JPH04364620A - Monitoring system - Google Patents

Abstract

PURPOSE:To detect the fault of an error checking circuit or the like in which no error can be detected. CONSTITUTION:An error checking bit generating circuit 3 in a transmission side equipment 1 receives a transmission signal 2 and outputs an error checking bit 4. In this case, the error checking bit generating circuit 3 inserts an error periodically to the error checking bit 4 with the control of an error occurrence control circuit 5. A multiplexer circuit 6 multiplexes the transmission signal 2 and the error checking bit 4. A protective circuit 10 at a reception side equipment 7 protects an error checking output 9 detected by an error checking circuit 8 and outputs a fault checking output 11 when the error exceeds a threshold level. When an error checking output 9 is not consecutive for a prescribed time or above, an interrupting detection circuit 12 generates a monitoring function fault detection output 14.

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 telecommunications equipment, and more particularly to a system for monitoring failures in telecommunications equipment that transfers digital signals.

0002

2. Description of the Related Art In a conventional monitoring system, a transmitting device of a transmission device adds an error check bit to a digital transmission signal, and transmits this transmission signal to a receiving device via a transmission path. The receiving device uses error check bits to detect errors in the input transmission signal and applies certain protection to determine whether there is a failure in the transmission device.

0003

[Problem to be Solved by the Invention] This conventional monitoring method only monitors whether errors in the transmission signal are not detected, so if no errors are detected, the question is whether there really is an error or whether the error detection circuit is malfunctioning. The problem was that I didn't know if they were there or not.

0004

[Means for Solving the Problems] The monitoring system of the present invention adds an error check bit to the transmission signal at the transmitting side of the transmission device, and the receiving side uses the error check bit to detect and predetermine errors. In a monitoring method that determines whether or not there is a failure in the transmission device by applying a certain level of protection,
The transmitting side device has means for periodically generating an error in the error check bit at a frequency that does not require protection of the receiving side device, and the receiving side device detects the periodic error in the check bit. and means for monitoring an operation of a failure monitoring function of the transmission device.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention.

[0006] In the transmitting side device 1, an error check bit generation circuit 3 inputs the digital transmission signal 2 and generates error check bits 4 represented by parity and CRC code.
Create and output. At this time, an error is periodically inserted into the error check bit 4 under the control of the error occurrence control circuit 5. The transmission signal 2 and error check bit 4 are multiplexed by a multiplexing circuit 6 and sent to a transmission line 15.

On the other hand, in the receiving side device 7, an error detection circuit 8
The transmission signal input from the transmission line 15 is checked for errors, and if an error is found, an error detection output 9 is output. The protection circuit 10 protects the error detection output 9 by, for example, triple matching, and outputs a fault detection output 11 when the error detection output 9 exceeds this threshold value. The disconnection detection circuit 12 generates a monitoring function failure detection output 14 when the error detection output 9 is not output continuously for a certain period of time or more.

As described above, since errors are periodically inserted into the error check bit 4, the error detection output 9 is output periodically if the error detection circuit 8 is operating normally. Therefore, the error detection output 9 is periodically input to the disconnection detection circuit 12, and the monitoring function failure detection output 14 is not output. If a circuit constituting the transmission device such as the error detection circuit 8 fails and the error detection output 9 is no longer output, the disconnection detection circuit 12 detects the disconnection of the error detection output 9 and activates the error monitoring function. can detect that it is not operating normally. By lowering the frequency of error insertion into the error check bit 4 below the detection threshold of the protection circuit 10, it is possible to prevent the expensive fault detection output 11 from being issued even when there is no fault in the transmission device.

[0009]

As explained above, the present invention provides means for periodically generating errors in error check bits at a frequency that does not require protection of the receiving side device in the transmitting side device of a transmission device; Since a means for monitoring whether errors in unprotected transmission signals are periodically detected is provided, it is possible to detect failures in the error detection circuit or the like where errors in transmission signals are no longer detected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention.

[Explanation of symbols]

1 Transmission side device 2 Transmission signal 3 Error check bit generation circuit 4 Error check bit 5 Error generation control circuit 6 Multiplexing circuit 7 Receiving side device 8 Error detection circuit 9 Error detection output 10 Protection circuit 11 Fault detection output 12 Disconnection detection circuit 13 Transmission signal 14 Monitoring function failure detection output 15 Transmission line

Claims (2)

[Claims] Claim 1: A transmission side device of a transmission device adds an error check bit to a transmission signal, and a reception side device uses the error check bit to detect an error in the transmission signal, In the monitoring method for determining the presence or absence of a failure in the transmission device by applying protection, the sending device includes means for periodically generating an error in the error check bit at a frequency that does not require protection of the receiving device; A monitoring system characterized in that the receiving device includes means for monitoring the operation of the fault monitoring function of the transmitting device by detecting the periodic error in the check bit. 2. A transmitting side device of a transmission device adds an error check bit to a transmission signal, and a receiving side device uses the error check bit to detect an error in the transmitted signal, In the monitoring method that determines the presence or absence of a failure in the transmission device by applying protection, the transmission device includes an error check bit generation circuit that receives a first transmission signal as input, creates and outputs an error check bit, and an error generation control circuit that controls a check bit generation circuit and periodically generates an error in the error tech bit; and multiplexing that multiplexes the first transmission signal and the error check bit into a second transmission signal. The receiving side device has an error detection circuit that detects an error in the second transmission signal input from the transmission path and outputs an error detection output, and an error detection circuit in which the error detection output is a predetermined constant value. A monitoring system comprising: a disconnection detection circuit that outputs a monitoring function failure detection output indicating a failure of the monitoring function of the transmission device when no time input is received.