JPH01240042A - Local area network system - Google Patents

Abstract

PURPOSE:To facilitate the transmission path acquisition of terminal equipment by dividing the terminal equipment into groups in the local area network of a CSMA system and mutually connecting the groups when a transmission request is executed to other group. CONSTITUTION:Terminal equipment having a means to execute the transmission of an own device are divided into an A group 1 which is plural groups and a B group 2 when none of other terminal equipment belonging to a same system is in a transmission condition and a cable 3' to mutually connect the terminal equipment in each group is provided. When an access from the A group 1 to the B group 2 is generated, a buffer circuit 8 is made into a closed condition. Serial data are converted into parallel data through a signal line 9 by a converter 4, recognize as an access to the B group with a decoder circuit 5, make a buffer switch 7 open the buffer circuit 8, simultaneously the start instruction of a counting for a specific time is given to a timer 6, the buffer circuit 8 is opened during a timer counting and a network similar to the network of the CSMA system with which (m + n) units are connected regardless of the group is made.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to CS MA (Carrier 5ens
e. Multiple Access) type local area network. In particular, the present invention relates to means for alleviating transmission start waiting time.

〔overview〕

The present invention facilitates the acquisition of transmission paths for terminal devices in a C3MA type local area network by dividing terminal devices into groups (1) and connecting the groups to each other when there is a transmission request to another group. It was designed so that it could be done.

[Conventional technology]

In the conventional method, when data is transferred between multiple terminals on a network to which the terminals are connected, the data transfer is started after confirming that no data is being transferred between other terminals.

[Problem that the invention seeks to solve]

Such conventional methods have the disadvantage that when the line usage rate increases, it becomes difficult for the terminal to acquire a transmission path, resulting in frequent retransmissions, and in the worst case, it becomes impossible to acquire a transmission path.

The present invention aims to eliminate such drawbacks and provides a local area network system equipped with means for facilitating acquisition of a transmission path by a terminal.

[Means for solving problems]

The present invention provides a local area network system including a plurality of terminal devices that perform transmission when other terminal devices belonging to the same system are not in a transmitting state.
The plurality of terminal devices described above are divided into a plurality of groups, and a cable is provided to connect the terminal devices in each group to each other, and a cable that connects the plurality of groups and a cable that is inserted into this cable and formed by this cable are provided. an opening/closing means for opening or closing a route, a detecting means for detecting that a transmission request has been issued from a terminal device in one group to a terminal device in the other group, The present invention is characterized by comprising a control means for giving a command to the opening/closing means to close the path formed by the cable for a predetermined period of time.

[Effect]

Acquisition of transmission paths for terminal devices within a group is performed independently for each group. This inter-group transmission path is connected when a transmission request is made to a terminal device outside the group. This makes it possible to alleviate the phenomenon in which it becomes difficult to acquire a transmission path.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. The figure is a block configuration diagram showing the configuration of this embodiment.

As shown in the figure, this embodiment includes an A group 1 consisting of n terminal devices IA to nA, and an m terminal device IB.
A cable 3 that connects B group 2 consisting of mB to mB, A group 1 and B group 2, a converter 4 that converts serial data on the cable to parallel data, and a buffer that connects and connects the cable between the groups. A circuit 8, a decoder circuit 5 that outputs a control signal to the buffer circuit 8 and a control signal instructing the timer 6 to start counting only when accessing from the own group to another group, and a start of time counting from the decoder circuit 5. A timer 6 receives a signal and outputs a signal to close the buffer circuit 8 after a certain period of time, and the buffer circuit 8 is opened and closed by a signal from the decoder circuit 5 to open the buffer circuit 8 and a signal from the timer 6 to close the buffer circuit 8. A buffer switch 7 is provided. Here, a signal that is connected to the decoder circuit 5 after converting the serial data on the A group l side into parallel data by the converter 4 passes through the signal line 9, and the signal line 10
A signal that is connected to the decoder circuit 5 after converting the serial data on the B group 2 side to parallel data by the converter 4 passes through the signal line 11, and the signal that is connected to the decoder circuit 5 when there is access to a group other than the own group is passed through the signal line 11. A control signal that causes the buffer circuit 8 to be opened is passed through the signal line 12, and a signal that causes the timer 6 to start counting at the same time as the buffer circuit 8 is opened is passed through the signal line 13. After the elapse of time, a control signal for closing the buffer circuit 8 is passed to the buffer switch 7, and a signal for controlling the buffer circuit 8 from the buffer switch 7 is passed to the signal line 14.

That is, in this embodiment, terminal bags WIA-nA and IB to mB, which have means for transmitting their own device when other terminal devices belonging to the same system are not in a transmitting state, are grouped into a plurality of groups A groups 1 and B. Cable 3 that divides into groups 2 and connects terminal devices in each group to each other
', a cable 3 that connects the plurality of groups, a buffer circuit 8 that is inserted into this cable and is an opening/closing means for opening or closing the path formed by this cable, and a terminal of one group. A path formed by a converter 4 and a decoder circuit 5, which are detection means for detecting that a transmission request has been issued from the device to a terminal device in the other group, and a cable 3 based on the output of this detection means for a predetermined period of time. It is provided with a timer 6 and a buffer switch 7, which are control means for giving a command to the opening/closing means to close the opening/closing means.

Next, the operation of this embodiment will be explained based on the drawings.

It is assumed that when an access from A group 1 to B group 2 occurs, the buffer circuit 8 is in a closed state. first,
The serial data passing through the signal line 9 is converted into parallel data by the converter 4. The converted parallel data is sent to the LU by the decoder circuit 5 for access to B group 2.
m, causes the buffer switch 7 to open the buffer circuit 8, and at the same time issues an instruction to the timer 6 to start counting for a certain period of time. Without (m-4
-n) The network becomes similar to the C3MA network in which the devices are connected. When the timer 6 issues a signal to the buffer switch 7 to close the buffer circuit 8 after counting for a certain period of time, the network is switched to only one within each group. However, immediately after the buffer circuit 8 opens or immediately after the timer count ends, the transmitted data may be destroyed, but in that case, retransmission processing is performed.

〔Effect of the invention〕

As explained above, the present invention groups two or more terminals that frequently exchange data, and provides a buffer circuit between the groups to logically disconnect cables.
Even if the usage rate of the transmission line becomes high within one group, the waiting time for starting transmission within the group can be reduced without interfering with other groups' right to acquire the transmission line.

[Brief explanation of the drawing]

The figure is a block configuration diagram showing the configuration of an embodiment of the present invention. 1...A group, 2...B group, 3.3'.
... Cable, 4... Converter, 5... Decoder circuit, 6... Timer, 7... Buffer switch, Death... Buffer circuit, 9.10.11.12.13.14.・・・
Signal line.

Claims (1)

[Claims] 1. In a local area network system including a plurality of terminal devices having means for transmitting the own device when other terminal devices belonging to the same system are not in a transmitting state, A cable (3') that divides into multiple groups and interconnects terminal devices in each group.
), a cable (3) connecting the plurality of groups, an opening/closing means (8) inserted into this cable to open or close the path formed by this cable, and a terminal of one group. Detection means (4) for detecting that a transmission request is issued from the device to the terminal device of the other group.
, 5), and control means (6, 7) for giving a command to the opening/closing means to close the route formed by the cable for a predetermined period of time based on the output of the detection means. Local area network method.