JPH06112946A - Transmission medium selection method - Google Patents

Abstract

PURPOSE:To attain accurate data transmission by surely selecting a prescribed transmission line (transmission medium) available of communication and connecting a terminal equipment and the prescribed transmission line. CONSTITUTION:In the transmission medium selection method in which a prescribed transmission available of communication is selected by a transmission line selector 12 from transmission lines 15, 16 corresponding to plural different 1st and 2nd networks to connect the prescribed transmission line to a terminal equipment, a reflection recognition circuit 11 recognizes whether or not a transmission of a network available of communication is connected to the terminal equipment by utilizing a reflection wave of transmission data and when the circuit 11 recognizes a reflection wave, the circuit 11 outputs a select signal to the transmission line selector 12 to control it and to allow the selector 12 to revise the transmission line connecting to the terminal equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission medium selection method for connecting a communicable transmission line (transmission medium) used in a LAN (local area network) or the like and a terminal device.

[0002]

2. Description of the Related Art Conventionally, in order to connect a transmission medium and a terminal device, a manual switch is provided, and the manual switch is connected to a transmission line which is a transmission medium of each network, and a network interface described above. It is interposed between the terminal device. Then, the operator manually operates the manual switch to select the network interface to which the communicable transmission medium is connected and connect the network interface and the terminal device.

More specifically, a case where the terminal device is a personal computer (personal computer) will be described. The option card of the above personal computer is a transceiver card (LAN) for connecting the personal computer to the network.
Card) may be provided. This card has
So that the personal computer can be connected to any transmission medium,
There are cases where a plurality of network interfaces are provided, and basically, only one of these transmission interfaces can be selected from a plurality of transmission media. In this case, it is not necessary to connect the cables of the personal computer to all the interfaces, and if you want to connect to a different transmission medium, connect the personal computer and the transmission medium and remove the transmission medium that has been used up to now. . In such a case, the network interface connected to the personal computer is switched using the manual switch to connect the personal computer to a specific transmission medium.

[0004]

However, in the above transmission medium selection method, switching reliability is greatly impaired due to incorrect switching of the manual switch, poor contact inside the switch, etc., and reliable selection of the transmission path is not possible. There was a problem that it could not be done. The present invention has been made in view of the above problems, and provides a transmission medium selection method capable of reliably switching to a predetermined transmission medium with which communication is possible and connecting the predetermined transmission medium and a terminal device. With the goal.

[0005]

In order to achieve the above object, in the present invention, the selecting means selects a predetermined transmission medium capable of communication from among transmission media corresponding to a plurality of different networks, and the predetermined transmission is performed. In a transmission medium selecting method for connecting a medium and a terminal device, a reflection recognizing unit recognizes a reflected wave of data transmitted to a transmission medium connected to the terminal device, and the selecting unit according to the recognition of the reflected wave. There is provided a transmission medium selection method for controlling the transmission medium to change the transmission medium connected to the terminal device.

[0006]

In general, when the transmission medium is not connected to the network interface and the data is transmitted to the network interface, a reflected wave of the data is generated and transmission becomes impossible. Therefore, in order to recognize the connected transmission medium, the presence or absence of the reflected wave of the transmitted data is recognized by the reflection recognition circuit which is the reflection recognition means. Here, when the reflected wave is recognized, the reflection recognition circuit determines that the transmission medium connected to the network interface other than the network interface connected up to now can communicate, and controls the transmission path selector that is the selection means. Then, the transmission medium connected to the terminal device is changed.

Therefore, it is possible to automatically switch the transmission medium, prevent physical failures such as switching error due to a manual switch or contact failure inside the switch, and perform data transmission by selecting an accurate transmission medium. become.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawing of FIG. FIG. 1 is a block diagram showing the configuration of an apparatus using the transmission medium selection method according to the present invention. In the figure, the transmission medium selection device includes a reflection recognition circuit 11 that recognizes a reflected wave of data to be transmitted, and a transmission line selector 12 that switches a transmission line that is a transmission medium.

The reflection recognition circuit 11 outputs the data transmitted from the terminal device to the transmission lines 15 or 16 of the first and second networks which can communicate with each other via the transmission line selector 12 and the network interface 13 or 14. At the same time, the presence or absence of a reflected wave for the data from the network interface 13 or 14 is recognized. Here, when the reflection recognition circuit 11 does not recognize the generation of the reflected wave, it is determined that the reflection recognition circuit 11 is connected to the transmission path of the communicable network, and when the generation of the reflected wave is recognized,
When it is determined that the transmission path of the communicable network is not connected, a select signal is output to the transmission path selector 12 to control the switching of the transmission path.

The transmission path selector 12 is a reflection recognition circuit 11
Transmission lines 15 and 16 connected via the network interfaces 13 and 14 based on the select signal from the
And the data transmission path and the reflected wave reception path are selected. Network interface 13,
Reference numeral 14 denotes different types of transmission lines 15 and 16 and B (not shown).
It is connected via a connector such as an NC receptacle or a D-sub connector to enable data transmission between the terminal device and each network.

Next, the operation of the transmission medium selection device according to the transmission medium selection method of the present invention will be described. In the above description of the operation, the transmission line 15 is not connected to the network interface 13 shown in FIG.
Is connected, and the transmission path selector 12 is connected to the network interface 13 at an initial stage.

First, when data is transmitted from the terminal device to the network interface 13 via the reflection recognition circuit 11 and the transmission path selector 12, a reflected wave is generated from the network interface 13. Reflection recognition circuit 11
Recognizes the reflected wave input via the transmission path selector 12, and determines that the transmission path is not connected to the network interface 13 because reflection has occurred. Then, the reflection recognition circuit 11 uses the transmission path selector 12
A select signal is output to the switch to switch the transmission path. Thus, the transmission path selector 12 is connected to the network interface 14, and the data from the terminal device is transmitted to the network interface 14.

Next, the reflection recognition circuit 11 waits for the reflection from the network interface 14 for a predetermined time. In this case, since the reflected wave cannot be recognized, a transmission line is connected to the network interface 14. Then, it is determined that the transmission path capable of communicating with the terminal device is connected, and the transmission of the data is continued. Also,
When the transmission path is not connected to both of the network interfaces 13 and 14, reflection occurs from any of the network interfaces 13 and 14, and therefore the reflection recognition circuit 11 causes the network recognition of the network interface 13 and 14.
It is determined that the transmission path is not connected to 14, and data transmission cannot be performed.

If any of the network interfaces 13 and 14 is connected to the transmission lines 15 and 16 that can communicate with each other, the transmission line 15 is connected to the transmission line 15 via the network interface 13 that first tried to recognize the reflection. Performs data transmission. Therefore, in the present embodiment, since the reflected wave of the transmission data generated when the transmission medium is not connected to the network interface is recognized and the presence or absence of the connection of the communicable transmission line is determined, the switching by the manual switch or the like is performed. A physical obstacle such as an error or a contact failure inside the switch is prevented, an accurate transmission medium can be selected, and accurate data transmission becomes possible.

In the present embodiment, the case where there are two network interfaces has been described, but the present invention is not limited to this, and even when there are a plurality of network interfaces, recognition of reflected waves is performed as in the above embodiments. It can be performed. Further, in the present invention, when the reflection cannot be recognized from any of the network interfaces, the default transmission path can be arbitrarily determined.

[0016]

As described above, in the present invention, the selecting means selects the predetermined transmission medium capable of communication from the transmission media corresponding to a plurality of different networks, and selects the predetermined transmission medium and the terminal device. In the transmission medium selecting method for connecting, the reflection recognizing unit recognizes the reflected wave of the data transmitted to the transmission medium connected to the terminal device, and controls the selecting unit according to the recognition of the reflected wave to control the selecting unit. Since the transmission medium connected to the terminal device is changed, it is possible to reliably switch to the predetermined transmission medium with which communication is possible and to connect the predetermined transmission medium and the terminal device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an apparatus using a transmission medium selection method according to the present invention.

[Explanation of symbols]

 11 reflection recognition circuit 12 transmission path selector 13, 14 network interface 15, 16 transmission path (transmission medium)

Claims (1)

[Claims] 1. A transmission medium selection method, wherein a selection means selects a predetermined transmission medium capable of communication from transmission media corresponding to a plurality of different networks, and connects the predetermined transmission medium and the terminal device. The reflection recognition means recognizes the reflected wave of the data transmitted to the transmission medium connected to the terminal, and controls the selection means according to the recognition of the reflected wave to change the transmission medium connected to the terminal device. A method for selecting a transmission medium, characterized in that