JP2630675B2 - Message relay device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a message relay device, and more particularly to a terminal network control device used for telemetering and the like and a communication port for expanding a communication port in a tree shape. The present invention relates to a message relay device used for a device.

2. Description of the Related Art There is known a data communication system that communicates from a center device to a terminal device such as a meter device or a security device using a telephone line equipped with a no-ringing trunk. Next, a configuration and a communication method of a data communication system as a background of the related art and the invention will be described with reference to FIG.

The center device 20 includes a host computer 1 and a center-side network control device 2. The center side network control device 2
It is connected to the central exchange 3 via a telephone line 11.

On the other hand, the terminal device 30 is a terminal network control device (hereinafter referred to as T-
NCU) 6, a terminal device 7 such as a meter device or a security device, and a home telephone 8.

The T-NCU is connected to the terminal-side switching center 4 via the telephone line 13. The terminal-side exchange 4 has interface lines 15 and 16
Is connected to the no-ringing trunk 5 via the. The terminal-side switching center 4 and the center-side switching center 3 are connected via an interoffice trunk line 12.

In the data communication system shown in FIG. 11, no-ringing communication from center device 20 to terminal device 30 is performed as follows. When the center-side network control device 2 transmits a downlink message such as a command message to the T-NCU 6 by the no-ringing communication, the terminal-side switching center 4 responds to the call from the center-side network control device 2 by the interface lines 15 and 1.
The ringing trunk 5 connected by 6 is called once and secured. The no-ringing trunk 5 selects the telephone line 13 to which the terminal-side device 7 is connected, inverts the polarity of the telephone line 13 at a predetermined cycle, transmits a call signal of a PB signal, and activates the home telephone 8. Without T-NCU6
Call. In this way, when the link is established, the downlink message transmitted from the center-side network controller 2 once
It is received by the T-NCU 6 and its type is determined.

Here, the downlink message includes a message to be received and decoded by the T-NCU 6 for controlling the flow of data in the data communication system (hereinafter, referred to as a decryption message) and a message to be transmitted to the terminal device 7 as it is. (Hereinafter, referred to as a through message). The applicant of the present application filed Japanese Patent Application
In the application of 4457, it was proposed to determine whether or not the message was a through message by the length of a mark included in the header of the message.

When the T-NCU 6 identifies that the down message is a through message, the down message is transmitted to the terminal device 7. A plurality of terminal devices 7 are connected to the T-NCU 6, and a downstream message is transmitted to a specific terminal device according to a destination code (port selection code) included therein.
As described above, the T-NCU 6 has a function of passing a message from a higher-level device to a specified lower-level port connected to a plurality of devices.

By the way, there is the following method as a method of passing a message by specifying a port.

In the first method, a downstream message is divided into a message for designating a lower port and a message containing instruction contents, and a message for designating a lower port is transmitted first. This is a method of sending a message containing the contents of a command after completion.

In the second method, data including port designation data and command contents is included in one message, the message is temporarily stored in a memory, and port designation and activation are performed based on the port designation data. In this method, data including the contents of instructions and the like are read out and transmitted to a designated port.

[Problem to be Solved by the Invention] In the above-described first method, a message for designating a port is transmitted, a response is waited for, and after receiving the response, a message such as the content of the command is transmitted, which is necessary for communication. There is a problem that time is long.

Further, in the second method, since the telegram must be temporarily stored in the memory, the length of the telegram is limited by the capacity of the memory, and the transmission of the telegram is delayed by the time stored in the memory. There is a problem that it is not possible to pass through in real time.

Furthermore, as described above, the method of determining whether or not a message is a through message based on the length of a mark has a problem that reliability is not very high.

Therefore, an object of the present invention is to provide a highly reliable message relay device that does not need to exchange messages for designating a port and allows a downstream message to be passed in real time regardless of the length of the message. To provide.

[Means for Solving the Problems] The present invention is a message relay device used in a device having a plurality of communication ports and having a function of passing a message from one of the ports to another port. According to the present invention, as input messages to be passed, control data having information indicating that the message is a message to be passed and information designating a port to be passed, and a start signal to the port to be passed which is located after the control data A message including dummy data corresponding to the required transmission time and data located after the dummy data and to be passed through is used. The message relay device of the present invention, when receiving a message, determines whether or not the message is a message to be passed through based on control data included in the message, and determines that the message is a message to be passed through the discriminating means. In this case, a means for transmitting a start signal to the port to be through during reception of the dummy data and transmitting the received data to be passed as it is after the start signal is included.

[Operation] In the present invention, the determination as to whether or not the message is a through message is performed by checking whether or not the control data contains information indicating that the message is a through message. Therefore, it is correctly determined that the down message is a through message.

If the down message is a through message, it is necessary to send a signal for activation to the specified port, but this signal is sent after receiving dummy data sent after the control data. Sometimes done. Then, after the signal for starting, the data to be passed is passed as it is, following the dummy data. Therefore, since there is no need to temporarily store data in the memory for port activation, through data is transmitted in real time.

FIG. 1 is a schematic block diagram showing a configuration of a data communication system to which a message relay device according to an embodiment of the present invention is applied. FIG. 2 is a schematic block diagram showing the configuration of the communication port expansion device shown in FIG.

Next, a configuration of a data communication system to which the message relay device of one embodiment of the present invention is applied will be described with reference to FIG. 1 and FIG.

In the data communication system shown in FIG. 1, a communication port expansion device 9 is provided in a terminal device 30. The communication port expansion device 9 is for expanding a communication port in a tree shape, and is connected between the T-NCU 6 and the terminal device 7. Here, the terminal-side device 7 is, for example, a telegram-type gas meter or a telegram-type water meter that exchanges data in a telegram format. Other configurations are the same as those shown in FIG. 11, and therefore, the same portions are denoted by the same reference characters and description thereof will be omitted.

Referring to FIG. 2, a communication port expansion device 9 as an embodiment of a message relay device of the present invention includes a CPU 901, interfaces 902 and 905, a data memory 903, and a program memory 904. The interface 902 is connected to the T-NCU6 and the CP
This is for exchanging messages with U901. The interface 905 is for exchanging messages between the CPU 901 and the plurality of terminal devices 7. The program memory 904 is a memory that stores an operation program of the CPU 901. The data memory 903 is a memory for temporarily storing data generated by the processing of the CPU 901 and the like.
The CPU 901 performs transmission processing of a message exchanged between the T-NCU 6 and the terminal device 7.

FIG. 3 is a block diagram of the terminal device from the center device 20 shown in FIG.
FIG. 3 is an illustrative view showing a basic format of a message transmitted to 30; This basic message consists of a 150-180 ms mark signal and 100
It consists of a ~ 110ms space signal and the text sandwiched between it, the text consisting of a text start code (STX),
It consists of data and a text end code (ETX). Here, the data is represented by an inverted two-way code.

FIG. 4 is an illustrative view showing a configuration of a through message used in one embodiment of the present invention, and FIG. 5 is an illustrative view showing a more detailed configuration than the through message shown in FIG. The through message shown in FIGS. 4 and 5 is a message transmitted from the center device 20 shown in FIG.

Referring to FIG. 4 and FIG. 5, the text of the through message includes control data to the communication port expansion device, dummy data, and through data to the designated port. The control data to the communication port expansion device is transmitted to the communication port expansion device 9.
, A communication mode selection code for designating whether to pass through or not, and a port selection code used to select a port when the communication mode is the through mode. The port selection code includes a code for selecting an upper port and a code for selecting a lower port. The device code, the communication mode selection code, and the port selection code are composed of the inverted double continuous transmission code as described above. That is, each code is composed of a predetermined character and its inverted character (shown with a bar in FIG. 5).

The dummy data is data for performing time gain for transmitting a mark signal to a designated port. Here, the mark signal is a signal for activating a designated port. Through data is data to be transmitted to a designated port as it is. Note that the dummy data and the through data are also inverted 2 like the control data.
It consists of a continuous transmission code.

FIG. 6 is an illustrative view showing a specific configuration of a meter reading request message transmitted from the center device shown in FIG. 1 to the terminal device. In FIG. 6, after the control data, dummy data for transmitting a mark signal to a designated port is added, and thereafter, data to be passed is added to the designated port.

The device code "5" in the control data is a code assigned to the communication port expansion device 9, the communication mode selection code "B" indicates the through mode, and the lower port selection code "2" is the electronic gas meter. Indicates that is selected. The through data is a meter reading request command. That is, the message shown in FIG. 6 is a message for passing the meter reading request command from the communication port expansion device 9 to the message type gas meter. The control data and the dummy data are fixed-length data, and the through data is variable-length data.

The communication port expansion device 9 shown in FIG.
When the message shown in FIG. 6 is received from 20, the message shown in FIG. 8 is transmitted to the designated port. In FIG.
The message transmitted from the communication port expansion device 9 to the terminal device includes a mark signal, STX, through data, ETX, and a space signal. Here, the through data is the meter reading request command itself shown in FIG.

FIG. 7 shows timings of the received message shown in FIG. 6 and the transmitted message shown in FIG. 8 in the communication port expansion device 9.

When decoding the control data included in the data stream received from the T-NCU 6 and determining that the communication mode is the through mode, the communication port expansion device 9 transmits to the designated port while receiving the subsequent dummy data. At the timing of the next character “2” (inverted “D” character) after receiving the fixed data “D” in the dummy data, STX is allocated and transmitted to the designated port. From the next received character, the received data is transmitted through until the space signal is received without decoding the signal by the communication port expansion device 9 itself. In the communication port expansion device 9, since the message is not stored in the internal data memory 903, the through message is passed in real time regardless of the message length.

FIG. 9 is a diagram for explaining a communication sequence in a data communication system to which one embodiment of the present invention is applied. Next, a communication sequence according to an embodiment of the present invention will be described with reference to FIGS.

After establishing the telephone line link, the center device 20 executes T-NC
After exchanging the port selection message of the T-NCU 6 with U6, a through message including port selection data is transmitted to the communication port expansion apparatus 9. As a result, real-time communication in the through mode is performed between the center device 20 and the terminal device 7. If it becomes necessary to change the communication port on the terminal side during the communication, a through message including port selection data for selecting a new port may be transmitted, and exchange of the port selection message with the communication port extension device 9 is performed. Is unnecessary.

Next, a case where the port selection data and the through data are separately transmitted will be considered, and a comparison will be made with the above case.

When the data is transmitted separately, as shown in FIG. 10, after the link of the telephone line is established, an exchange of the port selection message of the T-NCU 6 is performed with respect to the T-NCU 6,
After that, the exchange of the port selection message to the communication port expansion device 9 is performed, and then, the center device 20
Real-time communication in the through mode is performed between the terminal device 7 and the terminal device 7. In this case, if the user wants to change the communication port on the terminal side during the communication, the communication must be performed again from the exchange of the port selection message to the communication port expansion device 9, and much time is required for the communication. Take it. On the other hand, as shown in FIG. 9, if port selection data and through data are transmitted in one message,
The exchange of the port selection message with the communication port expansion device 9 can be deleted, and the time required for communication can be shortened.

The message format and the algorithm of the message processing operation in the above-described embodiment are merely examples, and the present invention can be applied to a terminal-side network control device having a plurality of communication ports.

[Effects of the Invention] As described above, according to the present invention, communication of a message for designating a through port, which is conventionally required, is eliminated, so that communication time is saved, and the present invention is provided behind a relay device having a plurality of communication ports. Even when the second and third relay devices are connected, real-time communication in the through mode can be performed between the center and the terminal device without time delay.

Also, unlike the through message discrimination method based on the time measurement of the mark length, it is now determined that the message is a through message by checking whether or not information indicating that the message should be passed is included in the control data. Therefore, the reliability of the system is extremely high.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a configuration of a data communication system to which a message relay device according to one embodiment of the present invention is applied. FIG. 2 is a schematic block diagram showing the configuration of the communication port expansion device shown in FIG. FIG. 3 is an illustrative view showing a basic format of a message transmitted from the center device shown in FIG. 1 to the terminal device. FIG. 4 is an illustrative view showing the configuration of a through message used in one embodiment of the present invention. Fifth
The figure is an illustrative view showing a more detailed configuration of the through message shown in FIG. FIG. 6 is an illustrative view showing a specific configuration of a meter reading request message transmitted from the center device shown in FIG. 1 to the terminal device. FIG. 7 is a diagram for explaining the transmission and reception timing of a message in the communication port expansion apparatus shown in FIG. FIG. 8 is an illustrative view showing the structure of a message transmitted from the communication port expansion apparatus shown in FIG. 1 to the terminal side apparatus. FIG. 9 is a diagram for explaining a communication sequence in a data communication system to which one embodiment of the present invention is applied. FIG. 10 is a diagram showing a comparative example of the communication sequence. FIG. 11 is a schematic block diagram showing a configuration of a conventional data communication system and a background of the present invention. In the figure, 6 is a terminal side network control device, 7 is a terminal side device,
8 is a home telephone, 9 is a communication port expansion device, 30 is a terminal device, 901 is a CPU, 902 and 905 are interfaces, 903 is a data memory, and 904 is a program memory.

Claims (1)

(57) [Claims] 1. A message relay device having a plurality of communication ports and having a function of passing a message from one of the ports to another port, wherein the input message to be passed is a message to be passed. Control data having information indicating that there is and information specifying a port to be through, located after the control data,
Dummy data corresponding to the time required to transmit a start signal to a port to be through, and located after the dummy data;
Using a telegram including data to be passed through, when receiving the telegram, determining means for determining whether or not the telegram should be passed based on the control data; and When it is determined that there is, during the reception of the dummy data, the start signal is sent to a port to be passed through, and after the start signal, sending means for sending the received data to be passed as it is, and A message relay device.