JPH0787018A - System for monitoring optical subscriber system - Google Patents

Abstract

PURPOSE:To discriminate a fault of an optical fiber cable and a fault of a subscriber unit separately and to discriminate the fault of the each subscriber unit and the fault of each subscriber in-unit circuit. CONSTITUTION:This system os provided with a center station unit 1 having a signal processing circuit 10, an optical transmission circuit 11, a photocoupler 12, an optical reception circuit 13, a low frequency indentification circuit 14 and an alarm circuit 15 which process transmission of an optical signal of an outgoing station side and reception of an incoming optical subscriber signal and an optical monitor signal, indentify the presence and the type of both signals to discriminate the fault of each of optical fibers 2, 4-1 to 4-n and subscriber units 5-1 to 5-n thereby outputting an alarm on the occurrence of a fault and plural subscriber units 5-1 to 5-n. Further, an optical reception circuit 51, a signal processing circuit 52, and optical transmission circuit 53 and a low frequency generating circuit 54 which process the reception of an outgoing station transmission optical signal and send the incoming optical subscriber signal and the optical monitor signal are provided. Furthermore, a photocoupler 3 branching the outgoing station transmission optical signal to the subscriber units 5-1 to 5-n and coupling the incoming optical subscriber signal from the subscriber units 5-1 to 5-n and the optical monitor signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical subscriber system monitoring system, and more particularly to an optical subscriber system monitoring system for monitoring and identifying a fault in each optical fiber cable and subscriber unit in an optical subscriber system.

[0002]

BACKGROUND OF THE INVENTION Since optical cable communication has been used in practical systems, it has undergone many developments. In recent years, in order to flexibly respond to increasingly sophisticated and diversified communication needs, the subscriber network has been changed to optical fiber. Replace with cable FTTH (Fi
The research and development of “ber to the Home” has been actively carried out in various countries around the world. Especially in Japan where subscribers are densely packed and cable laying is mainly fictitious, the metallic subscriber network system introduced in the United States and Australia is used. A certain FTTC (Fiber to the C
urb) is limited in its application area, and FTTH in which an optical transmission device is directly installed in a subscriber is being researched.

An important point in optimizing the subscriber network is that it is more economical than a metallic system by utilizing the wide band property of an optical fiber cable such as a telephone line, high quality audio broadcasting, personal computer communication, CATV and remote meter reading. To provide a wealth of services.

Further, in the typical configuration of the optical subscriber network system, in addition to the SS (Single Star) system in which the center side and the subscriber side are connected to each other in a one-to-one communication, the center side and the subscriber side P is configured by connecting one side to one side N
There is a DS (Passive Double Star) system. In the PDS system, an optical coupler of a passive circuit performs demultiplexing of a down signal from the center side and an up signal from the subscriber side, so that an economical and highly reliable system can be provided. Therefore, FT for narrowband services
In PTH, the PDS method is considered to be promising. In this PDS system, in order to perform bidirectional communication with a large number of subscribers with one core of an optical fiber cable, it is necessary to simultaneously perform bidirectional multiplexing for multiplexing an up signal and a down signal and multiplexing of a subscriber signal.

Here, WDM is used as a method for bidirectional multiplexing.
(Wavelength Division Multi
Iplexing method, TCM (Time Comp)
A compression method and an FDM (Frequency Division Mu)
The TCM method is a method of separately transmitting an upstream signal and a downstream signal in a single-core optical cable so that the upstream signal and the downstream signal do not overlap and collide with each other. Also known as ping-pong transmission. Also called a scheme.
The FDM system sends an upstream signal and a downstream signal at the same optical wavelength, but bidirectional communication is possible by dividing each frequency band into a high band and a low band.

In addition, as a method of multiplexing subscriber signals, WD
M method and TDMA (Time Division M)
There is a multiplexing access) method,
Among them, the TDMA method is a method of embedding an upstream signal of a predetermined time domain transmitted from a subscriber side in a predetermined time domain of a downstream signal transmitted from a center side to perform bidirectional transmission. This is a method of controlling so that the upstream signal and the downstream signal do not collide.

As described above, the system configuration in the PDS system is a combination of the bidirectional multiplexing system and the subscriber signal multiplexing system, and WDM-TD is a typical system configuration.
MA, TCM-TDMA and FDM-TDMA. (Reference: "Trends of optical subscriber networks and future development")
Suzuki, NECTE Technical Report, No. 5, 1992.10) The following techniques are available for monitoring the normality of the optical fiber cable transmission line and the optical transmission / reception means on the subscriber side in the SS system of the above-mentioned optical subscriber system.

First, in an optical subscriber system for transmitting information between a subscriber's home and a center station by an optical fiber cable, a signal for transmitting a signal to the subscriber unit at a fixed time interval to a center station side unit. The subscriber unit includes a transmission / reception circuit that has a generation circuit and a timer, and returns a response signal after detecting this signal, and a response signal detection circuit and an alarm that monitor the transmission of this signal and the response signal returned from the subscriber. And a circuit (Japanese Patent Laid-Open No. 63-193730).
Issue gazette). That is, the feature of this first technology is
The center station periodically sends a monitoring signal to the subscriber side through the optical fiber cable, and the response signal as a result of the subscriber side detecting the monitoring signal returns to the center station side through the optical fiber cable. By monitoring
The point is to determine an abnormality such as a disconnection failure of the optical fiber cable.

Secondly, in the optical transmission system in which the center side and each terminal side perform two-way communication by optical transmission, each terminal side generates a monitoring pulse at predetermined time intervals, and this monitoring pulse is transmitted to other terminals. When the wavelength-multiplexed transmission data and other transmission data are not transmitted, this monitoring pulse is switched to the transmission path of the transmission data and transmitted to the center side, and the transmitted monitoring pulse is detected on the center side. There is a technique (Japanese Patent Laid-Open No. 3-191626) to do so. That is, the feature of the second technique is that the subscriber side generates a monitoring pulse at a predetermined time interval, and the monitoring pulse and the upstream subscriber signal are wavelength-multiplexed and transmitted to the center side or the upstream subscription. The presence or absence of the subscriber signal is monitored, and when the subscriber signal is not transmitted, the subscriber signal is switched to the monitor pulse and the monitor pulse is transmitted to the center side through the subscriber signal transmission circuit. By monitoring the monitoring pulse on the center side, an abnormality such as disconnection of the optical fiber cable transmission line is detected.

Next, description will be made with reference to the drawings. Referring to FIG. 2, which is a block diagram of the optical subscriber system monitoring method as the first technique described above, in this optical subscriber system monitoring method, the center station unit 6 and the subscriber unit 7 are connected by the optical fiber cable 10. Connected SS (Sin
gle Star) format configuration. Here, the center station unit 6 includes a timer 61 that generates time information, a signal generation circuit 62 that receives the time information from the timer 61 and periodically generates a monitoring signal, and normally the center station unit 6 The optical signal transmitted from the station on the downstream side of the subscriber unit 7
Is sent to the subscriber unit 7 and the upstream optical subscriber signal from the subscriber unit 7 is taken into the subscriber unit 7 for optical transmission / reception, and is driven by the monitoring signal a from the signal generating circuit 62 to be converted into an electric-optical signal at regular intervals. To the subscriber unit 7 through the optical fiber cable 10 and output to the subscriber unit 7 through the optical fiber cable 10.
And an optical transmission / reception circuit 63 for inputting an optical response signal to the optical monitoring signal from the center station unit 6 which is sent from the center station unit 6 and performing optical-electrical conversion to branch the response signal e to the detecting means; e and the monitoring signal b from the signal generation circuit 62 are input, the response signal detection circuit 64 which detects the presence or absence of the response signal e and outputs the detection signal f of the result
And an alarm circuit 65 for issuing an alarm indicating that the response signal d from the subscriber unit 7 has not been returned when the detection signal f from the response signal detection circuit 64 is a detection signal without a response signal. Composed of.

Also, the subscriber unit 7 normally sends an upstream optical subscriber signal from the subscriber unit 7 to the center station unit 6 and a downstream station side optical signal from the center station unit 6. The optical monitoring signal from the center station unit 6 is input through the optical fiber cable 10 while performing optical transmission / reception to be taken into the unit 7, and the optical-electrical conversion is performed to output the monitoring signal c and the response signal d to the monitoring signal c. An optical transmission / reception circuit 71 for returning to the center station unit 6 through the optical fiber cable 10, and an optical transmission / reception circuit 7
The presence or absence of the monitoring signal c input from 1 is monitored, and when the monitoring signal c is present, the response signal d indicating that the monitoring signal a is normally transmitted through the optical fiber cable 10 is output to output the optical signal. Response signal sending circuit 72 for sending to the transmitting / receiving circuit 71
Composed of and.

More specifically, the signal generating circuit 62 receives time information from the timer 61 in order to regularly monitor the optical fiber cable 10 and the subscriber unit 7, and receives the monitoring signal a and the monitoring signal a at regular intervals. The signal b is generated and supplied to each optical transmission / reception circuit 63 and the response signal detection circuit 64. The optical transmission / reception circuit 63 normally outputs the station side transmission optical signal transmitted from the center station unit 6 to the subscriber unit 7 to the optical fiber cable 10 as a downstream signal.
At the same time, when the monitoring signal a supplied from the signal generating circuit 62 at regular intervals is input, the signal is electro-optically converted and output to the optical fiber cable 10 as an optical monitoring signal. The optical transmission / reception circuit 71 of the subscriber unit 7 normally carries out optical-electric conversion of the station side optical signal transmitted from the center station unit 6 through the optical fiber cable 10 and takes it into the subscriber unit 7, but at the same time Station unit 6
When an optical monitor signal is input from the device at a constant time, the signal is photoelectrically converted into a monitor signal c, which is supplied to the response signal sending circuit 72. Response signal sending circuit 72
Monitors the presence or absence of the monitoring signal c supplied from the optical transmission / reception circuit 71, and when the monitoring signal c is supplied, the monitoring signal a is normally transmitted from the center station unit 6 side through the optical fiber cable 10. The response signal d indicating that it has been output is output to the optical transmission / reception circuit 71. Optical transmitter / receiver circuit 71
Responds to the center station unit 6 through the optical fiber cable 10 by electro-optically converting the response signal d supplied from the response signal sending circuit 72 into an optical response signal. As a result, the optical transmission / reception circuit 63 of the center station unit 6 performs optical-electrical conversion of the optical response signal returned from the subscriber unit 7 and branches and supplies it to the response signal detection circuit 64 as the response signal e. The response signal detection circuit 64 receives the monitoring signal b from the signal generation circuit 62 and the response signal e from the optical transmission / reception circuit 63 to monitor whether or not both signals are supplied, that is, the signal generation circuit 62 monitors the monitoring signal b. That is, it is monitored whether or not the response signal e is supplied when the monitoring signal a is normally output, and the result is supplied to the alarm circuit 65 as the detection signal f. When the detection signal f from the response signal detection circuit 64 is a detection signal indicating that there is no response signal, the alarm circuit 65
On the assumption that the response signal d has not been returned from the subscriber unit 7, an alarm is issued to notify that there is an abnormality in the optical fiber cable 10 and notifies it.

Next, a first example of the optical transmission monitoring system as the above-mentioned second technique will be described with reference to the block diagram of FIG. In this optical transmission monitoring method, an SS (Single S) in which the station side 8 and the subscriber side 9 are connected by an optical transmission line 11
tar) format. Here, the station side 8 electrically transmits the transmission data g of the station side 8 input via the input terminal A.
An optical transmitter 81 that performs optical conversion and outputs as a downstream station-side transmission optical signal of wavelength λ _{1, and} a downstream station-side transmission optical signal from the optical transmission 81 is output to the optical transmission line 11 to the subscriber side 9. The upstream optical subscriber signal and the optical monitoring signal transmitted from the subscriber side 9 through the optical transmission line 11 at the respective wavelengths λ are transmitted.
A demultiplexer 82 having an orientation that outputs ₂ and wavelength lambda ₃ demultiplexed optical demultiplexer 82 demultiplexes the output wavelength lambda ₂
An optical receiver 83 for opto-electrically converting the upstream optical subscriber signal to output to the output terminal B as reception data h on the station side 8;
An optical receiver 84, which optically-electrically converts the optical monitoring signal of wavelength λ ₃ demultiplexed and output by the optical multiplexer / demultiplexer 82 and outputs the optical monitoring signal as a monitoring pulse m, and a monitoring pulse m from the optical receiver 84. A monitoring pulse detection circuit 85 that detects a direct current level and outputs a trigger pulse after detection for a predetermined time, and resets by a trigger pulse from the monitoring pulse detection circuit 85 to start counting, and whether the next trigger pulse is input or not. When the input interval from the previous trigger pulse is identified and the trigger pulse interval is input every set time, the optical transmission line 1
1 is output to the terminal E, and when the trigger pulse interval is longer than the set time, the counting circuit 86 outputs a signal to the terminal F that the optical transmission line 11 is abnormal. It Further, the subscriber side 9 demultiplexes and inputs into the subscriber side 9 the station side transmitted optical signal of the wavelength λ ₁ transmitted from the station side 8 through the optical transmission line 11, and at the same time, the wavelength λ from the subscriber side 9 a demultiplexer 91 for transmitting a _second uplink optical monitoring signal of an optical subscriber signals and the wavelength lambda ₃ multiplexed in to the station side 8 through the optical transmission line 11, optical multiplexer 91
An optical receiver 92 that optically-electrically converts the downstream station-side transmission optical signal of wavelength λ ₁ demultiplexed and input into the subscriber side 9 to the output terminal C as reception data i on the subscriber side, Subscriber-side upstream subscriber signal j input via input terminal D
Is converted from light to light and supplied to the optical multiplexer / demultiplexer 91 as an optical subscriber signal of wavelength λ ₂ , and a monitoring pulse k for generating and outputting a monitoring pulse k as a monitoring signal at fixed time intervals. A pulse generator 97 and an optical transmitter 98 for electro-optically converting the monitoring pulse k from the monitoring pulse generator 97 and supplying it to the optical multiplexer / demultiplexer 91 as an optical monitoring signal of wavelength λ _3.
A power supply circuit 93 that constantly supplies power to the optical receiver 92 and the optical transmitter 94, and a timer 95 that outputs time information.
And a power supply circuit 96 which is controlled by the time information from the timer 95 and supplies power to the optical transmitter 98 and the pulse generator 97 at regular time intervals.

With this configuration, normal data transmission / reception is performed by call-by-call bidirectional communication. However, in this configuration, a monitoring pulse k sending circuit for monitoring the state of the optical transmission line 11, that is, a monitoring pulse generation. Vessel 97
Is provided on the subscriber side 9. That is, the monitoring pulse k
Is provided on the subscriber side 9, and an optical transmitter 98 for transmitting the monitoring pulse k from the monitoring pulse generator 97 as an optical monitoring signal is provided on the subscriber side 9. There provides light monitoring signal of wavelength lambda ₃ to be outputted to the optical multiplexer 91, demultiplexer optical subscriber signal of wavelength lambda ₂ of the uplink supplied from the optical transmitter 94 in 91 and optical transmitter 98 The wavelength-division-multiplexed signal with the optical monitoring signal having the wavelength λ ₃ from the signal is transmitted to the station side 8. In this case, the power supply for the monitoring pulse generator 97 and the optical transmitter 98 is supplied from the power supply circuit 96, and is separate from the power supply circuit 93 for supplying power to the optical receiver 92 and the optical transmitter 94 for data transmission / reception. There is.
Then, the power supply circuit 9 for generating the monitoring pulse k
6 is set by the timer circuit 95 to operate for a short period of time at regular intervals (for example, it is set to operate for 1 minute every 24 hours). Therefore, the monitoring pulse generator 97 outputs the monitoring pulse k at regular time intervals, and the optical transmitter 98 converts the monitoring pulse k into an electric light signal and converts the monitoring pulse k into an optical monitoring signal of wavelength λ _{3 on} the station side. It is sent to 8 every fixed time. On the station side 8, an optical receiver 84 for receiving the optical monitoring signal of the wavelength λ ₃ is connected to the optical multiplexer / demultiplexer 82, and the received data of the output of the optical receiver 84, that is, the monitoring pulse m is monitored. Supply to the pulse detection circuit 85 for. The monitoring pulse detection circuit 85 performs DC level detection of the monitoring pulse m supplied from the optical receiver 84, outputs a trigger pulse after detection for a certain time or more, and supplies the trigger pulse to the count circuit 86. The count circuit 86 is reset by the trigger pulse supplied from the monitoring pulse detection circuit 85, starts counting from the reset time point, and the next trigger pulse after a time (for example, 24 hours) preset by the timer circuit 95. Is supplied, a signal indicating that the transmission path is normal is supplied to the terminal E when a trigger pulse is supplied every set time.
When the trigger pulse supply interval is longer than the set time, a signal indicating that the transmission path is abnormal is output to the terminal F. Thus, when a signal indicating that the transmission line is abnormal is output to the terminal F, the abnormality of the transmission line is confirmed and notified.

Next, a second example of the optical transmission monitoring method as the above-mentioned second technique will be described with reference to the block diagram of FIG. This optical transmission monitoring system uses the station side 20 and the subscriber side 4
0 is connected by an optical transmission line 30 to an SS (Single)
e Star) format configuration is adopted. Here, the station side 20
Is an optical transmitter 201 that electro-optically converts the transmission data n on the station side 20 input via the input terminal A and outputs it as a downstream station-side transmission optical signal of wavelength λ ₁ , and from the optical transmitter 201. And outputs the optical signal on the downstream station side to the optical transmission line 30 to the subscriber side 40, and transmits the optical signal on the upstream side of the wavelength λ ₂ from the subscriber side 40 through the optical transmission line 30. An optical multiplexer / demultiplexer 202 having directionality for demultiplexing and outputting a monitoring signal, and an upstream optical subscriber signal having a wavelength λ ₂ demultiplexed and input by the optical multiplexer / demultiplexer 202 is optically-electrically converted to a station side 20. And an optical receiver 203 that outputs to the output terminal B as the received data p of the optical monitoring signal of the wavelength λ ₂ demultiplexed and input by the optical multiplexer / demultiplexer 202 and outputs the optical monitoring signal as the monitoring pulse w. , Detect the monitoring pulse w from the optical receiver 203 to DC level Monitoring pulse detection circuit 204 which outputs a trigger pulse after detection for a predetermined time
And the trigger pulse from the monitoring pulse detection circuit 204 resets and starts counting, and the presence / absence of the input of the next trigger pulse and the input interval with the previous trigger pulse are identified, and the trigger pulse interval is set every set time. When input, a signal that the optical transmission line 30 is normal is output to the terminal E, and when the trigger pulse interval is longer than the set time, a signal that the optical transmission line 30 is abnormal is output to the terminal F.
And a counting circuit 205 for outputting Further, the subscriber side 40 sends the station side transmission optical signal of the wavelength λ ₁ transmitted from the station side 20 through the optical transmission line 30 to the subscriber side 40.
Demultiplexing input into the inside and wavelength λ from inside the subscriber side 40
And multiplexing the _two upstream optical subscriber signals and the optical monitoring signal demultiplexer sends to the station side 20 through the optical transmission path 30 4
01 and the downstream side optical signal transmitted from the optical multiplexer / demultiplexer 401 into the subscriber side 40 and having the wavelength λ ₁ are optically-electrically converted to the output terminal C as reception data q on the subscriber side. An optical receiver 402 for outputting and a monitoring pulse generator 40 for generating a monitoring pulse t as a monitoring signal at fixed time intervals.
3, and a switch control circuit 404 for monitoring the presence or absence of an upstream subscriber signal s on the subscriber side input through the input terminal D and outputting a switching control signal according to the presence or absence thereof.
A switch circuit 405 that switches between the upstream subscriber signal s controlled by the switching control signal from the switch control circuit 404 and input through the input terminal D and the monitoring pulse t from the monitoring pulse generator 403, and a switch Circuit 4
And an optical transmitter 406 which converts the upstream subscriber signal or the monitoring pulse t from 05 from electrical to optical and outputs it as an optical subscriber signal of wavelength λ ₂ or an optical monitoring signal and supplies it to the optical multiplexer / demultiplexer 401. , A timer circuit 407 for outputting time information
And a power supply control circuit 408 that controls the optical receiver 402 so as to supply power to the optical transmitter 406 when it receives a station-side transmission optical signal of wavelength λ ₁ from the station side 20,
The power is supplied to the monitoring pulse generator 403 and the optical transmitter 406 for a certain period of time under the control of the time information from the timer circuit 407, and is controlled by the power supply control signal from the power supply control circuit 408 to supply the power to the optical transmitter 406. And a power supply circuit 409 for supplying power.

With this configuration, normal data transmission / reception is performed by call-by-call type bidirectional communication. In this configuration, the switch control circuit 404 monitors whether or not a subscriber signal is supplied from the input terminal D, When there is a subscriber signal, the switch circuit 405 is controlled so that the subscriber signal from the input terminal D is directly supplied to the optical transmitter 406, and when there is no subscriber signal, the monitoring pulse generator 403 monitors. The switch circuit 405 is controlled so that the application pulse t is supplied to the optical transmitter 406. Therefore, according to this configuration, the optical transmitter 406 serves both for the subscriber signal transmission and the monitoring pulse transmission, so that the optical transmitter dedicated to the monitoring pulse becomes unnecessary. In this case, since the switch circuit 405 is switched by determining whether or not the normal path is performed, the normal path is not disturbed by the sending of the monitoring pulse. When the normal pass is performed, it is determined that the optical transmission line 30 is normal without sending the monitoring pulse t.

The optical transmitter 406 and the monitoring pulse generator 403 on the subscriber side 40 are supplied with power from the power supply circuit 409. In this case, the power supply circuit 409 is controlled by the power supply control circuit 408 and the timer circuit 407. The power supply control circuit 408 controls to supply power to the optical transmitter 406 when the optical receiver 402 receives the optical signal transmitted from the station side 20 having the wavelength λ ₁ to the optical transmitter 406, and the timer circuit 407. Performs control such that power is supplied to the optical transmitter 406 and the monitoring pulse generator 403 only for a short time (for example, 1 minute) at regular time intervals (for example, 24 hours). As a result, the monitoring pulse generator 403 outputs the monitoring pulse t at regular time intervals, and the optical transmitter 406 outputs the monitoring pulse t to the input terminal D at the wavelength λ when the upstream subscriber signal is not supplied. _{The second} optical monitoring signal is sent to the station side 20 at regular intervals.

At the station side 20, when an upstream subscriber signal is supplied to the input terminal D of the subscriber side 40, the optical multiplexer / demultiplexer 202 causes the subscriber side 40 to upstreamly add the wavelength λ _2. Signal is input to the optical receiver 203 for demultiplexing,
The optical receiver 203 optically-electrically converts the upstream optical subscriber signal having the wavelength λ ₂ and outputs it to the output terminal B as received data p. When an upstream subscriber signal is supplied to the input terminal D of the subscriber side 40, the optical multiplexer / demultiplexer 202 receives the optical monitoring signal of wavelength λ ₂ from the subscriber side 40 and receives the optical receiver. The signal is demultiplexed to 203, and the optical receiver 203 optically-electrically converts the optical monitoring signal of wavelength λ ₂ and supplies it to the monitoring pulse detection circuit 204 as a monitoring pulse w. The monitoring pulse detection circuit 204 performs DC level detection of the monitoring pulse w supplied from the optical receiver 203, outputs a trigger pulse after performing detection for a certain time or more, and supplies the trigger pulse to the counting circuit 205. The count circuit 205 is reset by the trigger pulse supplied from the monitoring pulse detection circuit 204, starts counting from the reset point, and the next trigger pulse after a time (for example, 24 hours) preset by the timer circuit 407. Is supplied, a signal indicating that the transmission path is normal is output to the terminal E when the trigger pulse is supplied at the set time, and the supply interval of the trigger pulse is longer than the set time. If it is too long, a signal indicating that the transmission path is abnormal is output to the terminal F. Thus, when a signal indicating that the transmission line is abnormal is output to the terminal F, the abnormality of the transmission line is confirmed and notified.

[0019]

In the first conventional optical subscriber system monitoring method, only the presence or absence of a response signal from the subscriber unit 7 is monitored, so that when an alarm is issued, the alarm is issued. Did the alarm occur because the fiber cable 10 failed, or did the subscriber unit 7
It is not possible to determine whether the alarm was issued due to a failure in the.

In the second conventional optical subscriber system monitoring method, it is possible to determine whether there is a fault in the transmission line, but it is not possible to determine a fault in the optical transmitting / receiving means on the subscriber side.

[0021]

According to the optical subscriber system monitoring method of the present invention, a transmission signal transmitted from a station side is electrically transmitted.
Optical conversion is performed and branched and output to the first optical transmission line as a station side optical signal to be transmitted to the corresponding plurality of subscriber side optical transmission / reception means through the first transmission line and the plurality of second optical transmission lines. At the same time, the upstream optical subscriber signal and the optical monitoring signal, which are input from the plurality of subscriber side optical transmitting / receiving means through the plurality of second optical transmission lines and the first optical transmission lines, are branched and input into the inside. A first directional optical transmission / reception means for electrically converting and outputting as an upstream subscriber signal and a monitoring signal, and the presence / absence of the upstream subscriber signal from the first directional optical transmission / reception means Subscriber signal detection means for detecting and outputting subscriber signal detection information for each subscriber side optical transmission / reception means, and monitoring the presence / absence of the monitoring signal input from the first directional optical transmission / reception means and Identify the type of monitoring signal Based on the identified monitoring signal identification information and the subscriber signal detection information from the subscriber signal detection means, a failure of the plurality of subscriber side optical transmission / reception means, the first optical transmission line and the plurality of 2, a station side optical transmitting / receiving means having a station side discriminating means for discriminating a failure of the optical transmission line and outputting a corresponding first alarm signal, and the downlink station side sending from the station side optical transmitting / receiving means. The optical signal is branched and input to the inside to be optically-electrically converted and output as a transmission signal on the station side, and the internal reception processing function is monitored to output a second alarm signal when there is an abnormality and the second alarm signal. Is not output during normal operation, the upstream subscriber signal from the subscriber side terminal is electro-optically converted and output as the optical subscriber signal, and when the second alarm signal is output The optical subscriber message that had been output until then Of the monitoring signal is converted into a signal for optical-optical conversion and output as an optical monitoring signal, which is branched and output to the second transmission line to output the second optical transmission line and the first optical transmission. A second directional transmission / reception means for transmitting to the station side optical transmission / reception means through a path, and a plurality of subscriber side optical transmission / reception means to which the second alarm signal from the second directional transmission / reception means is input. The plurality of subscriber-side optical transmitting / receiving means, each of which has a plurality of types of monitoring signals to identify and supplies to the second directional transmitting / receiving means, the monitoring signal generating means, and the first optical transmission line. Via the plurality of second optical transmission lines, the downstream station-side optical transmission signals from the station-side optical transmission / reception means are transmitted to the plurality of subscriber-side optical transmission / reception means, and the plurality of subscriber-side optical transmission / reception means are transmitted. The duplicate transmitted through the second optical transmission line. A plurality of optical transmission / reception means on the subscriber side and an optical branching / coupling means for coupling the upstream optical subscriber signal and the optical monitoring signal to the optical transmission / reception means on the station side through the first optical transmission line. .

In the optical subscriber system monitoring method according to the present invention, the downlink transmission signal which is continuous in time from the upper side of the station is input and converted into a burst-like signal which is intermittent in time and is transmitted from the station side. Is output as an upstream subscriber signal of a bursty signal that is intermittently output in time, and is converted to a signal that is continuous in time, and is sent to the station side upper side, and the plurality of subscriber side optical transmission / reception means for each of the upstream side First signal processing means for detecting the presence / absence of a subscriber signal and outputting it as subscriber signal detection information, and station-side transmission light by electro-optically converting the station-side transmission signal from the first signal processing means. First optical transmission means for outputting as a signal, and branching to the first optical transmission line for transmitting the station side optical transmission signal from the first optical transmission means to the plurality of subscriber side optical transmission / reception means Output and output the first optical transmission First optical branching means having directivity for internally branching and inputting an upstream optical subscriber signal and an optical monitoring signal from the plurality of subscriber side optical transmitting / receiving means which are input through a path. The optical subscriber signal and the optical supervisory signal branched and input from the branching means are optically-electrically converted to output the upstream subscriber signal and the supervisory signal, and the subscriber signal is subjected to the first signal processing. And a monitor for monitoring the presence or absence of the monitor signal from the first light receiver and for identifying the type of the monitor signal and outputting the monitor signal identification information. Signal identifying means, the supervisory signal identifying information from the supervisory signal identifying means, and the subscriber signal detection information from the first signal processing means, and the first optical transmission line and the plurality of optical signals. Subscriber side light A station side light having an alarm discriminating means for discriminating a fault in a plurality of second transmission lines connected to a receiving means and a fault for each of the plurality of subscriber side optical transmitting / receiving means and outputting a corresponding first alarm signal. Transmitting and receiving means, and the downlink station side optical transmission signal from the station side optical transmitting and receiving means is branched and input into the inside, and the uplink optical subscriber signal and optical monitoring signal from the inside are transmitted to the station side optical transmitting and receiving means. Second optical branching means having directivity for branching and outputting to the second optical transmission line for sending to the second optical transmission line, and the downlink station-side outgoing optical signal branched and input into the inside from the second optical branching means Second optical receiving means for optically-electrically converting and outputting as a station-side transmission signal, monitoring the functional operation of itself and outputting a second alarm signal when there is an abnormality, and the second optical receiving means. The station-side transmission signal from the means is temporally The intermittent burst signal is converted into a temporally continuous signal and transmitted to the subscriber side terminal, and the temporally continuous upstream subscriber signal from the subscriber side terminal is converted into a temporally intermittent burst signal. Second signal processing means for converting and taking in the inside, monitoring the functional operation of itself and outputting a third alarm signal when there is an abnormality, and the second alarm from the second light receiving means. Monitoring signal generating means for generating and outputting a plurality of types of monitoring signals corresponding to respective signals when at least one of the signal and the third alarm signal from the second signal processing means is input, From the second signal processing means during normal operation when neither the second warning signal from the second light transmitting / receiving means nor the third warning signal from the second signal processing means is output. Taken in The upstream subscriber signal is electro-optically converted and output as the upstream optical subscriber signal to output the second alarm signal from the second optical receiving means and the second alarm signal from the second signal processing means. When any one of the alarm signals of No. 3 is input in an abnormal state, the output of the upstream optical subscriber signal, which has been output until then, is stopped and the monitoring signal from the monitoring signal generating means is replaced with the optical-electrical signal. The plurality of subscriber side optical transmitting / receiving means having a second optical transmitting means for converting and outputting as the optical monitoring signal and supplying to the second optical branching means, and transmission through the first optical transmission path. The downstream station side optical transmission signals from the station side optical transmitter / receiver are distributed to the plurality of second optical transmission lines and transmitted to the plurality of subscriber side optical transmitters / receivers and the plurality of second side optical transmitters / receivers are transmitted. The plurality of subscriber side lights transmitted through the transmission line of Coupling the optical subscriber signals and the optical monitoring signal of the uplink from the receiving means to and an optical branching and coupling means for transmitting to said station side light receiving means through said first optical transmission path.

Further, in the optical subscriber system monitoring method according to the present invention, the monitoring signal generating means generates a plurality of types of analog low frequency signals.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. Referring to FIG. 1 showing an embodiment of the present invention, in this optical subscriber system monitoring method, a center station unit 1 and a plurality of subscriber units 5 _{-1 to} 5 _-n are connected to an optical fiber via an optical coupler 3. Cable 2 and optical fiber cable 4 _-1 to 4
_-n connected PDS (Passive Double)
le Star) format configuration.

Here, the center station unit 1 receives bursts of temporally continuous signals from a multiplexer, a switch, a high-speed digital line, a video line, a public line or the like on the upper side of the station and bursts intermittently in time. The signal processing such as conversion to a dynamic signal is performed and output to the center station unit 1 as a station-side transmission signal, and the optical signal is transmitted in the center station unit 1.
Performs signal processing such as converting the upstream subscriber signal of the electrically converted bursty signal into a continuous signal, and sends it to the multiplexer, switch, high speed digital line, video line, public line, etc. on the upper side of the station. A signal processing circuit 1 for detecting the presence / absence of an upstream subscriber signal for each of a plurality of subscriber units sent from the subscriber side and outputting subscriber signal detection information μ.
0 and the optical signal sent from the signal processing circuit 10 on the station side are electrically
An optical transmission circuit 11 that performs optical conversion and outputs as a downstream station-side transmission optical signal, and a downstream station-side transmission optical signal from the optical transmission circuit 11 is branched and output to the optical fiber cable 2 for transmission to the subscriber side. An optical coupler 12 having a directivity for branching and inputting an upstream optical subscriber signal or an optical monitoring signal from the subscriber side input through the optical fiber cable 2 into the center station unit 1, and from the optical coupler 12 to the center station. The upstream optical subscriber signal or the optical supervisory signal branched and input into the unit 1 is optically-electrically converted to supply the upstream subscriber signal to the signal processing circuit 10 and the supervisory signal δ to the low frequency discrimination circuit 14. Optical receiver circuit 13 for supplying and optical receiver circuit 1
A low-frequency identification circuit 14 which receives the monitoring signal δ from the signal No. 3 and monitors whether or not the monitoring signal δ is supplied, and which identifies the frequency component of the monitoring signal δ and outputs the monitoring signal identification information θ. The monitoring signal identification information .theta. From the low frequency identification circuit 14 and the subscriber signal detection information .mu. From the signal processing circuit 10 are input, and the failure and the optical fiber cable 2 for each of the subscriber units 5 _{-1 to} 5 _-n or Optical fiber cable 4
An alarm circuit 15 which discriminates between _-1 to 4 _-n faults and outputs a corresponding alarm signal π to notify.

Further, the subscriber unit _5-1, the optical fiber cable 2 from the center station unit 1, the optical coupler 3 and the optical fiber cable 4 subscriber station side sending optical signals of the downlink input through _-1 Unit 5 _- optical fiber cable _4-1 and outputs the upstream optical subscriber line signal and an optical monitoring signal from the subscriber unit within 1 with branching input within ₁ to the optical fiber cable _4-1, the optical coupler 3 and the optical fiber An optical coupler 50 having a directivity for transmitting to the center station unit 1 through the cable 2 and a downstream station side optical signal branched and input from the optical coupler 50 into the subscriber unit 5 _-1 are optically-electrically converted into a station. The optical receiving circuit 51 which outputs a warning signal α when it outputs an output signal as a side transmission signal and monitors the functional operation in its own circuit and there is an abnormality, and the optical receiving circuit 51 intermittently operates in time. Signal processing such as conversion of a downstream station transmission signal of a burst signal into a temporally continuous signal is performed and transmission is performed to a subscriber terminal such as a multiplexing device, a data terminal, an image terminal and an ISDN telephone terminal on the terminal side. For converting a time-continuous signal of an upstream subscriber signal input from a subscriber terminal such as a terminal side multiplexer, a data terminal, an image terminal and an ISDN telephone terminal into a burst-like signal which is intermittent in time. a signal processing circuit 52 for outputting an alarm signal β when with recording on a the subscriber unit _25-1 performs signal processing monitors the functional operation of the self circuit is abnormal, an alarm signal from the light receiving circuit 51 α and signal processing circuit 52
No alarm signal β from the subscriber unit 5 _-1 is input, the subscriber unit 5 _-1 is normally _operated under normal conditions, and the upstream subscriber signal taken into the subscriber unit 5 _-1 from the signal processing circuit 52 is electrically supplied. Optically converted and supplied as an optical subscriber signal to the optical coupler 50, but when either or both of the alarm signal α from the optical receiving circuit 51 and the alarm signal β from the signal processing circuit 52 are input, they are output by that time. The output of the upstream optical subscriber signal which has been performed is stopped and the low frequency generation circuit 54 is used instead.
The monitoring signal .gamma. From the optical transmission circuit 53 is electro-optically converted and supplied to the optical coupler 50 as an optical monitoring signal. In addition, the subscriber unit 5 _-2 to the subscriber unit 5
_-n also has the same function as the subscriber unit _5-1 and has the same circuit configuration.

The center station unit 1 configured as above
And the subscriber units 5 _{-1 to} 5 _-n are the center station unit 1
Is connected to the optical fiber cable 2, and each of the subscriber units 5 _{-1 to} 5 _-n corresponds to the optical fiber cable 4 _-1.
To 4- _n , each of which is connected to each of the optical couplers 3, and the optical signal from the center station unit 1 is transmitted from the center station unit 1 and the subscriber unit 5 _{-1 to} 5 _{-n is connected} to each of the upstream optical signals. The master signal and the optical monitoring signal are branched, that is, demultiplexed, and bidirectionally communicated.

More specifically, the signal processing circuit 10 of the center station unit 1 is inputted with temporally continuous signals transmitted from a multiplexer, a switch, a high speed digital line, a video line or a public line on the station side. Then, this is subjected to signal processing such as conversion into a burst signal which is intermittent in time, and is supplied to the optical transmission circuit 11 as a station side transmission signal. The optical transmission circuit 11 converts the station-side transmission signal from the signal processing circuit 10 into an optical signal and converts the signal into a downstream station-side transmission optical signal.
Supply to. The directional optical coupler 12 branches the outgoing station side optical signal from the optical transmission circuit 11 to the optical fiber cable 2. The downstream station side optical signal transmitted from the center station unit 1 transmitted through the optical fiber cable 2 is input to the optical coupler 3 composed of a passive circuit and is branched into n, and the optical fiber cables 4 _-1 to 4 _-n are connected. Each of them is transmitted and supplied to each of the plurality of subscriber units 5 _{-1 to} 5 _-n .
The optical coupler 50 having the respective directivities of the subscriber units 5 _{-1 to} 5 _-n branches the optical signals transmitted from the optical fiber cables 4 _-1 to 4 _-n and inputs the optical signals on the station side to input the optical signals. Receiver circuit 5
Supply to 1. The optical receiving circuit 51 performs optical-electrical conversion of the downstream station side optical transmission optical signal branched and input by the optical coupler 50 and supplies it to the signal processing circuit 52 as a station side transmission signal, and at the same time, performs the functional operation inside its own circuit. If an abnormality is detected by monitoring, an alarm signal α is output and supplied to the optical transmission circuit 53 and the low frequency generation circuit 54. The signal processing circuit 52 is the optical receiving circuit 5
1. A subscriber side multiplexer, data terminal, image terminal and ISDN telephone terminal by performing signal processing such as converting a station side transmission signal of a temporally intermittent burst signal from 1 into a time continuous signal. Etc. Further, the signal processing circuit 52 converts a temporally continuous signal from the multiplexer, data terminal, image terminal, ISDN telephone terminal, etc. on the subscriber side into a burst-like signal which is temporally intermittent and converts the subscriber unit 5. _-1 is supplied and supplied to the optical transmission circuit 53, and at the same time, the functional operation inside its own circuit is monitored, and if there is an abnormality, an alarm signal β is output and supplied to the optical transmission circuit 53 and the low frequency generation circuit 54. When the low-frequency generation circuit 54 receives an alarm signal α from the optical receiver circuit 51 and / or an alarm signal β from the signal processing circuit 52 at the same time,
In the case of the subscriber unit 5 _-1 , when the alarm signal α is input, a low frequency signal of the frequency f ₁₁ is generated to generate the monitoring signal γ.
When the alarm signal β is input, the frequency f
_Twelve low frequency signals are generated and output as a monitoring signal γ. When the alarm signal α and the alarm signal β are input at the same time, a low frequency signal of frequency f ₁₃ is generated and output as the monitoring signal γ. Frequency of the low-frequency signal as a monitor signal γ to the low frequency generation circuit 54 is generated differs in each subscriber unit _5-1 to 5 _-n, each in the above-described conditions if the subscriber unit 5 _-1 Each of the frequencies f ₁₁ , f ₁₂ and f ₁₃ is a subscriber unit _5-2.
In the case of, the respective frequencies f ₂₁ , f ₂₂ and f ₂₃ are the same under the same conditions as the subscriber unit 5 _-1 . Also,
In the case of the subscriber unit 5- _n , the frequencies are f _n1 , f _n2 and f _n3 . The low frequency signals of the monitoring signal γ generated by the low frequency generation circuit 54 are all analog signals that are temporally continuous. Optical transmission circuit 53
Is an optical coupler which, when both the optical receiving circuit 51 and the signal processing circuit 52 are operating normally, performs an electrical-optical conversion of the upstream subscriber signal from the signal processing circuit 52 and outputs it as an optical subscriber signal. The alarm signal α from the optical receiving circuit 51 or the alarm signal β from the signal processing circuit 52
When an error is input, the output of the optical subscriber line signal that has been output until then is stopped, and instead, the monitoring signal γ from the low frequency generation circuit 54 is electro-optically converted into an optical monitoring signal. It is output and supplied to the optical capella 50. The optical coupler 50 of each of the directional subscriber units 5 _{-1 to} 5 _-n is normally
The upstream optical subscriber line signal from the optical transmission circuit 53 is branched and output to each of the corresponding optical fiber cables 4 _-1 to 4 _-n , but when there is an abnormality, the optical subscriber signal that has been transmitted until then is output. Instead, the optical fiber cable that supports optical monitoring signals _4-1 to
Branch output to each 4- _n .

The optical coupler 3 is directly connected to each of the subscriber units 5 _{-1 to} 5 _-n through the optical fibers 4 _-1 to 4 _{-n to} receive the optical signals from the subscriber units 5 _{-1 to} 5 _-n . In a normal state in which the alarm signal α or the alarm signal β is not output from either the circuit 51 or the signal processing circuit 52, the upstream optical subscriber line signal from each of the subscriber units 5 _{-1 to} 5- _n Center station unit 1 through optical fiber cable 2
When any of the subscriber units 5 _{-1 to} 5 _-n has an abnormality, the alarm signal α or the alarm signal is output from either the optical receiving circuit 51 or the signal processing circuit 52 of the corresponding abnormal subscriber unit. At the time of the abnormality that β is output, the optical monitoring signal sent from the corresponding abnormal subscriber unit is combined with the optical subscriber line signal sent from each of the other normal subscriber units to connect to the center station. Send to unit 1. The upstream optical subscriber line signal and the optical monitoring signal combined by the optical coupler 3 are input to the optical coupler 12 of the center unit 1 through the optical fiber cable 2 and branched and supplied to the optical receiving circuit 13. The optical receiving circuit 13 performs optical-electrical conversion on the upstream optical subscriber line signal and the optical monitoring signal from the optical coupler 12 to obtain an upstream subscriber signal and monitoring signal .delta. Supply to. The signal processing circuit 10 performs signal processing such as converting an upstream subscriber line signal from the optical receiving circuit 13 from a bursty signal that is intermittent in time into a signal that is continuous in time. , Sends to an exchange or a digital public line, detects the presence or absence of an upstream subscriber signal for each of the subscriber units 5 _{-1 to} 5 _-n , and outputs subscriber signal detection information μ,
Supply to the alarm circuit 15. Further, the low frequency identification circuit 14 monitors the presence or absence of the monitoring signal δ supplied from the optical receiving circuit 13, and when the monitoring signal δ is supplied, it identifies the frequency type of the monitoring signal δ, and the subscriber Unit 5
Every _{-1 to} 5 _-n and the optical receiving circuit 51 and the signal processing circuit 52
The identification result for each is supplied to the alarm circuit 15 as the monitoring signal identification information θ. The alarm circuit 15 receives the monitoring signal identification information θ from the low frequency identification circuit 14 and the subscriber signal detection information μ for each of the subscriber units 5 _{-1 to} 5 _-n from the signal processing circuit 10 to perform signal processing. When the detection information indicating that there is no subscriber signal is input from the circuit 10, it is determined that there is an abnormality in the subscriber unit if the monitoring signal identification information θ from the low frequency identification circuit 14 is not input, and Based on the monitoring signal identification information θ, it is determined which subscriber unit, which optical receiving circuit 51, and signal processing circuit 52 have become abnormal, and a corresponding alarm signal π is output to notify.
When the subscriber signal detection information μ from the signal processing circuit 10 is the detection information indicating that there is no subscriber signal, the low frequency identification circuit 1
If the monitoring signal identification information θ from 4 is not input, the optical fiber cable 2 or the optical fiber cable 4 _-1
An alarm signal π indicating that 4- _n is abnormal is output and notified.

Here, multiplexing of the optical subscriber signal or the optical monitoring signal from each of the subscriber units 5 _{-1 to} 5 _-n connected by the optical coupler 3 is performed by WDM multiplexing or TDMA multiplexing. Further, an optical subscriber signal to the center station unit 1 coupled by the optical coupler 3 and a downstream station side optical transmission signal from the center station unit 1 to the subscriber units 5 _{-1 to} 5 _-n via the optical coupler 3. Bi-directional multiplexing with and is performed by WDM multiplexing, TCM multiplexing, or FDM multiplexing. These multiplexing methods are used to prevent uplink and downlink signals from overlapping and colliding.
Alternatively, the downlink signal from the center station unit 1 side can be identified and received by each subscriber side terminal subordinately connected to the subscriber units 5 _{-1 to} 5 _-n , and each subscriber side In order that the subscriber signal from the terminal can be easily identified and received by the center station unit 1 or other facility on the center side connected to the center station unit 1, the host unit of the center unit 1 and the subscriber units 5 _{-1 to} 5 _-n can be easily received. Since it is a method that is predetermined by a multiplexer or the like connected to the lower order of the above and is not a technology to be referred to again in this optical subscriber system monitoring method, its detailed description is omitted. However, it is apparent from the above description that this optical subscriber system monitoring method can be applied to any multiplexing method.

[0031]

As described above, according to the present invention, it is possible to distinguish between a failure of an optical fiber cable and a failure of a subscriber unit, and a failure for each subscriber unit and optical reception of each unit. It is possible to distinguish between the means and the signal processing means by distinguishing between them. Further, since the analog low frequency signal is used as the monitoring signal, the monitoring signal generating means and the monitoring signal identifying means can be realized with a simple configuration.

[Brief description of drawings]

FIG. 1 is a block diagram showing an optical subscriber system monitoring method according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a first conventional example.

FIG. 3 is a block diagram showing a first example of a second conventional example.

FIG. 4 is a block diagram showing a second example of the second conventional example.

[Explanation of symbols]

1 center station unit 2 optical fiber cable 3 optical coupler 4 _-1 to 4- _n optical fiber cable 5 _{-1 to} 5 _-n subscriber unit 10 signal processing circuit 11 optical transmitting circuit 12 optical coupler 13 optical receiving circuit 14 signal separating circuit 15 Low frequency identification circuit 16 Alarm circuit 51 Optical receiving circuit 52 Signal processing circuit 53 Optical transmission circuit 54 Low frequency generation circuit α Warning signal β Warning signal γ Monitoring signal δ Monitoring signal θ Monitoring signal identification information μ Subscriber signal detection information π Alarm signal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Suzuki 1-4-2, Mita 1-chome, Minato-ku, Tokyo NEC Transmission Engineering Co., Ltd.

Claims (3)

[Claims] 1. A transmission signal transmitted from a station side is subjected to electrical-optical conversion and branched and outputted as a station side transmission optical signal to a first optical transmission line to output the first transmission line and a plurality of second optical transmission lines. Upstream light that is transmitted to the corresponding plurality of subscriber side optical transmitting / receiving means through the optical path and is input from the plurality of subscriber side optical transmitting / receiving means through the plurality of second optical transmission paths and the first optical transmission paths. First directional optical transmitting / receiving means for branching and inputting the subscriber signal and the optical monitoring signal into the inside, and performing optical-electrical conversion to output as an upstream subscriber signal and the monitoring signal;
A subscriber signal detecting means for detecting presence or absence of the upstream subscriber signal from the first directional optical transmitting / receiving means for each of the plurality of subscriber side optical transmitting / receiving means and outputting subscriber signal detection information; The presence / absence of the monitoring signal input from the first directional light transmitting / receiving unit is monitored, the type of the monitoring signal is identified, and the identified monitoring signal identification information and the subscriber signal detection unit are identified. Based on the subscriber signal detection information, the failure of the plurality of subscriber side optical transceivers and the first
Optical transmission line and a plurality of second optical transmission lines, and a station side optical transmission / reception unit having a station side determination unit for outputting a corresponding first alarm signal, and the station side optical transmission / reception unit The downstream station-side transmission optical signal from the means is input to the inside for optical-electric conversion to output as a station-side transmission signal, and the internal reception processing function is monitored, and when there is an abnormality, a second alarm signal is issued. In the normal state in which the second alarm signal is not output, the upstream subscriber signal from the subscriber side terminal is electro-optically converted and output as the optical subscriber signal, and the second alarm is output. When the signal is output abnormally, the output of the optical subscriber signal that has been output until then is stopped, and instead the monitoring signal is electro-optically converted and output as an optical monitoring signal, and the second transmission is performed. Output to the second optical transmission line and the first optical transmission line. Second directional transmission / reception means for transmitting to the station side optical transmission / reception means through the optical transmission line of the above, and the plurality of subscriber side optical signals input with the second alarm signal from the second directional transmission / reception means. A plurality of subscriber-side optical transmitting / receiving means, each of which has a plurality of types of monitoring signals for identifying the transmitting / receiving means and which supplies the monitoring signal generating means for supplying the monitoring signals to the second directional transmitting / receiving means; The downlink station-side transmission optical signal from the station-side optical transmission / reception means transmitted through the optical transmission path is branched to the plurality of second optical transmission paths and transmitted to the plurality of subscriber-side optical transmission / reception means. The station is connected through the first optical transmission path by combining the upstream optical subscriber signal and the optical monitoring signal from the plurality of subscriber side optical transmission / reception means transmitted through the plurality of second optical transmission paths. Transmit to side light transmitting / receiving means An optical subscriber system monitoring method comprising: an optical branching / coupling means. 2. A burst-like signal, which is input from a station-side higher-order downlink transmission signal, is converted into a temporally intermittent burst signal, and is output as a station-side outgoing optical signal, and is temporally intermittent. A subscriber is converted by converting an upstream subscriber signal into a temporally continuous signal and transmitting the signal to the upper station side, and detecting the presence or absence of the upstream subscriber signal for each of a plurality of subscriber side optical transmitting / receiving means. First signal processing means for outputting as signal detection information, and first optical transmitting means for electro-optically converting the station-side transmission signal from the first signal processing means and outputting as a station-side transmission optical signal. , Through the first optical transmission line while branching and outputting the station-side transmission optical signal from the first optical transmission unit to the plurality of subscriber-side optical transmission / reception units Optical transmission / reception of the plurality of subscribers input First optical branching means having directivity for internally branching and inputting an upstream optical subscriber signal and an optical monitoring signal from the receiving means, and the optical adder branched and input internally from the first optical branching means First optical receiving means for optically-electrically converting the subscriber signal and the optical supervisory signal to output the upstream subscriber signal and the supervisory signal and supplying the subscriber signal to the first signal processing means, Monitoring signal identifying means for monitoring the presence or absence of the monitoring signal from the first light receiving means, identifying the type of the monitoring signal and outputting monitoring signal identification information, and the monitoring signal identifying means. From the monitoring signal identification information from the first signal processing means and the subscriber signal detection information from the first signal processing means, and are connected to the first optical transmission line and the plurality of subscriber side optical transmitting / receiving means. There is no obstacle in the second transmission line. And a station side optical transmission / reception means having an alarm discrimination means for discriminating a fault for each of the plurality of subscriber side optical transmission / reception means and outputting a corresponding first alarm signal, and the downlink from the station side optical transmission / reception means. Of the optical signal transmitted from the station side to the inside, and branched to the second optical transmission line for transmitting the upstream optical subscriber signal and the optical monitoring signal from the inside to the station side optical transmitting / receiving means. A second optical branching unit having a direction to output, and the downlink station-side outgoing optical signal that is internally branched and input from the second optical branching unit is optically-electrically converted and output as a station-side outgoing signal. If there is an abnormality by monitoring its own functional operation with
Second optical receiving means for outputting the alarm signal of the above, and the station side transmission signal from the second optical receiving means is converted from a burst signal intermittent in time into a signal continuous in time, and the subscriber The upstream subscriber signal sent to the terminal on the side of the subscriber and continuous in time from the subscriber terminal is converted into a burst signal which is intermittent in time to be taken in, and its own functional operation is monitored for abnormality. A second signal processing means for outputting a third alarm signal, the second alarm signal from the second light receiving means, and the third alarm signal from the second signal processing means. Monitoring signal generating means for generating and outputting a plurality of types of monitoring signals corresponding to each when at least one is input, the second alarm signal from the second optical transmission / reception means, and the second alarm signal. The second from the second signal processing means In the normal state in which none of the alarm signals of (1) is output, the upstream subscriber signal that is taken in from the second signal processing means is electro-optically converted and output as the upstream optical subscriber signal. When one of the second alarm signal from the second light receiving means and the third alarm signal from the second signal processing means is input, the upstream output that has been output up to that time is abnormal. Secondly, the output of the optical subscriber signal is stopped and, instead, the monitoring signal from the monitoring signal generating means is optoelectrically converted and output as the optical monitoring signal and is supplied to the second optical branching means. And a plurality of subscriber side optical transmission / reception means, and the station side optical transmission / reception means transmitted from the station side optical transmission / reception means via the first optical transmission line. The plurality of subscribers by distributing to the two optical transmission lines The upstream optical subscriber signal and the optical monitoring signal from the plurality of subscriber side optical transceivers transmitted to the optical transmitter / receiver and transmitted through the plurality of second transmission lines are combined to combine the first optical subscriber signal and the optical supervisory signal. An optical subscriber system monitoring method, comprising: an optical branching / coupling means for transmitting the optical transmission / reception means to the station side through an optical transmission line. 3. The monitoring signal generating means generates a plurality of types of analog low frequency signals.
Or the optical subscriber system monitoring method described in 2.