JPH0969804A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the position of a fault on a cable or the like by providing a non- communication detection part and a fault detection control part at control equipment, transmitting information at the time of no communication and detecting it at the control equipment that there is no response information from communication equipment. SOLUTION: Control equipment 1 always monitors the communication state of the line by using a non-communication detection part 13 and while the state of no communication is detected, an information signal is sent from a fault detection control part 12 through an adder amplifier 11 to a transmission line 21. The sent out signal is received by information transmission control parts 33 at plural base stations 3. The response information is sent out through an adder amplifier 32 to a reception line 22 by the control part 33 at the base station 3 designated by transmission information among the plural base stations. The sent out response information is transmitted through the line 22 to the equipment 1, received and detected by the control part 12. The control part 12 performs information transmission with the respective base stations 3 and displays the base station 3, from which the response information is returned, and the base stations 3 from which no response information is returned. Thus, the cable fault can be detected corresponding to whether the response information is returned or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for monitoring a communication line in a communication system for a failure.

[0002]

2. Description of the Related Art As a conventional technique, there is a system shown in FIG. In FIG. 2, the supervisory signal from the supervisory signal generation circuit (OSC) 14 provided in the control device 1 is the constant summing amplifier 1
1, the transmission line 2 of the connection cable 2 of the communication line
Sent to 1. The sent monitor signal is input to the plurality of base stations 3 connected in series. Each base station 3
Is output to the next stage through the level correction amplifier 31 of the transmission line. In the (N) th base station 3 (N is a positive integer), the signal from the transmission line is loop-connected to the reception line 22, and the (N) th base station 3 and a plurality of base stations 3 and (1 ) -Th base station 3 and is input back to the control device 1. The control device 1 detects the supervisory signal that has been looped back and is detected by the supervisory signal detection circuit 15. As a result, when the supervisory signal disconnection is detected, the fault detection control unit 16 displays that there is a fault in the communication line. .

[0003]

In the above-mentioned prior art,
When a disconnection of a monitoring signal is detected, it is not possible to know which part of the cable between the serially connected base stations is the cable failure. It has the drawback of having to identify and investigate where the cable is failing. It is an object of the present invention to eliminate this drawback so that the location of a cable fault can be easily identified by the information transmission during non-communication.

[0004]

In order to achieve the above object, the present invention detects a non-communication state and constantly transmits information between a control device and a plurality of base stations during non-communication.

As a result, a cable failure point can be detected without conducting a communication test or the like, so that it is possible to monitor the line with good maintenance efficiency.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described below. In FIG. 1, 1 is a control device, 2 is a communication line, 3 is a base station, and 11 is a summing amplifier. Reference numeral 12 denotes a failure detection control unit, which displays a failure location as a result of transmitting information with a plurality of base stations 3. Reference numeral 13 denotes a non-communication detector, which detects the usage status of the communication line. 31, 32
Is a level correction amplifier, of which the level correction amplifier 32 simultaneously adds information transmission signals output from an information transmission control unit 33 described later. An information transmission control unit 33 performs information transmission with the fault detection control unit 12 of the control device 1. Reference numeral 21 is a transmission line, and 22 is a reception line.

Hereinafter, this operation will be described. The control device 1 constantly monitors the communication state of the line by the non-communication detection unit 13, and when the non-communication state is detected, the fault detection control unit 12 transmits the information transmission signal through the addition amplifier 11 to the transmission line of the communication line 2. 21. The transmitted information transmission signal is received by the information transmission control unit 33 of the plurality of base stations 3, and the response information is added from the information transmission control unit 33 of the base station 3 designated by the transmission information among the plurality of base stations. It is sent to the reception line 22 of the communication line 2 through 32. The transmitted response information is transmitted to the control device 1 through the reception line 22, and the failure detection control unit 12 receives and detects it. The failure detection control unit 12 transmits information with each base station 3 and displays the base station 3 to which response information is returned and the base station 3 to which response information is not returned.

By the above operation, the controller 1 controls the base station 3
It is possible to detect a cable failure between the plurality of base stations 3 depending on the presence or absence of response information from.

[0009]

According to the present invention, by transmitting information by utilizing the non-communication time with the base station which cannot transmit information by the control device, a cable failure between the communication devices connected in series can be prevented. Since it is possible to detect the line without lowering the usage efficiency of the line and without performing a communication test, the efficiency of maintenance can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a block configuration example of a communication system according to the present invention.

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

[Explanation of symbols]

 1 control device, 2 communication line, 3 base station, 12 failure detection control unit, 13 non-communication detection unit, 14 supervisory signal generation circuit (OSC), 15 supervisory signal detection circuit, 21 transmission line, 22 reception line, 31, 32 Level correction amplifier, 33 Information transmission control unit.

Claims (1)

[Claims] 1. A communication system having a control device and a plurality of communication devices (base stations) connected in series to the control device, wherein the control device is a non-communication detection circuit (non-communication detection unit).
And a control circuit (fault detection control unit) for performing fault detection control during non-communication, and the plurality of communication devices (base stations) have number information unique to the communication device (base station) with respect to the control device. By providing an information transmission control unit for transmitting the above information, transmitting the above information during non-communication, and detecting by the control device that there is no response information from the communication device, the cable between the plurality of communication devices, etc. A communication system characterized by detecting an obstacle point of the.