JPH09298562A - Remote data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the futile usage charge of a line connecting a user terminal to a connection host by disconnecting the line during the transmission of request data from an information server to the connection host when the time of transmission is longer than the threshold value. SOLUTION: A connection host 2 stores the data amount information of request data received from an information server 3 into a data amount detecting means 11, transmits the request data through a 1st line 4 to a user terminal 1 and stores them in a data buffer 15 so as not to be erased or overwritten. Besides, parallelly with the reception of these request data, the connection host 2 measures its communication velocity through a communication velocity measuring means 12. Then, a required communication time predicting means 13 predicts the time required for communicating the request data from the outputs of the data amount detecting means 11 and the communication velocity measuring means 12 and when this predictive value is higher than the threshold value, a communication interruption discriminating means 14 disconnects the 1st line 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a remote data communication device for performing data communication with an information server from one or more user terminals such as P connection via a connection host.

[0002]

2. Description of the Related Art In recent years, a method such as dial-up IP connection has been used as an inexpensive method for individuals or small groups to access a large-scale network such as the Internet. Figure 9 shows the conventional dial-up IP
Connection configuration, FIG. 10 shows a conventional dial-up IP connection procedure.

An outline of dial-up IP connection will be described below with reference to FIGS. 9 and 10. In FIG. 9, 100
0 is a user terminal, 1001 is a connection host, 1002 is an information server, 1003 is a first line, 1004 is a second line, 1005 is an information storage means, and 10
Reference numerals 06, 1007, 1008 and 1009 denote communication interfaces.

First, the user terminal 1000 transmits a line connection request to the connection host 1001 via the communication interfaces 1006 and 1007 and the first line 1003 (procedure 0-a). The connection host 1001 is the user terminal 1
After the authentication procedure such as the password of 000, the line connection of the user terminal 1000 is permitted (procedure 0-b). As a result, the user terminal 1000 is connected to the second line 1004 via the connection host 1001 by the information server 10
It is possible to access the data stored in the information storage unit 1005 in the 02.

Next, when a transmission request for data stored in the information storage means 1005 in the information server 1002 is transmitted from the user terminal 1000 to the connection host 1001 (procedure 1-a), the connection host 1001 This request is sent to the communication interfaces 1008 and 1009 and the second line 1.
The information is transmitted to the information server 1002 via 004 (procedure 1-b).

The information server 1002 retrieves the requested data from the information storage means 1005, and through the communication interfaces 1009 and 1008 and the second line 1004,
It is transmitted to the connection host 1001 (procedure 2-a).

The connection host 1001 is the information server 100.
The request data received from the communication interface 10
07, 1006 and the first line 1003, and transmits to the user terminal 1000 (procedure 2-b).

By the above procedure, the user terminal 1000 can acquire the data on the information server 1002 which is not directly connected. The above is the outline of data acquisition using the dial-up IP connection. In general, one connection host often has a plurality of communication interfaces for connecting lines of user terminals so that lines of a plurality of user terminals can be connected.

Further, in the conventional dial-up IP connection as described above, when the same request data is accessed from one terminal a plurality of times or the same request data is accessed from different terminals, the second As a technique for reducing the traffic on the line, there is a technique for providing a cache in the connected host. FIG. 11 shows the configuration of the connected host with cache, and FIG. 12 shows the procedure of data acquisition by dial-up IP connection using the connected host with cache.

An outline of data acquisition using a connected host with a cache will be described below with reference to FIGS. 11 and 12.

In FIG. 11, 1000 is a user terminal,
1001 is a connection host, 1002 is an information server,
1003 is the first line, 1004 is the second line,
An information storage unit 1005 includes 1006, 1007,
Reference numerals 1008 and 1009 denote communication interfaces, and 20
00 is a cache means.

The difference from the dial-up IP connection shown in FIGS. 9 and 10 is that the connecting host 1001 is connected to the information server 100.
The request data received from No. 2 is stored not only in the user terminal 1000 but also in the cache unit 2000 (procedure 2-c).

As a result, when the user terminal 1000 makes a second or subsequent request for the stored request data, instead of communicating with the information server 1002,
The data on the cache means 2000 is used. This can reduce the traffic on the second line.

In this case, when requests for other data from the information server 1002 are sequentially received from the user terminal 1000, when the data cannot be stored on the cache means 2000 or after the data is stored on the cache means 2000, For data that has passed a certain period of time, the data in the cache means 2000 is updated by, for example, erasing or overwriting old data.

In the conventional dial-up IP connection as described above, since a general telephone line or ISDN line is often used as the first line, the charge for using the first line is a line connection request. User terminal 100
0 side bears. There is a technique called callback as a technique that places this on the connection host 1001 side.

FIG. 13 shows a data acquisition procedure by dial-up IP connection using a connection host having a callback function.

An outline of data acquisition using a connection host with a cache will be described below with reference to FIG.

In FIG. 13, 1000 is a user terminal,
1001 is a connection host, 1002 is an information server,
An information storage unit 1005 is provided.

The points different from the dial-up IP connection shown in FIGS. 9 and 10 are the user terminal 1000 and the connection host 1001.
Immediately after the line connection of the first line is performed, the first line is disconnected from the connecting host 1001 side. Then, the user terminal 1000 prepares for the line recovery request from the connecting host (procedure 1-b).

Next, the connection host 1001 uses the user terminal 1000 used when the first line connection is made.
The line connection destination (telephone number, etc.) of the user terminal 1000 is known from the password information of
A line recovery request is made to 000 (procedure 2-a).
On the other hand, the user terminal 1000 uses the connection host 100
1 line connection is permitted (procedure 2-b), and the user terminal 10
00 and the connection host 1001 complete the line connection. Subsequent data transmission requests and request data transmission procedures are performed in the same manner.

As a result, the line connection between the user terminal 1000 and the connection host 1001 requested by the user terminal 1000 side is temporarily interrupted, and the connection host 1001 side recovers. Can be borne by the connection host 1001 side instead of the user terminal 1000 side.

[0022]

However, in the above-mentioned conventional dial-up IP connection, when it takes a long time to transmit request data from the information server to the connecting host,
In particular, if the information server cannot send the requested data at a sufficient speed for some reason, or if the communication speed of the second line is low due to the congestion of the second line, etc. Even if it becomes a bottleneck and the communication speed of the first line does not come out sufficiently, or the actual data communication on the first line is hardly performed,
The connection of the first line between the user terminal and the connecting host is still maintained, and the charge for the first line is wasted because it is charged according to the connection time for general telephone lines and ISDN lines. .

Further, even in the dial-up IP connection using the connection host with a cache as described above, if there is no requested data in the cache, the same waste cannot be avoided. In addition, dial-up IP using the connecting host having the above-mentioned callback function
Even in connection, the same waste is not on the user terminal side,
Occurs on the connecting host side.

Therefore, according to the present invention, in order to solve the above-mentioned problem, it is automatically judged when it takes a long time to transmit the request data from the information server 1002 to the connecting host 1001, and the request data is being transmitted. It is an object of the present invention to provide a remote data communication device including a dial-up IP connection, which prevents the use fee of the first line from being wasted by disconnecting the first line 1003.

[0025]

In order to achieve the above object, a remote data communication device according to the present invention, when request data is requested from the user terminal, sends information on the data amount of the request data from an information server. A data amount detecting means for acquiring and outputting, a communication speed measuring means for measuring and outputting a communication speed at which requested data is communicated, and a communication of request data by receiving outputs of the data amount detecting means and the communication speed measuring means. A required communication time predicting means for predicting and outputting the required time, and a communication interruption determining means for issuing an instruction to disconnect the first line when the estimated time output by the required communication time predicting means exceeds a certain threshold, The request data sent from the information server is temporarily sent while the communication between the user terminal and the connection host is interrupted by the instruction of the communication interruption determination means inside the connection host. It has a data buffer that makes it impossible to erase or overwrite that area, and after the communication of the requested data is completed, the connection of the first line is restored and stored in the area on the data buffer for the user terminal. It is characterized in that the area on the data buffer storing the request data can be erased or overwritten after the request data is communicated from the connection host. As a result, even when the time required to transmit the request data from the information server to the connecting host is long (because it is longer than the above threshold) due to the reason attributed to the information server or the second line, Since the connection of the first line is disconnected during the transmission of request data, it is possible to almost eliminate the wasteful connection time on the first line, resulting in the waste of the usage charge of the first line. Can be prevented.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a configuration diagram of a first embodiment of a remote data communication apparatus of the present invention. In FIG. 1, 1 is a user terminal, 2 is a connection host, 3 is an information server, 4 is a first line, 5 is a second line,
Reference numeral 6 is an information storage means, 7, 8, 9, and 10 are communication interfaces, 11 is a data amount detecting means, 12 is a communication speed measuring means, 13 is a required communication time predicting means, 14 is a communication interruption determining means, Reference numeral 15 is a data buffer, and 16 is a data switch.

FIG. 2 is a diagram showing an operation procedure of the first embodiment of the remote data communication apparatus of the present invention.

The first part of the remote data communication device of the present invention will be described below.
The operation of this embodiment will be described with reference to FIGS. 1 and 2.

2 (procedure 0-a), (procedure 0-b),
User terminal 1 up to (procedure 1-a) and (procedure 1-b)
From the connection request to the connection host 2 via the first line 4 and the connection permission, the data transmission request from the user terminal 1 to the connection host 2, and the data transmission request from the connection host 2 to the information server 3 Is similar to the conventional dial-up IP connection.

Subsequently, the information server 3 retrieves the requested data from the information storage means 6, and the communication interface 1
0, 9 and the second line 5 are transmitted to the connecting host 2. At this time, at the beginning of the transmission of the request data from the information server 3 to the connecting host 2, the data amount information of the request data is transmitted. (Procedure 2-a).

The connecting host 2 first stores the data amount information of the request data received from the information server 3 in the data amount detecting means 11, and subsequently, the request data is transmitted to the communication interfaces 8 and 7 and the first line. The request data is also stored in the data buffer 15 at the same time as it is transmitted to the user terminal 1 via 4 (procedure 2-b), and cannot be erased or overwritten (procedure 2-c). This operation is similar to the conventional data acquisition by dial-up IP connection using the connected host with cache, but in the conventional example, it is only a cache, and overwriting or erasing of requested data may occur at any time. In addition, there is no guarantee that the requested data exists. On the other hand, in the present invention, the data buffer cannot be erased or overwritten, so that it can be guaranteed that the requested data exists in the data buffer 15.

Further, the connection host 2 measures the communication speed for receiving the request data by the communication speed measuring means 12 in parallel with the reception of the request data from the information server 3. The required communication time predicting means 13, which receives the output of the data amount detecting means 11 and the output of the communication speed measuring means 12, determines the data amount of the requested data output by the data amount detecting means 11 from the communication speed output from the communication speed measuring means 12. The time required to communicate the requested data is estimated by dividing by. The communication interruption judging means 14 compares the output of the required communication time predicting means 13 with a predetermined threshold value (for example, 30 seconds). If the threshold value is larger, the first line 4 is not disconnected. Further, the communication is continued as it is until the communication of the request data is completed, and after the communication of the request data is completed, the area where the request data is accumulated in the data buffer 15 can be erased or overwritten. If the threshold value is smaller, the following operations are sequentially performed.

First, the communication interruption judging means 14 gives an instruction to disconnect the first line 4 (procedure 3-a), and in response thereto, the connecting host 2 requests the user terminal 1 to disconnect the line (procedure 3). 3-b). The user terminal 1 disconnects the line and then prepares for a line recovery request from the connecting host (procedure 3-c).

While the first line is disconnected, the request data is continuously stored in the data buffer 15 from the information server 3. After receiving the requested data, data buffer 1
When the storage in 5 is completed, the data buffer 15 generates a storage end signal (procedure 4-a). In response to this, the connection host 2 makes a line recovery request to the user terminal 1 (procedure 4-b). On the other hand, the user terminal 1 permits the line recovery of the connection host 2 (procedure 4-c), and the recovery of the first line 4 is completed.

The accumulation end signal from the data buffer 15 is also sent to the data switch 16, and the data transmitted from the communication interface 8 to the connecting host 2 is switched to the data from the data buffer 15.

The connection host 2 transmits the request data accumulated in the data buffer 15 to the user terminal 1 through the restored first line 4 (procedure 5-a). When the transmission of the request data is completed, the connecting host 2 can erase or overwrite the area where the request data is stored in the data buffer 15 (procedure 5-b).

As a result, when the time required to transmit the request data from the information server to the connecting host is long (because it is longer than the above threshold value) due to the reason being attributed to the information server or the second line. Also, while sending the request data,
Since the connection of the first line is disconnected, it is possible to almost eliminate the wasteful connection time in the first line.

(Second Embodiment) FIG. 3 is a block diagram of a second embodiment of the remote data communication apparatus of the present invention. In FIG. 3, 1 is a user terminal, 2 is a connection host, 3 is an information server, 4 is a first line, 5 is a second line,
Reference numeral 6 is an information storage means, 7, 8, 9, and 10 are communication interfaces, 11 is a data amount detecting means, 12 is a communication speed measuring means, 13 is a required communication time predicting means, 14 is a communication interruption determining means, Reference numeral 15 is a data buffer, 16 is a data switch, and 17 is a timer.

FIG. 4 is a diagram showing an operation procedure of the second embodiment of the remote data communication apparatus of the present invention.

The second part of the remote data communication device of the present invention will be described below.
The operation of this embodiment will be described with reference to FIGS.

(Procedure 0-a), (Procedure 0-b),
(Procedure 1-a), (Procedure 1-b), (Procedure 2-a),
Connection procedure and connection permission by the first line 4 from the user terminal 1 to the connection host 2 through (procedure 2-b), (procedure 2-c), and (procedure 3-a), the user terminal 1 to the connection host 2, data transmission request from the connection host 2 to the information server 3, data transmission request from the information server 3 to the connection host 2, data transmission request from the connection host 2 to the user terminal 1. The operation of accumulating the requested data in the data buffer and the operation until the communication interruption determining means 14 instructs the disconnection of the first line 4 are the same as those in the first embodiment.

The connection host 2 instructed to disconnect the first line 4 from the communication interruption determining means 14 instructs the user terminal 1 to
First, the predicted value of the time required for communication of the request data output from the required communication time prediction means 13 is performed through the first line, and the user terminal 1 stores the predicted value as the initial value of the timer 17 (procedure 3-b1). ). Subsequently, the connection host 2 makes a line disconnection request to the user terminal 1 (procedure 3-b2). The user terminal 1 disconnects the line and simultaneously starts counting by the timer 17. When the timer 17 finishes counting, that is, when the estimated value of the required communication time has passed (procedure 4-a), this is used as a trigger to trigger the user terminal 1
Makes a line recovery request to the connecting host 2 (procedure 4-b). On the other hand, the connection host 2 is the user terminal 1
Is permitted (procedure 4-c), and the restoration of the first line 4 is completed.

Unlike the first embodiment, the accumulation of the requested data from the information server 3 to the data buffer 15 is not always completed at this point. Therefore, the reception of the requested data is completed, the accumulation in the data buffer 15 is completed, the data buffer 15 generates the accumulation end signal, and the data switch 16 transmits the data transmitted from the communication interface 8 to the connection host 2 to the data buffer. Waiting for switching to the data from 15 (procedure 5-a), the connecting host 2 transmits the request data accumulated in the data buffer 15 to the user terminal 1 (procedure 5-b). When the transmission of the request data is completed, the connection host 2 can erase or overwrite the area where the request data is stored in the data buffer 15 (procedure 5-c).

As described above, in the second embodiment, the first
In comparison with the embodiment of the first embodiment, the operation of the user terminal waiting for the line recovery request from the connecting host is not required in the recovery of the first line, and the user terminal only needs to have a function of requesting the line connection. Since the host only needs to have the function of waiting for the line connection request, not only the effect obtained by the first embodiment but also the effect that the function related to the line connection between the user terminal and the connected host can be simplified can be realized.

(Third Embodiment) FIG. 5 is a block diagram of a third embodiment of the remote data communication apparatus of the present invention. In FIG. 5, 1 is a user terminal, 2 is a connection host, 3 is an information server, 4 is a first line, 5 is a second line,
Reference numeral 6 is an information storage means, 7, 8, 9, and 10 are communication interfaces, 11 is a data amount detecting means, 12 is a communication speed measuring means, 13 is a required communication time predicting means, 14 is a communication interruption determining means, Reference numeral 15 is a data buffer, and 16 is a data switch.

FIG. 6 is a diagram showing an operation procedure of the third embodiment of the remote data communication apparatus of the present invention.

The third embodiment of the remote data communication device of the present invention will be described below.
The operation of this embodiment will be described with reference to FIGS.

(Procedure 0-a), (Procedure 0-b) of FIG.
(Procedure 1-a), (Procedure 1-b), (Procedure 2-a),
User terminal 1 up to (procedure 2-b) and (procedure 2-c)
From the user terminal 1 to the connection host 2 via the first line 4, connection permission, data transmission request from the user terminal 1 to the connection host 2, and data transmission request from the connection host 2 to the information server 3, the information server 3 From the transmission of the request data from the connection host 2 to the connection host 2, the transmission of the request data from the connection host 2 to the user terminal 1, and the storage of the request data in the data buffer are almost the same as those in the first embodiment.

However, the difference from the first embodiment is that the data amount detecting means 11, the communication speed measuring means 12, the required communication time predicting means 13 and the communication interruption determining means 14 are provided in the user terminal 1.
The user terminal 1 is notified of the data amount information of the request data received by the connection host 2 from the information server 3 and is stored in the data amount detection means 11 via the first line 4. The communication speed of the request data received by the communication speed measuring means 12 is measured for the first line 4 using the communication interface 7. The user terminal 1 side also determines whether or not to disconnect the first line (procedure 3-a), and a request to disconnect the first line 4 is issued from the user terminal 1 to the connection host 2. Performed (procedure 3
-B).

Thereafter, (procedure 4-a) and (procedure 4-a) in FIG.
b), (procedure 5-a), and (procedure 5-b), the accumulation of the requested data in the data buffer 15 is completed, the line recovery request from the connecting host 2 to the user terminal 1 and the user terminal 1
Connection permission to the host 2 connected to the server, data buffer 15
The transmission of the request data accumulated above and the operation of erasing or overwriting the area where the request data is accumulated are exactly the same as in the first embodiment.

As described above, in the third embodiment, the first
Compared to the above embodiment, a large part of the function on the connection host is moved to the user terminal side. As described above, the normal connection host performs the same operation for a plurality of user terminals at the same time. Therefore, by moving the function to the user terminal side, the processing load of the connection host is significantly reduced. This can be realized together with the effect obtained by the first embodiment.

(Fourth Embodiment) FIG. 7 is a block diagram of a fourth embodiment of the remote data communication apparatus of the present invention. In FIG. 7, 1 is a user terminal, 2 is a connection host, 3 is an information server, 4 is a first line, 5 is a second line,
Reference numeral 6 is an information storage means, 7, 8, 9, and 10 are communication interfaces, 11 is a data amount detecting means, 12 is a communication speed measuring means, 13 is a required communication time predicting means, 14 is a communication interruption determining means, Reference numeral 15 is a data buffer, 16 is a data switch, and 17 is a timer.

FIG. 8 is a diagram showing an operation procedure of the fourth embodiment of the remote data communication apparatus of the present invention.

The fourth embodiment of the remote data communication device of the present invention will be described below.
The operation of this embodiment will be described with reference to FIGS. 7 and 8.

(Procedure 0-a), (Procedure 0-b) of FIG.
(Procedure 1-a), (Procedure 1-b), (Procedure 2-a),
(Procedure 2-b), (Procedure 2-c), (Procedure 3-a),
Up to (procedure 3-b), the user terminal 1 to the connection host 2
Connection request and connection permission by the first line 4 to the connection host 2, data transmission request from the user terminal 1 to the connection host 2, data transmission request from the connection host 2 to the information server 3, information server 3 from the connection host 2 Request data to the user terminal 1, request data from the connection host 2 to the user terminal 1, storage of request data in a data buffer, communication interruption determining means 14
Regarding the instruction to disconnect the first line 4 and the operation from the user terminal 1 to the connection host 2 to disconnect the first line 4, the same as in the third embodiment.

The point different from the third embodiment is that the user terminal 1 has a timer 17 and the user terminal 1 can disconnect the first line 4 before or after disconnecting it. The predicted value of the time required for communication of the request data output from the required communication time prediction means 13 is stored as the initial value of the timer 17, and the timer 17 starts counting. When the timer 17 finishes counting, that is, when the estimated value of the required communication time has elapsed (procedure 4-a), this is used as a trigger,
The user terminal 1 makes a line recovery request to the connection host 2 (procedure 4-b). On the other hand, the connection host 2 permits the line recovery of the user terminal 1 (procedure 4-c), and the recovery of the first line 4 is completed.

Unlike the third embodiment, the accumulation of the request data from the information server 3 to the data buffer 15 is not always completed at this point, as in the second embodiment. . Thereafter, as in the second embodiment, (procedure 5-a), (procedure 5-b), and (procedure 5) in FIG.
-C), the accumulation of the requested data in the data buffer 15 is completed, the data switch 16 is switched, the requested data of the connecting host 2 is transmitted to the user terminal 1, and the requested data in the data buffer 15 is accumulated. The operation is performed until the existing area can be erased or overwritten.

As described above, in the fourth embodiment, the first
In addition to the effect obtained by the embodiment described above, the effect obtained by the second embodiment can be realized and the effect obtained by the third embodiment can also be realized together.

In the above description, the example of the configuration in which the user terminal, the information server, the first line, and the second line are all one has been described. However, these are two or more configurations. However, the present invention can be implemented similarly.

Although not particularly mentioned in the above description, it is obvious that after the data buffer is made overwritable or erasable, it can be used as a cache in a conventional connected host with a cache.

Although not particularly mentioned in the above description, the data buffer is a ring buffer or a FIFO.
If realized by, in Embodiments 2 and 4,
It is also clear that the transmission of the requested data from the connecting host to the user terminal can be started without waiting for the completion of the accumulation of the requested data in the data buffer.

[0063]

As described above, according to the present invention, the time required for transmitting the request data from the information server to the connecting host is long due to the information server and the second line. In this case, since the connection of the first line is cut off during the transmission of the request data, it is possible to almost eliminate the wasteful connection time on the first line. It is possible to prevent the waste of.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of a remote data communication device of the present invention.

FIG. 2 is an explanatory diagram showing an operation procedure of the embodiment.

FIG. 3 is a configuration diagram of a second embodiment of a remote data communication device of the present invention.

FIG. 4 is an explanatory diagram showing an operation procedure of the embodiment.

FIG. 5 is a configuration diagram of a third embodiment of a remote data communication device of the present invention.

FIG. 6 is an explanatory diagram showing an operation procedure of the embodiment.

FIG. 7 is a configuration diagram of a fourth embodiment of a remote data communication device of the present invention.

FIG. 8 is an explanatory diagram showing an operation procedure of the embodiment.

FIG. 9 is a block diagram of a conventional remote data communication device for making a dial-up IP connection.

FIG. 10 is an explanatory diagram showing a procedure of a conventional dial-up IP connection.

FIG. 11 is a block diagram of a conventional remote data communication device for performing dial-up IP connection using a connection host with a cache.

FIG. 12 is an explanatory diagram showing an operation procedure of a conventional remote data communication device that performs dial-up IP connection using a connection host with a cache.

FIG. 13 is an explanatory diagram showing an operation procedure of a remote data communication device that performs dial-up IP connection using a connection host having a conventional callback function.

[Explanation of symbols]

 1 User terminal 2 Connection host 3 Information server 4 First line 5 Second line 11 Data amount detecting means 12 Communication speed measuring means 13 Required communication time predicting means 14 Communication interruption judging means 15 Data buffer 17 Timer

Claims (5)

[Claims] 1. A user terminal, an information server, and the user terminal are connected by a first line, the information server is connected by a second line, and the user terminal is connected via the first line. Remote data communication composed of a connection host that receives request data stored on the information server via the second line in response to a request and transmits the request data to the user terminal via the first line. An apparatus, which communicates the request data with a data amount detection means that acquires and outputs information on the data amount of the request data from the information server when the request data is requested from the user terminal. Communication speed measuring means for measuring and outputting the communication speed, receiving the outputs of the data amount detecting means and the communication speed measuring means, predicting and outputting the time required for communication of the requested data Inside the connected host, there is a communication time required prediction means, a communication interruption determination means for issuing an instruction to disconnect the first line when the predicted time output by the required communication time prediction means exceeds a certain threshold value. There is a data buffer that temporarily stores the request data sent from the information server and disables erasing or overwriting of the area of the request data. After the connection is restored and the request data stored in the area on the data buffer is communicated to the user terminal from the connection host, the area on the data buffer storing the request data is erased or overwritten. A remote data communication device characterized by being capable. 2. The connection host has the data amount detecting means, the communication speed measuring means, the required communication time predicting means, and the communication interruption determining means, and the data buffer has accumulated all the requested data. 2. The remote data communication apparatus according to claim 1, wherein a storage end signal indicating the above is output, and the connection end side of the data buffer is used as a trigger to restore the connection of the first line from the connection host side. . 3. The connecting host has the data amount detecting means, the communication speed measuring means, the required communication time predicting means, and the communication interruption judging means, and the connecting host before disconnecting the first line. The user terminal has a timer for notifying the user terminal of the output of the required communication time predicting means and outputting a time lapse signal indicating that the time output by the required communication time predicting means has passed. 2. The remote data communication device according to claim 1, wherein the connection of the first line is restored from the user terminal side by using the time lapse signal of the timer as a trigger. 4. The user terminal has the data amount detecting means, the communication speed measuring means, the required communication time predicting means, and the communication interruption determining means, and the data buffer has accumulated all the requested data. 2. The remote data communication apparatus according to claim 1, wherein a storage end signal indicating the above is output, and the connection end side of the data buffer is used as a trigger to restore the connection of the first line from the connection host side. . 5. The user terminal has the data amount detecting means, the communication speed measuring means, the required communication time estimating means, and the communication interruption determining means, and the time output by the required communication time estimating means has elapsed. The user terminal has a timer that outputs a time lapse signal indicating that the connection of the first line is restored from the user terminal side using the time lapse signal of the timer as a trigger. 1. The remote data communication device according to 1.