JP2555975B2 - Communication line test method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication line test method between transmission devices facing each other through a communication line, and in particular, an abnormality in the communication line and the transmission device can be detected early. The present invention relates to a communication line test method.

[0002]

2. Description of the Related Art A conventional communication line test system will be described with reference to FIG.

In the figure, when a communication line test is conducted in two transmission devices 100 and 200 facing each other via a communication line, the transmission device 100 serving as a main device communicates via a transmitter 101 when there is no communication. Send test data to the line. Similarly, in the transmission device 200 serving as a slave device, a loopback path is formed between the transmitter 201 and the receiver 202 during no communication, so that the test data sent from the transmission device 100 is looped back inside the transmission device 200. The route returns to the receiver 102 of the transmission device 100.

The transmission device 100, which is the main device, confirms the normality of the communication line by comparing and collating the sent test data with the reception data returned through the transmission device 200 by the comparator circuit 103.

As a method for performing a test by transmitting test data from the main device during the non-communication period, returning the data by the slave device, and comparing the transmitted / received data, Japanese Patent Application Laid-Open No. Hei 4-
45623 is available.

[0006]

The communication line test method according to the conventional technique as described above requires a master-slave relationship between opposing devices, and the test can be performed only from the main device. Further, since the secondary device only unidirectionally folds back, even if a short circuit fault occurs in the communication line, it cannot be identified as long as it is judged from the test result. Therefore, since it is judged to be normal in such a test, it is not possible to detect the failure during the non-communication state in which the test is performed, and the abnormality is detected only after the communication state. . If the main unit cannot receive the loopback test data, it can detect that there is an abnormality, but is the abnormality occurring in the communication line or in the other party's device? There were various problems that it was not possible to immediately isolate the faulty part.

[0007]

The communication line test system according to the present invention solves the above-mentioned problems and can easily confirm the normality of the communication line, and further detects the short-circuit fault of the communication line. It is an object of the present invention to provide a test method that enables easy and early determination of a faulty part.

The communication line test system according to the present invention is a test system for confirming the normality of a communication line between transmission devices facing each other, and each transmission device sends test data to be sent to the opposite transmission device. Each time the test data is received from the opposite data transmission device and the data generating means that is generated, the received test data is compared with the accumulated test data that was previously received and accumulated, and the received test data is updated as accumulated test data. It has a test means composed of a comparison means for accumulating, and a switching means for detecting a state where the communication line is not used and switching the signal transmitting / receiving circuit to the test means.

The comparison means may instruct the data generation means to regularly change the reception test data according to the comparison result and send it as test data to be sent next. .

Further, the communication line test system according to the present invention is
The contents of the test data are numerical values, and the comparison means determines the test result by taking the difference between the numerical value of the reception test data and the numerical value of the accumulated test data. That is, when the difference is a predetermined normal value, a predetermined number is added to the reception test data and the result is output to the data generating means as the next transmission test data. When the difference is a predetermined abnormal value, failure information according to the abnormal value is output to the host device. If the difference does not correspond to any of the predetermined normal value and abnormal value or if the test data cannot be received within a predetermined time, the accumulated test data is used as the next sending test data. Output to the generating means.

[0011]

Operation: Opposing transmission devices alternately send and receive numerical data, and each time normal reception is performed, the transmission devices that have received the normal data add a fixed value to the received data and send it back as sending data. That is, if normal, the fixed value (n) is added to each of the own device and the partner device, so the difference between the data received last time and the data received this time is twice the added constant value (2n).
Becomes When the communication line is short-circuited in the middle and returns without going through the partner device, the difference between the previously received data and the currently received data is only a constant value (n) added by the own device. Also,
If the partner device cannot receive the data, the partner device returns the data that was received and accumulated last time, so the partner device sends the data before adding the fixed value (n) ( -N) difference is detected.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a communication line test system according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a transmission device which is an embodiment of a communication line test system according to the present invention. In the figure, 10 is a transmission device that sends test data at the start of a test, which will be described later, and 20 is a transmission device that faces the transmission device 10 via a communication line. Then, in each transmission device, 11 and 21 send the transmission data to So.
Transmitters sent from the ut terminal to the communication line, 12 and 22 receivers that receive the received data from the communication line through the Rin terminal, 13 and 23 transmitter side selector circuits that switch between the transmission data and the test data, and 14 and 24 Is a receiving side selector circuit for switching between received data and test data, 15, 25
Is a timer circuit for detecting a non-communication state, 16 and 26 are comparator circuits for accumulating and comparing received test data, and 17 and 27 are data generating circuits for generating test data.

The transmission devices thus configured face each other via a communication line.

If no communication is performed and the communication line remains in a non-communication state for a certain period of time, the timer circuits 15 and 2 of the respective transmission devices
5 detects this and switches the transmission side selector circuits 13 and 23 and the reception side selector circuits 14 and 24 to circuits on the transmission and reception side of the test data. At this time, since the transmission device 10 is predetermined as the transmission device on the test data transmission start side, the timer circuit 15 instructs the comparator circuit 16 and the data generation circuit 17 to start the transmission of the test data, and faces each other. In the other transmission device 20 on the side that receives the initial test data, the timer circuit 25 notifies the comparator circuit 26 of the preparation for receiving the initial test data.

The data generation circuit 17 of the transmission device 10 sends the preset hexadecimal test data to the transmitter 11 via the transmission selector circuit 13.

This test data is sent from the Sout terminal to the communication line, input from the Rin terminal of the transmission device 20 which is opposite, and input to the comparator circuit 26 via the receiver 22 and the reception side selector circuit 24.

Since the comparator circuit 26 has received the initial test data reception preparation notice from the timer circuit 25, the test data received without performing the comparison control on the first received test data. And then
The data generation circuit 27 is instructed to add +1 to the received test data and send it.

The + 1-added test data is sent from the transmission device 20, input to the comparator circuit 16 via the receiver 12 and the reception side selector circuit 14 of the transmission device 10, and accumulated.

When the comparator circuit 16 compares the received test data with the initial transmission test data and confirms that +1 is added, it recognizes that the test path has been established,
Then, the data generating circuit 17 is instructed to send the test data obtained by adding +1 to the received test data.

Thereafter, in the transmission device 10 and the transmission device 20, the mutually received test data is compared with the previously received and stored test data, and the difference between the test data indicates that the test result is normal or abnormal. Is detected.

The transmission device 10 recognizes that the test path has been established, and subsequently the received test data is incremented by +1.
When the added test data is transmitted from the data generation circuit 17, in the transmission device 20 that has received the test data, the comparator circuit 26 compares the test data with the test data that was received and accumulated last time. Since the test data has been incremented by 1 in the transmission device 20 since the last reception, and further incremented by 1 in the transmission device 10, if the test data that is incremented by +2 from the previously received test data is received this time. Judge that the test results are normal. The comparator circuit 26, which has determined that the test result is normal,
The received test data is accumulated, and the data generation circuit 27 is instructed to further add +1 to the received test data and send it.

The comparator circuit 16 of the transmission device 10 which has received the test data to which +1 is added in the transmission device 20
Similarly, the previously received test data accumulated and the test data received this time are compared, and the difference is +
If it is confirmed that 2 has been added, it is determined that the test result is good, the received test data is accumulated, and the data generation circuit 17 is instructed to further add 1 to the received test data and send it.

In this way, if the test data is normally received, +1 is added in each transmission device, so the test data returned by the opposite device in the opposite direction is added +2 when compared with the previously received test data. Has been done. The test data is reset to the initial value again when it reaches a preset constant value as a result of continuing the +1 addition.

On the other hand, the comparator circuit of each transmission device cannot receive the test data within a preset time, or the difference between the received test data is-.
If the content is other than 1, 0, +1 or +2, an abnormal connection signal is sent to the data generating circuit to instruct to send the accumulated previously received test data as it is.

Therefore, the comparator circuit compares the test data received this time with the test data received last time, and if the difference is other than +2, the following abnormality can be estimated.

(1) When the difference is "-1" There is a failure such as communication line disconnection on the transmitting side as seen from the own device, and the other device has not received the signal normally, so the other device received the signal last time. A signal (a signal before +1 addition in the partner device) is transmitted.

(2) When the difference is "0" The same signal as the previously received signal is received again due to the failure of the +1 addition function of the own device and the communication line short circuit failure.

(3) When the difference is "+1": The signal to which +1 is added by the device itself is received as it is due to the communication line short circuit fault.

Alternatively, due to a malfunction of the +1 addition function of the partner device, the partner device does not add +1 and the signal returns.

In this way, the comparator circuit analyzes the reception result and, when an abnormality is detected, notifies the host device (not shown) of fault information. In the host device, the failure information is used to control the failure display on an external display device (not shown) and the disconnection of the communication device from the operating system.

The above test is repeated as long as the communication line is in the non-communication state.

[0033]

As described above, according to the communication line test method of the present invention, the test data is alternately transmitted and received from both transmission devices facing each other through the communication line, and the test data is normally received. The test data received last time and the test data received this time can be easily checked to check the normality of the communication line. It has an effect that it is possible to easily and early detect the failure and determine the failure part.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a communication line test system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a communication line test system according to a conventional technique.

[Explanation of symbols]

 10, 20, 100, 200 Transmission device 11, 21, 101, 201 Transmitter 12, 22, 102, 202 Receiver 13, 23 Transmission side selector circuit 14, 24 Reception side selector circuit 15, 25 Timer circuit 16, 26 Comparator Circuit 17, 27 Data generation circuit

Claims (2)

(57) [Claims] 1. A test method for confirming the normality of a communication line between transmission devices facing each other, wherein each of the transmission devices generates data to be sent to the transmission device facing each other, and data generating means for generating the test data. Each time test data is received from the opposite transmission device, the reception test data is compared with the accumulated test data previously received and accumulated, and the test is composed of a comparison means for updating and accumulating the received test data as accumulated test data. Means and a switching means for detecting a state where the communication line is not used and switching the signal transmitting / receiving circuit to the testing means, wherein the comparing means regularly changes the reception test data according to a comparison result. Then, a communication line test system is instructed to instruct the data generating means to transmit as test data to be transmitted next. 2. The content of the test data is a numerical value, and the comparing means takes a difference between the numerical value of the reception test data and the numerical value of the accumulated test data, and the difference is a predetermined normal value. In addition, a certain number is added to the reception test data and output as the next transmission test data.If the difference is a predetermined abnormal value, fault information corresponding to the abnormal value is output and the difference is When neither the normal value nor the abnormal value set in advance is applicable or when the test data cannot be received within a predetermined fixed time, the accumulated test data is output as the next sending test data. The communication line test system according to claim 1, characterized in that