to the necessary line, the mobile terminal body can be freely moved and easily connected to the line, and data can be promptly received from the host.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining a data communication system according to the present invention.

FIG. 2 is a diagram for explaining the operation of an ISDN modem.

FIG. 3 is a configuration example of a digital server using a logic circuit.

FIG. 4 is a diagram showing a format of data supplied from a data server.

FIG. 5 is a diagram showing an example of a protocol of a data communication system of the present invention including error correction.

FIG. 6 is a block diagram for explaining a second embodiment of the data communication system of the present invention.

FIG. 7 is a modification of the second embodiment of the data communication system of the present invention shown in FIG.

FIG. 8 is a block diagram for explaining a third embodiment of the data communication system of the present invention.

FIG. 9 is a modification of the third embodiment of the data communication system of the present invention shown in FIG.

FIG. 10 is a block configuration diagram of a one-way data communication system modem.

FIG. 11 is a diagram showing a device configuration of a data communication system of the present invention.

FIG. 12 is a configuration diagram of a modem chip set having a cache memory.

FIG. 13 is a configuration example of a mobile terminal with an electronic newspaper function.

FIG. 14 is a configuration example of a mobile terminal having a stationary adapter.

FIG. 15 is a configuration diagram of an IC for a data communication system of the present invention.

FIG. 16 is a diagram showing an example in which the data communication system of the present invention is applied to video on demand.

FIG. 17 is a configuration diagram for explaining a conventional data communication system by bidirectional communication.

[Explanation of symbols]

 1 data server 2, 2-1 to 2-n modem 3, 3-1 to 3-i modem 4, 4-1 to 4-i user terminal 5 host side local microcomputer 6 user side local microcomputer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04M 11/08 9466-5K H04L 11/02 Z

Claims (29)

[Claims] 1. A data communication system for supplying data from a host to a plurality of users via a network, wherein: (a) the host sends data by a data server;
Supplying in parallel to a plurality of first network interface devices connected to the network, (b) the user transmitting the data to the host via a second network interface device connected to the network. The second network interface device and the plurality of first devices when accessing the supply.
A network is established with any one of the network interface devices, and (c) the user receives the data through the line. 2. The method of claim 1, wherein step (a) further comprises the step of the data server repeatedly sending the data (a-1). 3. The method of claim 1, wherein step (c) does not include the step of transmitting the user's data from the user to the host. 4. The establishment of the line in step (b) is performed by a handshake between the second network interface device and any one of the plurality of first network interface devices, The method according to claim 1, wherein the method is performed independently of the data server. 5. The step (a) further includes a step (a-2) of adding a unique word indicating a predetermined position of data in the data, and the step (c) detects the unique word. 3. The method as claimed in claim 2, further comprising the step of waiting until the data is received and receiving the data up to the next unique word after detection (c-1). 6. The unique word is a header indicating the position of the beginning of the data.
The method described. 7. The step (a) further includes converting the data to which the header is added into a plurality of data outputs having stepwise different delay times, and the step (b) includes the step (a). 7. The method of claim 6, further comprising connecting a line from the user to a data output having the shortest time until the header arrives when the user accesses the host. 8. The step (a) further includes the step of generating a plurality of data outputs in which the header-added data is repeated in stepwise different timings, and the step (b) includes the step of: 7. The method of claim 6, further comprising connecting a line from the user to a data output having the shortest time until the header arrives when the user accesses the host. 9. The step (a) further includes a step of dividing the data into a plurality of sub-data and adding different unique words to each other, and the step (c) detects one of the unique words. And then receiving all sub-data up to the next same unique word (c-2),
The method of claim 2, further comprising reproducing the data from the received sub-data based on the unique word (c-3). 10. The step (a) further includes the step (a-3) of adding an error correction code in the data,
The method of claim 1, wherein the step (c) further comprises a step (c-4) of correcting an error using the error correction code. 11. The network is an ISDN, and the first network interface device and the second network interface device are ISDN.
Interface modem, and the step (b) is
2. The step of establishing the line via a SDN D channel, the step (c) including the step of receiving the data on an ISDN B channel.
The method according to any one of 1 to 10. 12. The data of the data server is content of a newspaper article, and the step (b) further includes the step of automatically accessing the host to supply the data at a certain time every day. The method of claim 1, wherein the step (c) further comprises a step of disconnecting the line after receiving the data. 13. A data communication device for supplying data to a plurality of users via a network, the data server transmitting data to be supplied to the user, and the data server connected to the network, A data communication device comprising: a plurality of network interface devices for establishing lines with the plurality of users and supplying the data to the plurality of users, respectively, in response to an access from the user. 14. The data server includes means for repeatedly sending the data.
The described device. 15. The means for repeatedly transmitting the data is a data recording medium.
The described device. 16. The apparatus according to claim 13, wherein the data server further includes means for adding a header to the beginning of the repeated data. 17. A means for converting the data to which the header is added into a plurality of data outputs having stepwise different delay times, and a time until the header arrives when the user makes an access. 17. The system of claim 16, further comprising means for connecting a line from the user to the shortest data output. 18. Means for generating a plurality of data outputs in which the data to which the header is added are repeated stepwise at different timings, and a time until the header arrives when the user accesses the data. 17. The system of claim 16, further comprising means for connecting a line from the user to the shortest data output. 19. The apparatus of claim 14, wherein the data server further comprises means for dividing the data into a plurality of sub-data and adding different unique words. 20. The apparatus according to claim 13, further comprising means for adding an error correction code in the data. 21. Access detection means for detecting the presence or absence of an access from the user by a control signal from the plurality of network interface devices, and supply of data from the data server when there is no access by the control signal. 14. The apparatus according to claim 13, further comprising a data supply stopping means for stopping. 22. A data communication device for receiving data from a host via a network, the first network interface device being connected to the network, accessing the host, and being installed in the host. And a terminal device for processing the data received by the second network interface device, the data communication device comprising: 23. The device according to claim 22, wherein the terminal device further includes a recording unit that records the received data. 24. The device according to claim 22, wherein the terminal device further includes a display for displaying the data. 25. The data includes a header indicating the beginning of the data, and the second network interface device detects the header after establishing the line, and detects the data after the detection. 23. The device according to claim 22, further comprising a header detection unit for sending to the terminal device. 26. The data is composed of a plurality of sub-data each having a different unique word, and the second network interface device sets one of the unique words after establishing the line. 23. After detecting the above, further comprising data reproducing means for receiving all sub-data up to the next same unique word and reproducing the data in order.
The described device. 27. The apparatus of claim 22, further comprising means for receiving the data including an error correction code and correcting an error using the error correction code. 28. Automatic access means for automatically accessing the host to supply the data including the contents of a newspaper article at a certain time every day, and automatic line disconnection means for disconnecting the line after receiving the data. 23. The device of claim 22, further comprising: 29. A mobile terminal main body having a connector for accommodating the second network interface device and the terminal device and capable of being electrically coupled to an external device; and an installation for connecting the connector of the mobile terminal main body to a communication line and a power supply. 23. The device according to claim 22, further comprising a stationary adapter, wherein the electrical coupling is performed by placing the mobile terminal body on the stationary adapter.