JPS6395751A - Data transmission system - Google Patents

Abstract

PURPOSE:To contrive to quicken data transmission by sending a data block to one of terminal equipment connected to a low-order depending on the quantity of the comparison result between a destination address in a data block sent from the terminal equipment connected to the high-order and the address of its own equipment from each terminal equipment. CONSTITUTION:An arithmetic section 21 fetches a reception data block and when the data are the data from a terminal equipment connected to the low- order, the control to send the data block to the terminal equipment connected as it is to the high-order is applied. When the reception data block is a terminal equipment connected to the high-order side, the destination address in the data block and the address of its own terminal equipment are compared. Whether the address is addressed to its own terminal equipment or any terminal equipment of two sets of the terminal equipments connected to the low-order side is discriminated to apply control command of a gate to a gate control section 22. Moreover, the arithmetic section 21 applies the control such as interruption inhibition and permission to a channel 20 attended with the reception and relay of the data block.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a data transmission system, and in particular, to a data transmission system having a network configuration suitable for facilitating and increasing the efficiency of data transmission management. to view.

[Prior art]

Conventionally, when connecting a large number of terminal devices to form a data transmission network, a star-shaped, net-shaped, loop-shaped, tree-shaped, bus-shaped configuration, or a combination of these configurations is used. It's here.

Among these, as a prior art related to a data transmission system using a tree-type network, for example,
A technique described in Japanese Patent No. 138239 is known.

This conventional technology is excellent in that it is possible to construct a highly scalable and highly reliable data transmission system by providing each relay terminal in a tree-shaped network with a simple relay function.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional technology requires an address table in the relay terminal device in the tree-type network, and also requires a tree coupler in addition to the terminal function, resulting in a complicated system configuration, making the entire system expensive. There is a problem.

An object of the present invention is to solve the problems in the prior art, and to create an address table in a relay terminal device! - It is an object of the present invention to provide a data transmission system that can reduce the cost of the system by eliminating the need for a coupler and also increase the speed of data transmission.

[Means for solving problems]

According to the present invention, the object is to provide a communication management device that is connected to two downlink channels and has communication relay, control, and management functions, one uplink channel, and one or two downlink channels. By connecting a plurality of terminal devices connected to the network and equipped with communication relay and control functions, the down channel of the upper device and the up channel of the lower device,
This is achieved by configuring a tree-like network in which branches are connected one after another from a higher-level device to a lower-level device, and by assigning addresses to the communication management device and each terminal based on the two-branch theory. And in the network,
Each channel is capable of full-duplex communication, and a terminal device that receives a data block from a lower-level terminal device transmits the data block as is to a higher-level terminal device, and a terminal device that receives a data block from a higher-level terminal device teeth,
The data block is configured to compare the transmission destination address in the data block with the own terminal device address and transmit the data block to the lower terminal device to which it should be transmitted, and furthermore, the two terminal devices in the network communicate with each other. While doing
It is controlled not to accept other communication requests.

[For production]

When a terminal device with the medium Ia function detects a transmission request signal from the terminal bag 7 by interrupt, if it is in a state where data can be received, interrupts from other channels are prohibited thL, and the terminal device that issued the transmission request can receive the signal. After sending a signal, a data block is received.

The terminal device that has received the data block determines the destination terminal device to which the data block is to be sent, transmits a transmission request signal to the terminal device, detects a receivable signal from the other end device, and then sends the data block. to disable interrupts on the channel.

Such operations can be performed in parallel even in other bifurcated terminal devices using channels capable of duplex communication, making it possible to parallelize data transmission. Also,
The two-branch search method does not require operations such as referring to an address table, and data can be transmitted at high speed.

〔Example〕

Hereinafter, one embodiment of the data transmission system according to the present invention will be described in detail with reference to the drawings.

Figure 1 is a network configuration diagram of a two-branch data transmission system, Figure 2 is a configuration diagram of transmission data blocks, Figure 3 is a block diagram of terminal device relay and control unit, and Figure 4 explains transmission operation. 5 is a flowchart for explaining the receiving operation, FIG. 6 is a timing diagram for the transmitting operation, and FIG. 7 is a diagram showing the transition when a conflict occurs in the terminal device. In Figures 1 to 3, 1 to 6.8
- 12 is a terminal device, 7 is a communication management device, 20 is a channel, 21 is an arithmetic unit, 22 is a gate control unit, 23 is a transmitter/receiver unit, 24 is a transmission request line, 25 is a transmission enable line, 26 is a transmission data line, 27 is a received carrier detection line, 2
8 is the receivable line, 29 is the receive data line, S Y
C1, 5Y C2 is a synchronization character, ADD 1 is a transmission destination address, ADD2 is a transmission source address, and DAT is data. Note that the codes assigned to the terminal device and the communication management device simultaneously indicate the address of each device.

As shown in FIG. 1, the network for the data transmission system according to the present invention has the communication management device 7 at the apex of two branches, and a plurality of terminal bags RF! 1-6.8-1
3 is configured in a tree shape in which two branches are connected via a transmission path. The addresses of the communication management device and the terminal devices connected to the lower level are smaller than the address of the communication management device, and the address of the other terminal device is smaller than the address of the communication management device. Similarly to the above, the address of one terminal device connected to the lower level is larger than the address of the terminal device connected to the lower level. It is set so that the address of the other terminal device is larger than the address of the terminal device above it.

Transmission data blocks transmitted within such a network are marked with synchronization characters 5YC1, as shown in FIG.
, transmission destination address ADDI, transmission source address ADD2,
Data DAT and synchronization character 5YC2 are arranged in this order. The synchronization character syc i indicates the beginning of the data block and has the function of synchronizing the timing with the receiving device. The transmission destination address ADD 1 indicates the destination terminal device of the data block, and the transmission source address AD
D2 indicates the source terminal device of the data block. Further, data DAT is data to be sent to the destination terminal device, and synchronization character 5YC2 indicates the end of the data block.

FIG. 3 shows the block configuration of the relay and control unit of the terminal equipment connected in the network. , a gate control section 22, and a transmitting/receiving section 23, which are configured identically, are connected.

The transmitting/receiving unit 23 is connected to a terminal device on the upper side or the lower side via a channel 20 which is a transmission path, and detects a signal from the channel 20 and transmits a signal on the channel 20-1. The channel 20 includes a transmission request line 24, a transmission enable line 25, a transmission data line 26, a carrier detection line 27, a reception enable line 28, and a reception data line 29. When no other terminal is accessing the transmitter/receiver 23, the transmittable line 25 and the received carrier detection line 27 are always set to a low level.

The gate control section 22 controls connection and disconnection between the transmitting/receiving section 23 and the computing section 21 according to instructions from the computing section 21 .

The calculation unit 21 takes in the received data block, and if the data is from a terminal device connected to the lower side,
Control is performed to send the data block as it is to the terminal device connected to the upper side, and if the received data block is from the terminal bag 'J1 connected to the upper side,
The transmission destination address in the data block is compared with the address of the own terminal device, and it is determined whether the transmission is addressed to the own terminal device or to which one of the two terminal devices connected to the lower side. , instructs the gate control unit 22 to control the gate. In addition, the arithmetic unit 21 disables interrupts to the channel 20 and
Control permissions, etc.

Although the terminal device has been explained above, the communication management device 7 is configured in almost the same way as the terminal device. Since there is no device connected to the upper side of the communication management device 7, the terminal device shown in FIG. It is configured by removing the gate control section 22 and the transmitting/receiving section 23 that connect with the upper terminal device from the configuration.

The operation of transmitting a data block in the terminal device or communication management device configured as described above will be explained with reference to the flowchart shown in FIG.

(1) The calculation unit 21 checks whether the destination terminal device is connected (Flow 100).

This checking method is based on the level of the sendable line 25. If the sendable line 25 is at a low level, the calculation unit 21 determines that the destination terminal device is not connected. However, in the case of transmission for relay, an error is sent back to the transmission source (Flow 101).

(2) If the ready-to-send line 25 shows a high level,
The calculation unit 21 assumes that the destination terminal device is connected, and sends f3 to the terminal device via the transmission request line 24.
It sends a request signal, waits for the ready-to-send line 25 to go low, and when the ready-to-send line 25 goes low, it transmits the data block to the destination terminal device (flows 102 to 104).

Next, the data block receiving operation will be explained with reference to the flowchart of FIG.

(1) The calculation unit 21 determines whether or not it is in a state where it can receive a data block from the current location channel, and if it cannot receive it, it prohibits interruptions from other channels (Flow 2
00.201).

(2) If the data block can be received, the calculation unit 21 enables interrupts from other channels and receives (3)
Preparations are made, the carrier on the carrier detection line 27 is monitored, and the carrier is detected (flows 202 and 203).

(3) When a carrier is detected, interrupts from channels other than the channel transmitting the carrier are prohibited, and the receivable line 28 of the channel transmitting the carrier is prohibited.
to low level (on) state (Flow 204.20
5).

(4) After that, receive the incoming data block,
Ready line 28 when all data blocks have been received
to a high level (off) state (Flow 206.20
7).

(5) Check whether the received data block is from a channel connected to a lower-level terminal device, and if it is an upstream data block from a lower-level terminal device, the terminal connected to the higher-level side This data block is transmitted to the device (flows 208 and 213).

(6) If the received data block is a downlink data block from an upper terminal device, the address of the own terminal device and the transmission destination address in the received data block are compared (Flow 209).

(7) As a result of the address comparison in (6) above, if the transmission destination address is smaller than the own terminal device address, in the example of the network shown in Figure 1, the data received by the terminal device connected to the lower side located on the left side When a block is sent and the destination address is larger than the address of the own terminal device,
Sends the received data block to the terminal device connected to the lower side located on the right side (Flow 210.212
).

(8) If the transmission destination address matches the own terminal device address, the received data block is addressed to the own terminal device and is processed within the own terminal device (Flow 211>).

In the above description of the data block receiving operation of the terminal device, the transmitting operation after receiving the data block is performed according to the flowchart of the transmitting operation shown in FIG. 4, as already explained. Each terminal device can transmit, relay, and receive data blocks by transmitting and receiving data blocks as described above, and through this operation, data block transmission is performed from the source terminal device to the communication This is done via a uniquely determined path that passes through the device and reaches the destination terminal.

FIG. 6 shows a timing chart during the transmission operation, and the timing of the sending terminal device's transmission request, detection of a send ready signal, and data block transmission, which have already been explained using the flowchart in FIG. It shows the timing of detecting a receiving carrier, receiving a receivable signal, and receiving a data block at the receiving terminal device.

In the embodiment of the present invention described above, each terminal device is not given a priority order, so all terminals requesting data transmission can perform data transmission according to the above-described operation, and there is no priority between each terminal device. Data transmission can be performed in parallel.

On the other hand, transmission requests may be issued from two or three directions to one terminal device, resulting in contention of transmission requests. The operation of the terminal device in this case will be explained with reference to FIG. 7 showing the transition of the terminal device.

Now, as shown in FIG. 7(a), a certain terminal device has a data block I to be transmitted to the lower left terminal device of the terminal device, and the upper terminal device sends data block I to the lower left terminal device. Assume that there is a request to send data block (2) from the device and data block (2) from the lower right terminal device.

In this case, as shown in FIG. 7(b), the terminal device having the data block I to be transmitted first transmits the data block using the full-duplex communication function of the channel with the lower left terminal device. I and III are transmitted and received simultaneously.

Next, as shown in FIG. 7(c), this terminal device exchanges a data block (2) with the upper terminal device.

A terminal device that performs the transmission/reception described in (2) and in which a conflict of transmission requests has occurred can deal with the conflict by sequentially performing the above-described operations using the full-duplex communication function of the channel.

〔Effect of the invention〕

As explained above, according to the present invention, in a data transmission system using a bifurcated tree-like network,
The transmission path from the transmission source terminal device to the transmission destination terminal device via the communication management device can be determined in ms using a two-branch search power formula without the need for an address table, resulting in a low-cost, high-speed system. A data transmission system can be provided.

[Brief explanation of the drawing]

Figure 1 is a network configuration diagram of a two-branch data transmission system, Figure 2 is a configuration diagram of transmission data blocks, Figure 3 is a block diagram of terminal device relay and control unit, and Figure 4 explains transmission operation. 5 is a flowchart for explaining the receiving operation, FIG. 6 is a timing diagram for the transmitting operation, and FIG. 7 is a diagram showing the transition when a conflict occurs in the terminal device. 1-6, 8-12... Terminal device and its address, 7... Communication management device and its address, 20... Channel , 21
...... Arithmetic section, 22... Gate control section, 23... Transmission/reception section, 24.
......Transmission request line, 25...
...Transmittable line, 26......Transmit data line, 27...Receive carrier detection line, 28...Receiveable line, 29 ...
・・・・・・Reception data line, 5YC1, 5YC2・
・・・・・・Sync character, ADDl・・・・・・
...Transmission destination address, ADD2...
Transmission source address, DAT... Data. Figure 2 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. A communication management device that is equipped with a communication relay, control, and management function and has two downlink channels, and a communication management device that is equipped with a communication relay and control function and has one uplink channel and one or two In a data transmission system having a tree-like network in which multiple terminal devices each having one downstream channel are branched and connected one after another, the address of the communication management device or each terminal device is the address of one of the terminal devices connected below it. The address of each terminal device is set to be larger than the address of the other terminal device, and smaller than the address of the other terminal device. Compare the transmission destination address in the data block sent from the terminal device with the address of the own device, and depending on the size of the comparison result, send the data block to one of the terminal devices connected to the lower side, and perform the comparison. A data transmission system characterized in that when the results match, the data is imported into its own device. 2. Each terminal device transmits the data block received from the terminal device connected to the lower level side as it is to the terminal device or communication management device connected to the higher level side. The data transmission system according to item 1. 3. The communication management device and each terminal device include an arithmetic unit that receives a received data block and a gate control unit that transmits a data block including a destination address to the destination terminal device. The data transmission system according to scope 1 or 2.