JPS63299636A - Data transmission system - Google Patents

Abstract

PURPOSE:To execute an immediate transmission and a large capacity transmission by dividing a frame per transmitting byte number, and adding byte information to indicate the transmitting byte number at the beginning of data to correspond divided respective equipments at the time of requesting communication the respective equipments. CONSTITUTION:The frame of a prescribed byte length is divided by the prescribed transmitting byte number of a data equipment in communicating and byte information (B4-7) to indicate the transmitting byte number are added to the beginning of data (data 4-7) to correspond to a byte-divided equipment. At the beginning of the respective frames, frame information (F1) to show whether the frame is effective or ineffective and byte information (BA) to indicate the byte number of the all effective data in one frame are added. A figure shows a case of the data of data equipments 4, 5 and 6 are transmitted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a data transmission system, and particularly to a data transmission system in which a single data transmission path is used by multiple communication devices with different transmission amounts and transmission speeds for time sharing. Regarding data transmission methods.

[Conventional technology]

Conventionally, time share link technologies for data transmission methods include cyclic methods and packet methods.

In the cyric method, a channel is assigned to each device,
Immediate transmission is always possible if there is a transmission request, and the data transmission speed is standardized, making it highly practical.In contrast, the packet method cannot transmit data until the transmission path is full, or until the maximum capacity is reached. It is possible, and has a much larger effective transmission capacity than the cyclic method at the same transmission speed.

[Problem that the invention seeks to solve]

The cyclic method, which is cited as a technology for the time-share link method of conventional data transmission mentioned above, allocates a predetermined time slot in a frame to each device, and usually each device performs transmission for a short time. In the case of a data transmission system that has multiple devices with different transmission characteristics and transmission speeds,
This results in a system that wastes a lot of transmission time. Also, the packet method has a larger transmission capacity than the cyclic method, but if the transmission path is blocked when a transmission request occurs, there will be a wait until the transmission path becomes free, and immediate transmission will be required. The disadvantage is that it is unsuitable for certain cases.

[Means for solving problems]

The method of the present invention is a data transmission method in which a data transmission path is used for time sharing among a plurality of communication devices whose transmission amount and transmission speed are not all the same. The required data length for the transmission is allocated to the empty portion in the frame having the required data length for transmission by the communication device, and information indicating the required data length for the transmission is added.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. The transmission device 1 and the transmission device 2 perform data transmission through a transmission path 3, and four data devices 4 to 7 that operate at different variable transmission amounts and transmission speeds are connected under the transmission device 1. FIGS. 2(a) and 2(b) are data format diagrams each showing a frame format of transmission data of the transmission device 1 in this embodiment. The frame format in this embodiment is such that a frame of a predetermined byte length is divided by the required number of transmission bytes of the data device in communication, and at the beginning of the byte-divided data (data 4 to 7) corresponding to the device, the number of transmission bytes is It has a configuration in which byte information (B4 to B7) representing . Furthermore, at the beginning of each frame, there is frame information (FI) that indicates whether the frame is valid or invalid, and byte information (BA) that indicates the number of bytes of all valid data within one frame.
). The byte information (BA) displays the total number including the number of transmitted bytes indicated by the device-specific byte information. Figure (a) shows a case where data is transmitted from data devices 4, 5, and 6, and figure (b) shows an example of a case where data device 7 needs to transmit a large amount of data at high speed. In the case of (b>) in the figure, one frame is occupied by data from the data device 7.

〔Effect of the invention〕

As explained above, the present invention provides a channel that is fixedly assigned to each device during a frame when multiple communication devices share one high-speed data transmission path through time sharing and transmit frame-synchronized data. By dividing the 7 frames according to the number of bytes to be transmitted when each device requests communication, and adding byte information representing the number of bytes to be transmitted at the beginning of the divided data for each device, the amount of transmission can be reduced. Immediate transmission and large-capacity transmission are easily possible in a mass data transmission system having multiple communication devices with different speeds.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 (a
) and (b) are data format diagrams showing frame formats in embodiments of the present invention. 1.2... Transmission device, 3... Transmission line, 4-7...
Communication equipment, BA, 84-B7...byte information, FI/
...Frame information.

Claims (1)

[Claims] In a data transmission method in which time sharing is used on a data transmission path by multiple communication devices whose transmission amount and transmission speed are not all the same, an empty portion within a frame having a predetermined data length and format when a transmission request is generated from the communication device. A data transmission method characterized in that the required data length for the transmission is allocated for transmission by the communication device, and information indicating the required data length for transmission is added.