JPH053516A - Line terminal equipment - Google Patents

Abstract

PURPOSE:To realize a data communication system without increasing a circuit for connection with the line terminal equipment at a computer even when this system uses two or more public communication lines. CONSTITUTION:A line terminal equipment 1 is interposed between the computer for data communication and the public communication line. This equipment is equipped with an input/output part 2 connected with the computer, plural input/output parts 3 for public line respectively connected to the plural mutually independent public communication lines, and signal conversion circuit 4 to convert data signals bidirectionally exchanged between the computer and the respective public communication lines. Then, based on an instruction from the computer, a control circuit 5 executes the exchange of the data signals between the computer and all or the arbitrary public communication line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog called a modem or DSU which is interposed between a computer and a data communication line when data communication is performed between the computers by using the data communication line. The present invention relates to a line terminal device for a line or a digital line, and particularly to a line terminal device used when performing data communication using a public communication line such as a telephone line.

[0002]

2. Description of the Related Art Conventionally, for example, when a user computer is connected to a predetermined host computer in order to receive a data service, the user computer is connected to one public line via a line terminal device, and also on the host computer side. Connect to a public line via a line terminal. Then, after the user computer calls the host computer, the user computer inputs identification information such as an ID and a password, and if this matches the identification information registered in advance in the host computer, the connection is permitted, and the information service The start was being made.

However, when data communication is performed as described above, if the identification information is illegally obtained by a third party due to the theft or leakage of the ID, password, etc., even if the identification information is illegally obtained identification information, the host The connection will be permitted as long as it matches the identification information on the computer side. For this reason, there has been a problem that there is a risk that the information service is illegally used, or that the program of the host computer or the data held by the host computer is intentionally destroyed or tampered with.

Therefore, the present applicant first prevents illegal connection between computers to prevent illegal use of information services,
We proposed the following data communication method that can eliminate the risk of intentional destruction and falsification of computer programs and data.

That is, as shown in FIG. 7, by inputting identification information from the user computer (100) to the host computer (200) using one public communication line (X), whether the user computer (100) is correct or not. And a procedure for confirming the correctness of the user computer by accessing the user computer (100) from the host computer (200) using a communication line (Y) different from the communication line (X). Proposed was a method for connecting both computers only when it was confirmed that the user computer (100) was authorized by any of the procedures (Japanese Patent Application No. 3-62124).

According to the proposed method, even if a person who illegally obtains the identification information is mistakenly recognized as an authorized user due to the illegal use of the identification information, the confirmation by the access from the host computer cannot be obtained. As long as the two computers are not connected to each other, the unauthorized connection can be surely prevented, and the risk of the unauthorized use of the information service, the intentional destruction of the computer program and the data, and the falsification operation can be significantly reduced.

[0007]

Even in the data communication system according to the above proposal, a line terminal device is provided between the user computer (100), the host computer (200) and the subscriber station line to which they are subscribed. Although it is necessary to intervene, since two different communication lines (X) and (Y) are used in this data communication method, the terminal device must be connected accordingly. In addition, in FIG.
) Is a public communication line network.

However, the conventional public line terminal device is
Since the computer connection input / output unit and the public line connection input / output unit were provided only one to one, as shown in FIG. 7, the lines (X) (Y) and each computer (100) (200) In order to connect with and each requires a total of four line terminal devices (400), and each computer (100) (200) side also has each line terminal device (400)
Had to make a connection to. For this reason, it becomes necessary to add hardware systems such as interface circuits to each computer (100) (200) by the increased number of lines, which leads to a decrease in the processing capacity of the computer and a cost increase. There was a problem.

The present invention has been made in view of the above technical background, and even if it is a data communication system using two or more public communication lines as described above,
An object of the present invention is to provide a line terminal device for this purpose so as to realize this without adding a circuit for connection with the line terminal device to a computer.

[0010]

The above object is a line terminal device interposed between a data communication computer and a public communication line according to the present invention, which is for one computer connected to the computer. An input / output unit, a plurality of public line input / output units each connected to a plurality of mutually independent public communication lines, and conversion of data signals transmitted and received bidirectionally between the computer and each public communication line And a control circuit for transmitting and receiving a data signal between the computer and all or any public communication line based on an instruction from the computer. Achieved by the device.

Alternatively, in a line terminal device interposed between a data communication computer and a public communication line, one computer input / output unit connected to the computer and at least one public communication line are provided. At least one public line input / output unit to be connected, a signal conversion circuit for converting a data signal transmitted and received bidirectionally between the computer and the public communication line, and at least one other line terminal device. A line terminal device input / output unit to be connected and a control circuit for transmitting and receiving a data signal between the computer and the public communication line and / or the other line terminal device based on an instruction from the computer. It is also achieved by a line terminal device characterized by being provided.

Furthermore, a line terminal device interposed between a data communication computer and a public communication line, wherein one computer input / output unit connected to the computer and a plurality of other line terminals. An input / output unit for a plurality of line terminal devices connected to the device, and a control circuit for transmitting and receiving a data signal between the computer and all or any of the line terminal devices based on an instruction from the computer. It is also achieved by a line terminal device characterized by including.

[0013]

A computer is connected to one computer input / output unit of the line terminal device. On the other hand, the public communication line is connected to the public line input / output unit, and another line terminal device is connected to the line terminal device input / output unit. Then, based on an instruction from the computer, the control circuit controls connection / disconnection between the computer and the public communication line or the line terminal device.

[0014]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing a schematic structure of a line terminal device according to a first embodiment of the present invention. This line terminal device (1) includes one computer input / output unit (2).
And two public line input / output units (3) and (3), signal conversion circuits (4) and (4), and a control circuit (5).

The computer input / output unit (2) is directly or indirectly connected to the user computer (10) or the host computer. Note that FIG. 1 shows a case where the user computer (10) is connected. This connection is performed by RS23 like the conventional line terminal device.
This is performed using a serial interface such as 2C or a parallel interface.

The public line input / output units (3) and (3) are
Two independent public communication lines are connected to each other. In this embodiment, one communication line and a total of two communication lines can be connected, but if necessary, three or more public line input / output units are provided to connect three or more public communication lines. Also good.

The signal conversion circuits (4) and (4) convert data signals bidirectionally transmitted and received between the computers (10) and (20) and each public communication line.
For example, in the case of an analog line terminal device, a data signal input from a computer is modulated and output to a public communication line, and a data signal input from the public communication line is demodulated to a computer (10) (20). A modulation / demodulation circuit for outputting is provided.

The control circuit (5) is a computer (1
A computer (1) to enable transmission and reception of data signals between (0) (20) and all or any communication line.
0) It plays a role of controlling connection / disconnection of communication lines to (20). Such connection / disconnection is performed based on a command from the computer (10) (20). For example,
When the computers (10) (20) are connected via the communication line (A), bidirectional data communication between the computers (10) (20) is possible through the line (A),
When the computers (10) and (20) are connected via the communication line (B), bidirectional data communication through the line (B) is possible, and the computers (10) and (20) are communication lines (A). When both are connected via (B), bidirectional data communication is possible by both lines (A) and (B).

A case of performing the data communication according to the above-mentioned applicant's proposal using the line terminal device (1) shown in FIG. 1 and two telephone lines as public lines will be described with reference to FIG. To do.

First, the user side line terminal device (1) is connected to the user computer (10) and the two access subscriber station lines (30) (40) to which the user side subscribes, while the host side line terminal device is connected. The host computer (20) is connected to (1) the two subscriber station lines (50) (60) to which the host side subscribes. Then, by the user computer (10),
The host computer (20) is called through the access subscriber station line (30), the public line network (70), and the host computer side subscriber station line (50). At this time, the control circuit (5) of the user computer (10) is instructed by the user computer (10) and the user computer (10) and the central line (30).
And are connected. By calling the host computer, one data communication line (A) is formed between the user computer (10) and the host computer (20). Identification information such as "ID" and "password" is input from the user computer (10) using the data communication line (A). Such identification information is registered in the host computer (20) in advance. The host computer (20) checks whether the input identification information corresponds to the registered identification information, and if they match, the user computer ( Judge that 10) is legitimate. However, at this stage, the connection is not made yet. If they do not match, it is determined that the user is an unauthorized user and the communication line is disconnected.

Next, the correctness of the user computer (10) is confirmed by accessing the user computer (10) from the host computer (20). The procedure is as follows. That is, when it is confirmed that the user is an authorized user by the identification information from the user computer (10), the host computer (20) uses another station line (60) prepared for access and (60), public network (7
0), the user computer (10) is called via the registered subscriber line (40) for user confirmation. At this time, the control circuit (5) in the line terminal device (1) on the user computer (10) side connects the user computer (10) and the central office line (40) in accordance with an instruction from the user computer (10). The central line (30) is waiting. As a result, a data communication line (B) for accessing from the host computer (20) to the user computer (10) is provided as a data communication line different from the above-mentioned data communication line (A).
Is formed. When using the computer service, it is necessary for the user to previously register the telephone number of the confirmation subscriber station line (40) in the host computer (20) together with the identification information such as “ID” and “password”. The host computer (20) specifies the confirmation subscriber station line (40) based on the identification information sent from the user computer (10) and calls the user computer (10).

The specific means for confirming the correctness of the user computer (10) by the access from the host computer (20) is not particularly limited, but a preferable method is to call the host computer (10) after calling the user computer (10). A method of connecting the access communication line (B) from the user computer (10) to the user computer (10) and the access communication line (A) from the user computer (10) to the host computer (20) can be mentioned. That is, by connecting both communication lines (A) and (B) on the user computer (10) side, the host computer (20) goes around both communication lines (A) and (B) when viewed from the host computer (20) side. )
A large loop-shaped communication circuit for returning to is formed. Then, the presence or absence of this loop communication circuit is confirmed, and if the confirmation is obtained, it is determined that the user is an authorized user, and the connection of the user computer (10) to the host computer (20) is permitted. Thereby, the information of the host computer (20) is appropriately transmitted to the user computer (10), and the user can receive the information service. Conventionally, such a service is provided to an authorized user by accessing from the line (B) and the user computer (10) while the communication line (B) for accessing the user computer (10) from the host computer (20) is connected. Both of the communication lines (A) may be used together, or one of the lines may be disconnected after confirming that the user is an authorized user and only one of the data communication lines may be used. However, it is preferable to use both communication lines (A) and (B) because the communication capacity can be doubled and increased.

On the other hand, if the formation of the loop-shaped communication line is not confirmed, the host computer (20) judges that it is an unauthorized user, disconnects the communication, and disconnects the user computer (1).
Avoid connection 0).

As described above, although the user computer (10) and the line terminal device (1) are connected by one interface, two communication lines (A) and (B) are used.
Can be controlled.

FIG. 3 shows a line terminal device according to a second embodiment of the present invention, and FIG. 4 is a connection conceptual diagram of a user computer (10) and a host computer (20) using the terminal device. is there. In this embodiment, at least one other public line input / output unit (3) is provided with at least one other line terminal input / output unit (6), and the public line input / output unit (3) is provided. In the public communication line, other line terminal devices (80) are connected to the line terminal device input / output unit (6). Then, the control circuit (5) controls transmission / reception of a data signal between the computer and the public communication line and / or the other line terminal device (80) based on an instruction from the computer (10) (20). It is supposed to be.

Also in this embodiment, the computer (1
0) and the line terminal device (1) are connected to each other through one interface, and the public line is controlled through this interface.

FIG. 5 shows a line terminal device according to a third embodiment of the present invention, and FIG. 6 is a connection conceptual diagram of a user computer (10) and a host computer (20) using the terminal device. is there. In this embodiment, at least two line terminal device input / output units (6) and (6) respectively connected to at least two line terminal devices (80) (80) are provided, and the control device (5 ) By computer (1
0) (20) controls transmission and reception of data signals between the computer and all or arbitrary line terminal devices (80) on the basis of instructions.

Also in this embodiment, the computer (1
The 0) (20) and the line terminal device (80) are connected via one interface, and the public line is controlled via this interface.

3 to 6, parts having the same names as those shown in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

[0031]

According to the line terminal device of the present invention,
A computer connected to one computer input / output unit can freely control connection or non-connection of a plurality of mutually independent public communication lines directly or through another line terminal device. Therefore, even when implementing a data communication method for confirming the correctness of a user computer using two or more public communication lines, the existing computer having an interface for connection with one line terminal device is used as it is. Therefore, it is possible to eliminate the need to add an interface of the computer according to the increase in the number of communication lines, and it is possible to avoid a decrease in the capacity of the computer and an increase in cost due to the addition of the interface.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a line terminal device according to a first embodiment of the present invention.

FIG. 2 is a connection conceptual diagram when performing data communication between computers using the line terminal device shown in FIG.

FIG. 3 is a block diagram showing a configuration of a line terminal device according to a second embodiment of the present invention.

FIG. 4 is a connection conceptual diagram when performing data communication between computers using the line terminal device shown in FIG.

FIG. 5 is a block diagram showing a configuration of a line terminal device according to a third embodiment of the present invention.

6 is a connection conceptual diagram in the case of performing data communication between computers using the line terminal device shown in FIG.

FIG. 7 is a connection conceptual diagram when performing data communication between computers using a conventional line terminal device.

[Explanation of symbols]

1 ... Line terminal device 2 ... Computer input / output section 3 ... Public line input / output unit 4 ... Signal conversion circuit 5 ... Control circuit 6 ... I / O unit for public line

Claims (3)

[Claims] 1. A line terminal device interposed between a data communication computer and a public communication line, comprising one computer input / output unit connected to the computer.
A plurality of public line input / output units respectively connected to a plurality of public communication lines independent of each other, and a signal conversion circuit for converting data signals bidirectionally transmitted and received between the computer and each public communication line And a control circuit for transmitting and receiving a data signal between the computer and all or any public communication line based on an instruction from the computer. 2. A line terminal device interposed between a data communication computer and a public communication line, comprising one computer input / output unit connected to the computer.
At least one connected to at least one public communication line
Public line input / output unit, a signal conversion circuit for converting data signals transmitted and received bidirectionally between the computer and the public communication line, and a line terminal connected to at least one other line terminal device. And a control circuit for transmitting and receiving a data signal between the computer and the public communication line and / or the other line terminal device based on an instruction from the computer. A characteristic line terminal device. 3. A line terminal device interposed between a data communication computer and a public communication line, and one computer input / output unit connected to the computer.
A plurality of line terminal device input / output units connected to other plurality of line terminal devices, and transmission / reception of data signals between the computer and all or any of the line terminal devices based on an instruction from the computer. And a control circuit for performing the above.