JPH07147564A - Optical connection monitor - Google Patents

Abstract

PURPOSE:To report a fault of optical communication immediately to an opposite party equipment by generating an idle signal specific to an optical interruption state when an optical connection monitor between optical communication equipments connecting to an optical fiber cable detects the optical interruption from the reception state. CONSTITUTION:When a communication control section 13 of an optical transmitter-receiver 1 detects an abnormality of optical communication due to optical interruption, the control section 13 stops the reception and stops the reception from an AUI interface 14 and an internal loopback and sends an idle signal in 2.5MHz specific to the optical interruption in place of an idle signal in 1Hz to an optical signal transmission section 11. The optical signal transmission section 11 sends the idle signal in 2.5MHz indicating the optical interruption to an optical fiber cable 3. An idle signal at the time of optical interruption received by an optical signal reception section 22 of an opposite party optical transmitter-receiver 2 is sent to a communication control section 23, in which the optical interruption detected by an opposite party equipment is recognized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connection monitor applied to optical communication equipment connected by an optical fiber cable.

[0002]

2. Description of the Related Art Conventionally, an optical communication device connected by an optical fiber cable has a function of transmitting an idle signal of 1 MHz to a partner optical transmitter / receiver for setting an idle state, and an optical fiber cable is used. It has an optical connection monitor function at the connection part.

This optical connection monitor function is for normal communication because the optical power level of the optical signal received by the optical signal receiving unit of the optical transmitter / receiver is lower than a predetermined level, due to, for example, an optical fiber cable failure. When it becomes impossible to secure the condition, the abnormality is detected as "light interruption".

The optical disconnection detection by the optical connection monitor function is
When the communication control unit in the own device recognizes that the signal input from the other device is stopped, the own device side senses an abnormality on the other device side. The abnormal state at this time is externally recognized by the device itself by lighting an LED or the like.

At this time, signal input from the AUI interface is stopped, and at the same time, loopback performed by the communication control unit is also stopped. Then, the idle signal of 1 MHz is transmitted to the optical signal receiving section of the optical transmission / reception device on the other side.

As described above, in the conventional optical communication equipment, the idle signal of 1 MHz is transmitted to the other side optical transmitter / receiver in order to set the idle state during the normal transmission / reception, and the optical connection is made. Even under the light interruption detection state by the monitor function, the idle signal of 1 MHz is transmitted to the other side optical transceiver.

Therefore, from the received idle signal,
An optical transmitter / receiver that receives an idle signal cannot immediately recognize whether it is in a normal state or an optical disconnection state due to a failure of the optical fiber cable, and whether the idle signal is an idle signal during normal transmission or reception I cannot grasp whether it is due to a light interruption in the connection monitor function. Therefore, only the optical transmission / reception device on the light interruption reception side (the side that recognizes the light interruption) can recognize the light interruption state, and the occurrence of the light interruption cannot be immediately recognized by the optical transmission / reception apparatus on the other side.

As described above, in the conventional optical communication equipment,
On the optical transceiver side that received the idle signal, whether the received idle signal is an idle signal under normal transmission / reception status, or the optical connection monitor function of the other side optical transceiver has an optical disconnection due to an optical fiber cable failure It is not possible to immediately grasp whether the signal is an idle signal under the condition of detecting the. Therefore, there is a problem that only the optical transmission / reception device on the light interruption reception side (the side that recognizes the light interruption) can recognize the light interruption state, and the other optical transmission / reception device cannot recognize the light interruption.

[0009]

As described above, in the conventional optical communication equipment, in the optical transmitter / receiver side which has received the idle signal, the received idle signal is the idle signal in the normal transmitting / receiving state. Whether it is a signal or an idle signal in a state where the optical connection monitor function of the other side optical transmitter-receiver detects an optical interruption cannot be immediately grasped. Therefore, there is a problem that only the optical transmission / reception device on the light interruption reception side (the side that recognizes the light interruption) can recognize the light interruption state, and the other optical transmission / reception device cannot recognize the light interruption.

The present invention has been made in view of the above circumstances,
In the optical connection monitor between the optical communication devices connected to the optical fiber cable, when the optical disconnection is detected from the received signal state, it has a function to generate an idle signal specific to the optical disconnection and send it to the other device To provide an optical connection monitor capable of promptly notifying a partner device of a communication abnormality at the time of light interruption and easily distinguishing the abnormality of an optical connection portion at the time of light interruption between devices. With the goal.

[0011]

SUMMARY OF THE INVENTION The present invention is an optical connection monitor between optical communication devices connected to an optical fiber cable.
When a light interruption is detected by monitoring the reception state, an idle signal specific to the light interruption is generated and sent to the partner transmission / reception device to immediately notify the communication partner device of the optical communication abnormality. To do.

[0012]

[Operation] In the optical connection monitoring mechanism between the optical communication devices connected to the optical fiber cable, the transmitting / receiving device A
When detecting a light interruption, transmits an idle signal of a frequency different from the idle signal used during normal transmission / reception to the transmission / reception device B of the communication partner. When the transmitter / receiver B receives this signal, the transmitter / receiver B separates it by the communication control unit and recognizes the light interruption state. As a result, each optical transceiver can recognize not only the optical interruption on the receiving side such as the occurrence of a failure of the optical fiber cable, but also the optical interruption on the transmitting side due to the occurrence of the failure of the optical fiber cable to the communication partner. It is easy to identify abnormalities in the optical connection part when the light is cut off.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of an optical communication system by optical fiber cable connection to which the present invention is applied.

In FIG. 1, reference numerals 1 and 2 denote optical transmitter / receivers connected to each other by optical fiber cables 3 and 4, each having an optical signal interface and an electrical signal interface.

Optical fiber cables 3 and 4 connect the optical signal interfaces of the optical transceivers 1 and 2 to each other. Reference numerals 11 to 15 are constituent elements of the optical transmitter / receiver apparatus 1, and 21 to 25 are optical transmitter / receiver apparatus 2 respectively.
Is a component of.

Of these components, reference numerals 11 and 21 denote optical signal transmitters (E / O), which convert electric signals according to the contents of transmission data into optical signals (E / O conversion).
Interface connected fiber optic cable 3,
4 to send.

Reference numerals 12 and 22 denote optical signal receivers (O /
E), the optical signals received from the interface-connected optical fiber cables 3 and 4 are converted into electrical signals (O / E conversion) and output.

Reference numerals 13 and 23 respectively denote a communication control unit (CC).
And controls the communication protocol and the like. here,
In addition to the optical interruption detection function that detects the optical interruption from the received signal state,
It has an idle signal switching mechanism that realizes an optical disconnection notification function that generates an idle signal with a frequency unique to the optical disconnection when it detects an optical disconnection and sends it to the partner transceiver device to immediately notify the partner device of an optical communication error. . This function will be described later with reference to FIG.

Reference numerals 14 and 24 denote processing device connection interface units (AUI; Attachment Unit Interface) to which the processing devices of the communication device main body are electrically connected, and serve as connection interfaces for various LAN devices and the like.

Reference numerals (15) and (16) are indicators (LEDs) which are driven to light when the internal communication control units (CC) 13 and 23 detect light interruption from the received signal state and notify the outside of occurrence of light interruption. is there.

FIG. 2 is a block diagram showing an example of a circuit configuration of an idle signal switching mechanism which is provided in the communication control units (CC) 13 and 23 and which realizes the light disconnection notification function. The circuit is simplified and shown.

In the figure, 31 is an optical signal receiver (O /
E) An optical level detection unit that detects optical interruption from the signal level state of the received signal obtained from 12 (or 22). 32
Is a transmission circuit (T) that generates and outputs transmission data (D) and a transmission signal for optical communication according to an existing idle signal (frequency = 1 MHz), and is in a normal state in which the optical level detection unit 31 does not detect light interruption. Sometimes operation is enabled.

Reference numeral 33 is a partner optical signal transmitter (E / O)
It is a gate circuit that controls the output of an idle signal of a specific frequency (here, 2.5 MHz) to notify 21 (or 11), and becomes operation enable when the light level detection unit 31 detects a light interruption.

Reference numeral 34 is transmission data (D) output from the transmission circuit (T) 32 in a normal state where light interruption is not detected by the optical level detection unit 31, and an existing idle signal (1 MHz).
To the optical signal transmitter (E / O) 11 (or 21),
This is a gate circuit that outputs an idle signal of 2.5 MHz output from the gate circuit 33 to the optical signal transmission unit (E / O) 11 (or 21) when the light level detection unit 31 detects light interruption.

The operation of the embodiment of the present invention will now be described with reference to FIGS. Here, the case where a light interruption occurs in the optical fiber cable 4 is taken as an example. The optical signal transmitted from the optical signal transmission unit (E / O) 11 of the optical transmission / reception device 1 is received by the optical signal reception unit (O / E) 22 of the optical transmission / reception device 2 via the optical fiber cable 3, and the optical-electricity After being converted (O / E conversion), the communication control unit (CC) 23
Then, the presence or absence of light interruption is checked by monitoring the received signal level.

In addition, the optical signal transmitter (E /
The optical signal sent from the O) 21 is transmitted through the optical fiber cable 4 to the optical signal receiving section (O / E) 1 of the optical transceiver 1.
After being received by 2 and subjected to optical-electrical conversion (O / E conversion),
It is input to the communication control unit (CC) 13 and the presence or absence of light interruption is checked by monitoring the received signal level.

At this time, for example, a failure occurs in the optical fiber cable 4, and the communication control unit (CC) 1 of the optical transceiver 1
When 3 detects the light interruption due to the decrease in the received signal level of the optical signal receiving unit (O / E) 12, the communication control unit (CC) 13
Stops the reception, stops the reception from the processing device connection interface unit (AUI) 14 of the optical transceiver 1, and the loopback inside.

Further, the communication control unit (CC) 13 transmits the 2.5 MHz idle signal for notifying the communication partner of the occurrence of the optical interruption, instead of the existing 1 MHz idle signal by the optical interruption detection.

That is, when the optical level detection unit 31 of the communication control unit (CC) 13 detects an optical interruption by monitoring the received signal level, the operation of the transmission circuit (T) 32 is stopped, and instead,
Enables the operation of the gate circuit that outputs the 2.5 MHz idle signal, and replaces the existing 1 MHz idle signal with the 2.5 MHz idle signal that notifies the communication partner of the occurrence of optical interruption. Transmitter (E / O)
Output to 11.

The optical signal transmission unit (E / O) 11 performs electric-optical conversion (E / O conversion) of the 2.5 MHz idle signal received from the communication control unit (CC) 13 and the optical fiber cable 3
To the optical transmission / reception device 2 via.

The optical signal on the optical fiber cable 3 is received by the optical signal receiver (O / E) 22 of the optical transmitter / receiver 2 and is optically-electrically converted (O / E converted), and then the communication controller (CC). ) 23 is input. The communication control unit (CC) 23 recognizes that an optical disconnection has been detected in the partner device, that is, an abnormality has occurred in the optical communication path of the optical fiber cable 4 by detecting the 2.5 MHz idle signal. .

As a result, the communication control section (CC) 23 can clearly recognize the light interruption information of the other party. Further, by displaying the light interruption information on the display device 15 such as an LED, it is possible to visually confirm the occurrence of the light interruption, and it is possible to easily isolate the failure. As a result, both the optical transmission / reception device 1 and the optical transmission / reception device 2 can mutually recognize the respective optical disconnection information, and the abnormality of the optical connection portion at the time of the optical disconnection between the optical transmission / reception devices can be easily separated.

The optical connection monitor of the present invention as described above is widely applicable to optical repeater equipment such as Fiber Optical Inter Repeater Link or other optical communication equipment.

Further, in the above-mentioned embodiment, the communication error is notified to the partner device by transmitting the 2.5 MHz idle signal instead of the 1 MHz idle signal.
The communication device may be configured to notify the partner device of a communication abnormality by transmitting an idle signal of a frequency other than the MHZ and 2.5 MHz idle signals, or the 1 MHZ idle signal is intermittently interrupted in a fixed pattern Accordingly, the communication abnormality may be notified to the partner device.

[0035]

As described above in detail, according to the present invention, in the optical connection monitor between the optical communication devices connected to the optical fiber cable, when the optical disconnection is detected from the received signal state, the optical disconnection is detected. Since it has a function to generate an idle signal specific to the device and send it to the other device, it is possible to immediately notify the other device of the communication error at the time of the light interruption, and the optical connection part at the time of the light interruption between the optical transmitter and receiver devices. It is possible to easily isolate the abnormality of.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of a main part of an optical connection monitor provided in the communication control unit shown in FIG.

[Explanation of symbols]

1, 2 ... Optical transceiver, 3, 4 ... Optical fiber cable, 11, 21 ... Optical signal transmitter (E / O), 12, 22
... Optical signal receiving section (O / E), 13, 23 ... Communication control section (CC), 14, 24 ... Processing device connection interface section (AUI; Attachment Unit Interface), 15, 2
5 ... LED, 31 ... Optical level detecting section, 32 ... Transmission circuit (T), 33 ... Optical disconnection idle signal output control section, 34 ... Transmission signal output section

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Claims (2)

[Claims] 1. An optical connection monitor, wherein each optical communication device is provided with means for generating an idle signal peculiar to the state when a light interruption is detected and transmitting the idle signal to a counterpart device. 2. In an optical communication device connected by an optical fiber cable, a means for generating an idle signal of a first frequency and an idle signal of a second frequency are generated in an optical transceiver of each of the optical communication devices. Means, a means for detecting a light interruption state, and an idle signal of a first frequency is selected when the light interruption state is not detected, and an idle signal of a second frequency is selected when the light interruption state is detected. And an optical connection monitor for notifying the other device of an optical disconnection state by an idle signal.