JPH02195750A - Time slot busy control method - Google Patents

Abstract

PURPOSE:To perform reception by terminal equipment other than busy terminal equipment by stopping a busy signal outputted from communication equipment corresponding to the busy terminal for prescribed time when the busy terminal equipment exists in the case of performing multi-address communication. CONSTITUTION:In the case of performing the multi-address communication from transmission terminal equipment 41 to the terminal equipment 42 and 43, data from the equipment 41 is outputted to the time slot of a time division multiplex transmission line 5 by a transmission communication terminal 21 via a transmission line 91, and simul taneously, a transmission timer is started up. At this time, when the equipment 43 is busy, communication equipment 23 outputs the busy signal to a busy line 6, and simultaneously, starts up a busy monitoring timer. The terminal 21 performs the re-transmission of transmis sion data with a prescribed time interval, however, equipment 22 and 23 destroy reception data while the busy signal exists. When the busy state of the equipment 43 continues and the time-up of the busy monitoring timer of the equipment 23 is performed first, a controller 1 cancels the sending of the busy signal by the equipment 23 compulsorily. In such a way, the reception can be performed by the terminal equipment other than the busy terminal equipment.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a busy management method for time slots in a 1-hourly segmented transmission line, and particularly to a method for managing the busyness of time slots in a 1-hourly segmented transmission line, and in particular, to enable broadcast communication even when a busy terminal device is present. This invention relates to a busy management method for time slots.

[Conventional technology]

A data transmission system that transmits and receives data between multiple terminal devices using a time division multiplex transmission line is disclosed in Japanese Patent Laid-Open No. 62-278.
As shown in 831, each terminal device is connected to a transmission path via a communication device, the transmitted and received data is temporarily stored in a storage device within the communication device, and the device is connected to this storage device on a time division multiplex transmission path. It is configured to exchange data with the time slot. With this configuration, data transmission and reception is not restricted by the operating speed of the terminal device, and data can be transmitted using continuous time slots.

[Problem to be solved by the invention]

When a terminal device is busy, transmission to that terminal device cannot be performed. Therefore, when attempting to perform a broadcast communication that sends data to multiple terminal devices at the same time, if one of the receiving terminal devices is busy, the transmission becomes impossible, and the broadcast communication to other free terminal devices cannot be performed. The problem was that there was no.

SUMMARY OF THE INVENTION An object of the present invention is to provide a time slot busy management method in a data transmission system using a 1-time division multiplex transmission path, which enables relay communication to other terminal devices even if a terminal device is in a busy state. There is something to do.

[Means for Solving the Problems] The above object is to provide a data transmission system using a time division multiplex transmission path, in which a busy line connecting each communication device, a send a timer for each communication device, and a time shorter than the timer. In addition to providing a busy monitoring timer with a setting of While there is a busy signal on the busy line, data transmission is repeated at predetermined time intervals, and the terminal receives the transmitted data! When there is a busy terminal device in l1ff, the communication device corresponding to the terminal device starts a busy monitoring timer within itself, outputs a busy signal until the timer counts up, and then transmits the above transmission data. This is achieved by making all communication devices compatible with receiving terminal devices discard received data while a busy signal is present on the busy line.

(Function) Since the transmission timer is set for a longer time than the busy monitoring timer, when there is a busy terminal device, the busy monitoring timer of the corresponding communication device times up before the transmission timer. Therefore, after this time-up, the busy signal is stopped and the transmission is retransmitted, so that the retransmission at this time allows the transmitted data to be received by a terminal device other than the busy terminal device.

〔Example〕

The present invention will be explained in detail below using examples. FIG. 1 shows an example of a transmission system to which the method of the present invention is applied, in which a time division multiplex transmission line 5 is connected to a controller 1 for creating time slots and communication bags @ 21 to 23. Terminal devices 41 to 43 are connected to the devices 21 to 23 via transmission lines 91 to 93, respectively. A busy IX6, which is a feature of the present invention, is added between each communication device.

Furthermore, each terminal device is provided with a transmission timer (set time M) and a busy monitoring timer (set time N) (only the timers necessary for the following explanation are shown in the figure).Here, the two set times are It is assumed that there is a relationship of N<M. Time-up signals 71 to 73 of the busy monitoring timer are connected to the controller 1.

The reset signals 81-83 from the controller l are connected to the reset power of each communication device 21-23.

The overall operation of this embodiment is as follows. Now, it is assumed that broadcast communication is performed from the transmitting terminal device 41 to two other terminal devices 42 and 43. Data from the transmitting terminal device 41 is output from the transmitting side communication device 21 to the time slot of the time division multiplexing transmission path 5 via the transmission path 91, and at the same time, the transmission timer is activated. If the receiving terminal device 43 is busy at this time, the communication device 23 outputs a busy signal to the busy line 6 and at the same time activates the busy monitoring timer. The communication devices 22, 23 discard received data while there is a busy signal from the communication device 22,23. On the other hand, the sending side communication device i21
If this busy signal is present and before the transmission timer times up, the transmission data is retransmitted. Therefore, if the receiving terminal device 43 continues to be busy, the busy monitoring timer of one communication device 23 times up first, and the time-up signal 7
3 is sent to controller 1. When the controller 1 detects the time-up of the busy monitoring timer, it forcibly cancels the transmission of the busy signal from the communication device 23 using the reset signal 83, and as a result, the transmission data is transmitted to the communication device 22 by retransmission before the time-up of the transmission timer of the communication device 21. It can be transmitted to the receiving terminal device 42 via.

The details of each part will be explained below. FIG. 2 shows the data structure on the time division multiplex transmission path. One frame is composed of 32 time slots, and one time slot is composed of TA data indicating the transmitting communication device, LA data indicating the receiving communication device (in the figure, there are multiple pieces, indicating broadcast communication), and 100 bytes of data. Ru. These data are output by TA clock 10, LA clock 11, data clock 12 and end clock 14.

FIG. 3 is a block diagram showing an embodiment of one communication device 21 (others having the same configuration), in which each clock 10, 11, 12, 14 . The busy signal 6 and the reset signal 81 are input, the time-up signal 71 is output, and data is exchanged between the transmission path 5 and the terminal device 41. The main components are TA and 1, A comparison circuits 16 and 17
, address setter 15, receiving FIFO memory 211,
Transmission FIFO memory 212. DI circuit 231, microprocessor 24, memory 25. They are a DO circuit 27 and a communication control device 126 (Ilo).

FIG. 4 is a block diagram showing an example of the configuration of the controller 1.
Oscillation circuit 37, clock generation circuit 38, microprocessor 31, memory 34. DI circuit 32 and DO circuit 33
It consists of

Next, the operation of each of these devices will be explained with reference to the flowcharts shown in FIGS. 5 to 7. Data from the transmitting terminal device 41 is stored in the memory 25 via the communication control device 26 and the bus 28 in the communication device 21 shown in FIG. The microprocessor 24 inputs LA to this data as shown in FIG.
Adding data (step 501), sending FIFO
Store in the memory 212 (step 502), memory 25
Clear the transmission retry counter (transmission timer) in (step 503). Once the transmission retry counter is cleared, it starts. When the transmission data is stored in the transmission FIFO memory 212, the output ready signal OR is turned on, and this is the D of the transmission DT flip-flop 202.
Applied to the terminal. After this state is reached, when the TA comparison circuit 16 confirms at the timing of the TA clock 10 that the TA data indicating the transmitting communication device in the data 13 matches the address set in the address setter 15,
The output of the comparison circuit 16 causes the transmission flip-flop 202
is set, and this 111'' output opens the AND gate 192 and the LA clock 11 and data clock 1
2 is applied to the shift-out terminal of the FIFO memory 212, and the LA data and data set in the memory 212 are sent to the transmission line 5 as a signal 13. The end signal 14 is sent to the microprocessor 2 via an AND gate 194.
4 as the transmission end signal 30, the transmission DT flip-flop 202 is reset. This transmission end interrupt signal 30 causes the microprocessor 24 to
The process is performed according to the flowchart shown in FIG. 6, that is, the DI circuit 32 is checked and if a busy signal is input from the busy line (steps 601 and 602), the process continues until the transmission retry counter exceeds M (this causes the set time M), the same transmission data is sent to FIFO 2
12, the output to the time slot is continued (steps 603 to 605). During this time, if the end signal 14 is not input, the transmission retry counter (transmission timer) exceeds M, a time-up signal is output from the DO circuit 27 to the controller 1, and the transmission ends in failure (step 606).

On the other hand, in the communication device 23 on the receiving side, when the receiving FIFO memory 211 is empty, the output OR is "O". Therefore, by using the LA clock 11, L
A match comparison between the A data and the address set in the address setter 15 is performed by the LA comparison circuit 17, and when a match is made, this output causes the 140 of the DT flip-flop 201 to be
19 is not output, therefore the AND gate 191 connected to the shift-in terminal SI of the receive FIFO memory 211 passes the data clock 12 and the data signal 13 is stored in the memory 211. Thereafter, the end signal 14 outputs the reception interrupt signal 29 to the microprocessor 24 via the AND gate 193, and at the same time, the DT flip-flop 201 is set and the LA comparison circuit 17 is reset. In response to the reception interrupt signal 29, the microprocessor 24 performs processing according to the flowchart shown in FIG.

In this process, if the receiving end floor bag w143 is busy,
The microprocessor 24 recognizes this busy state based on the status information of the communication control device 26 and performs steps 701 and 7.
02), by simply incrementing the reception retry counter, which is a busy monitoring timer in the memory 25 (step 709).
), the data stored in the reception FIFO memory 211 is not read out.

As a result, the next time the LA comparison circuit 17 matches.

OR indicating that there is data stored in the reception FIFO memory 211
is output, so the DT flip-flop 201 “
A 0'' output is output, inverted by the oven collector 22, and wired-ORed to the busy signal.

If the receiving terminal device 43 continues to be busy.

Since the same transmission data is retransmitted from the communication device 21, the microprocessor 24 continues to increment the reception retry counter, and when this repetition exceeds N times (step 708), the time-up signal 73 is sent to the Do circuit 27.
Step 710), this is controller 1
The signal is input to the DI circuit 32 (FIG. 4) in the microprocessor 31, and becomes an interrupt signal 36 to the microprocessor 31. This interrupt causes the microprocessor 31 to
Time-up signal 73 from I circuit 32 via bus 35
Step 801) to read out the communication device 23 that has caused the time-up step 802), and set the reset signal 83 to the Do circuit 33 (step 80).
3), this causes the microprocessor 2 of the communication device 23 to
4 is reset (corresponding to 81 in Figure 3) and the communication device is turned off! 23 is reset, and the OR indicating that there is data stored in the reception FIFO memory 211 is no longer output. Since the communication device 23 is no longer busy in this way, the transmitting side communication device 21 can finish transmitting to the time slot before the transmission retry counter exceeds M times.

Since the terminal device 42 is not busy, the communication device 22 proceeds from step 702 to 703 in FIG. 7, reads the DI circuit 231 (step 703), and checks whether a busy signal is input from the busy line 6. (Step 704), if there is a busy signal, the reception FIFO memory 211 is cleared (Step 706), the reception retry counter is also cleared (Step 707), and the reception process is ended. If there is no busy signal, receive data from the receiving FI
It is read from the FO memory 211 and sent to the communication control device 2.
6 to the terminal device 42 (step 705), and clears the reception retry counter (step 707).

〔Effect of the invention〕

According to the present invention, data is received while the receiving side communication device reflects the busyness of the connected terminal device in the busy signal of the time division multiplex transmission path, so data communication can be performed in accordance with the busy state of the terminal device. Therefore, when broadcasting to two or more receiving side communication devices, even if there is a busy terminal device, the receiving side communication device connected to this terminal device can be released from the busy state, so that it is not busy. This has the advantage of being able to carry out broadcast communications to terminal devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a transmission system to which the method of the present invention is applied, FIG. 2 is a diagram showing the data structure on a time division multiplex transmission path, and FIGS. 3 and 4 are diagrams showing a communication device and a controller. A block diagram showing an embodiment, FIGS. 5 and 6 are flowcharts of transmission processing in the communication side communication device, FIG. 7 is a flowchart of reception processing in the reception side communication device, and FIG. 8 is a flowchart of interrupt processing in the controller. It is. 1... Controller, 5... Transmission line, 6... Busy line. 21-23... Communication device, 41-43... Terminal device, 71-73... Time-up signal, 81-83... Reset signal. tree 10

Claims (1)

[Claims] 1. Data when the terminal device is busy in a data transmission system in which each terminal device is connected via a communication device corresponding to the terminal device to a transmission line that performs time division multiplex transmission using time slots. In a time slot busy management method for managing transmission, a busy line connecting each communication device, a transmission timer for each communication device, and a busy management timer set to a shorter time than the timer are provided, and transmission is performed. A communication device compatible with a terminal device activates a transmission timer within itself at the same time as starting data transmission, and repeats data transmission at a predetermined time interval if there is a busy signal on the busy line until the timer times out. If there is a busy terminal among the terminals that are the destination of the above transmission data, the communication device that supports the busy terminal starts its own busy monitoring timer and checks whether the timer counts up or not. A busy signal is output to the busy line until the device becomes busy, and all communication devices compatible with receiving terminal devices that receive the transmitted data receive the busy signal while the busy signal is present on the busy line. A time slot busy management method characterized in that data is discarded and the received data is sent to a corresponding terminal device after the busy signal disappears.