JPH0318170A - Computer network - Google Patents

Abstract

PURPOSE:To connect plural terminal equipments freely only at need by connecting an address converter between a general purpose computer and a MODEM and fixing terminal address information from plural lines to the general purpose computer. CONSTITUTION:Terminal equipments 2a-2c have a station address by a procedure of a private line or the like and the address is set identically (such as D). On the other hand, a general purpose computer 1 sends information by a polling selection system. When address information is inputted from the terminal equipments 2a-2c, address converters 6a-6c convert the information into addresses A-C and sends the result to the computer 1 and when the address information sets A-C are inputted from the computer 1 conversely, the information is converted into the address D set to the terminal equipments 2a-2c and the address is sent to the terminal equipments 2a-2c. Thus, plural terminal equipments are connected freely only at need only by utilizing a subscriber telephone network.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a computer network that connects a general-purpose computer as a host computer and terminal computers at remote locations using telephone lines.

[Conventional technology]

When connecting a general-purpose computer and a terminal computer at a remote location using a basic procedure using a telephone line, the link control method is a switched line method that assumes a public line, that is, a subscriber telephone network (including a local telephone network). , a direct line system based on a dedicated line (including a private line) is known.

Among these, the polling selection method is adopted as the circuit control method for the direct line system, in which a general-purpose computer asks each terminal in turn whether it can send or receive data, and the circuit control method for the switched line system is A contention method is adopted in which the side that wants to send data calls the other party and performs communication, and the one that calls the other party first wins the transmission right.

In this way, the circuit control methods are completely different when using a subscriber telephone network and when using a dedicated line, and the software that performs each procedure is IBM's BSC2 in the case of a subscriber telephone network. In the case of a dedicated line, IBM's BSC3 or Hitachi's HSC3 is used. (Hereinafter, the procedures for a subscriber telephone network will be referred to as BS02, etc., and the procedures for a dedicated line will be referred to as BSC3, etc.) On the other hand, computer networks that use a leased line have security that prevents third party intrusion when using a subscriber telephone network. Needless to say, it is relatively expensive, and since the polling/selection method can be used, it is possible to organize the traffic for giving information from the general-purpose computer to the terminal.

[Problem to be solved by the invention]

For example, dedicated lines are often used in networks between large computers and general-purpose computers, or between general-purpose computers, between a head office in Tokyo and a branch office in a regional metropolis.

When attempting to expand the network by connecting a general-purpose computer and a terminal computer (as small as a personal computer) at a remote location using a telephone line, the connection between these general-purpose computers and the terminal computer Regardless of the case where a dedicated line is already in place, the use of a subscriber telephone network is preferable since it would be extremely expensive to install a new dedicated line.

The subscriber telephone network procedure BSC2 etc. and the dedicated line procedure BS
Since the method is completely different from that of C3, etc., it was previously unthinkable to communicate with subscriber telephone networks using BSC3, etc. This is because when a large number of terminals are connected to one general-purpose computer through such a subscriber telephone network, the host cannot recognize which terminal is connected to the general-purpose computer using a polling/selection method such as BSC3. . Therefore, if you decide to do this using a modem that is normally considered, the terminal identification (
(station address, unit address) are unique to each terminal, and it is impossible to freely connect multiple terminals to one terminal identification information on the general-purpose computer side. Therefore, the relationship between a general-purpose computer and a terminal is limited to one-to-one, and a large number of terminals cannot be freely connected to one general-purpose computer.

In addition to communication procedures such as BSC2 and BSC3, there is also a communication procedure called HDLC, which is widely used in the world of large computers, but introducing this requires considerable effort in terms of both hardware and software. There will be a cost.

An object of the present invention is to solve the problems of the conventional example and to provide a computer network that makes it possible to connect a large number of terminals to one general-purpose computer over a subscriber telephone network using a dedicated line procedure 8SC3, etc. It is about providing.

[Means to solve the problem]

In order to achieve the above-mentioned object, when a general-purpose computer and a terminal computer at a remote location are connected using a telephone line using a basic procedure, the telephone line is equipped with a subscriber telephone network having a representative telephone function. A dedicated line transmission control procedure that uses a polling and selection method is used to control the transmission, and a converter for exchanging addresses between the general-purpose computer and the modem is connected, and the general-purpose computer receives terminal addresses from multiple lines. The purpose is to fix information.

[Effect]

According to the present invention, when connecting a plurality of terminals, first the same address is given as the station address of each terminal (this can be done during normal terminal preparation work). Next, on the host side, the address converter according to the present invention operates for each telephone line, and consistent station addresses are repeated to the general-purpose computer, so that the general-purpose computer always responds to multiple terminals with the same station address. Be able to identify.

As a result, a plurality of terminals can be freely connected only when necessary, using a subscriber telephone network via a plurality of modems on the general-purpose computer side.

〔Example〕

FIG. 1 is a block circuit diagram showing one embodiment of the computer network of the present invention. In the figure, 1 is a general-purpose computer as a host computer, 2a, 2b, and 2c are personal computer class terminals, and 3 is a subscriber telephone network. At least on the side where the general-purpose computer 1 is installed, the system has a representative telephone function 3a for receiving a telephone number using a representative telephone number and transmitting it to each telephone.

A modem 4.5 is connected to each of the general-purpose computer 1 and the terminals 2a, 2b, and 2c for connection via a telephone line. As is well known, the modems 4 and 5 are modulation/demodulation devices that perform modulation for converting digital signals into alternating current signals and demodulation for converting alternating current signals into digital signals.

The present invention comprises a general-purpose computer 1 and terminals 2a, 2b, 2c.
Converters 6a, 6b, and 6c for exchanging addresses between the general-purpose computer 1 and the modem 4 are provided when the general-purpose computer 1 and the modem 4 are connected to each other by the subscriber telephone network 3 via the modem 4.5. These converters 6a, 6b, and 6C function as address converters and support the dedicated line procedure BSC3, etc.
When looking at the a, 2b, and 2c sides, a station address conversion function that allows terminals with the same address to be treated as different station addresses on the host side no matter which telephone line they are connected to. In this example, a NEC ■ personal computer 9801 is used.
A mechanism is provided in this personal computer to enable data exchange with the general-purpose computer 1.

Although the general-purpose computer 1 may have only one connection port, it is branched into a plurality of connection ports 1a, lb, and lc as shown in FIG.
, 6b, 6c and modem 4 are connected to this branch connection port 1a, lb,
lc shall be connected to each of the lcs.

Next, the operation will be explained.

Although the terminals 2a, 2b, and 2c have station addresses based on the dedicated line procedure BSC3, etc., they are set to be the same (for example, set to D).

On the other hand, general-purpose computer 1 performs polling and
Information is transported and output using the Seleccigon method.

The converters 6a, 6b, and 6c each output A to the general-purpose computer 1 when address information is input from the terminal.
, B, and C and sent out. Conversely, when the address information of A, B, and C is input from the general-purpose computer 1, the address D set in the terminals 2a, 2b, and 2c is
and sent to the terminal. In this way, the connection port of the representative telephone, which is the connection port on the terminal side, is set so that any connection port can be regarded as a dedicated terminal connection port for station address D.

First, considering the case where converters 6a, 6b, and 6c are not provided, communication with terminals having the same terminal address will naturally not be performed normally.

However, in the present invention, when connecting the terminal 2a to a general-purpose computer, the converter 6a, 6b, 6
Since the address is converted into a unique address of the converter and communication is performed by c, both the general-purpose computer and the terminal can operate normally.

As a result, multiple terminals can be freely connected using the subscriber telephone network only when necessary.

〔Effect of the invention〕

As described above, the computer network of the present invention uses an inexpensive subscriber telephone network for the telephone line when connecting a general-purpose computer and a terminal computer at a remote location using a basic procedure using a telephone line. In addition, it is possible to use dedicated line procedures such as BSC3, which are not compatible with conventional subscriber telephone network procedures such as BSC2, so that the telephone line reception can be done without wasting general-purpose computer software assets and without changing them at all. It is possible to set up multiple devices and connect multiple devices freely and only when necessary.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing one embodiment of a computer network of the present invention, and FIG. 2 is a block diagram showing an application example. l...General-purpose computer la, lb, lc, - connection ports 2a, 2 b. 2 c-Terminal 3...Subscription telephone $4 3a, 3b, 3c...Representative telephone 4.5...Telephone synchronous modem 6a, 6 b, 7...Branching device 6 C...Address conversion vessel

Claims (2)

[Claims] (1) When connecting a general-purpose computer and a terminal computer at a remote location using a basic procedure using a telephone line, a subscriber telephone network with a representative telephone function is used for this telephone line, and the control is based on polling.・It is characterized by using a dedicated line transmission control procedure that adopts a selection method, connecting a converter for exchanging addresses between a general-purpose computer and a modem, and fixing terminal address information from multiple lines to the general-purpose computer. computer network. (2) The general-purpose computer has multiple connection ports by branching.
2. The computer network according to claim 1, wherein a modem is connected via a converter for exchanging addresses at each branch connection port.