JP5475298B2 - Optical terminal device and optical transmission system including the same - Google Patents

Description

  The present invention relates to an optical terminal device that is installed on the subscriber side of an optical transmission system and converts a received broadcast optical signal into an electrical signal, and an optical transmission system including the optical terminal device. The optical terminal device has an optical subscriber terminal device for broadcasting (V-ONU: Video-Optical Network Unit) and an optical subscriber terminal device for communication (D-ONU: Digital-Optical Network Unit). It may be a person terminal device (V / D-ONU) or a V-ONU.

  In an optical transmission system such as a cable television broadcasting system using an optical fiber cable, an optical terminal device (see, for example, Patent Documents 1 to 3) is installed for each subscriber house.

JP 2007-288384 A (paragraph 0022, FIG. 2) JP 2007-124175 A (paragraph 0034, paragraph 0035, FIG. 4) Utility Model Registration No. 3134762 (Summary)

  However, the conventional optical terminal device does not have a function of determining whether or not the RF output signal is normal, and the serviceman or the subscriber cannot immediately grasp the state of the RF output signal, so that the optical terminal There has been a problem that operation confirmation at the time of installation of the device and identification of the cause when a broadcast reception failure occurs become complicated.

  Therefore, it is conceivable to add a function for determining whether or not the RF output signal is normal to the optical terminal device. However, there is a possibility that an erroneous determination may occur in determining whether the RF output signal is normal due to analog stoppage of terrestrial television broadcasting after July 24, 2011. Also, if the wave number (number of channels) of the broadcast wave transmitted by the optical transmission system is changed in the future due to factors other than the analog wave stop of terrestrial television broadcasting, is the RF output signal normal as well? There is a risk of erroneous determination in determining whether or not.

  In view of the above situation, the present invention provides an optical terminal device that can determine whether an RF output signal is normal and can prevent erroneous determination in the determination, and an optical transmission system including the optical terminal device. The purpose is to provide.

  To achieve the above object, an optical terminal device according to the present invention is an optical terminal device that inputs an optical signal and outputs an RF output signal based on the optical signal, and the level of the RF output signal is normal Determination means for determining whether or not, storage means for storing a determination reference value used for determination by the determination means, determination result output means for outputting a determination result of the determination means, and change of the determination reference value An extraction means for extracting a determination reference value change command for instructing from the optical signal, and a change means for changing the determination reference value stored in the storage means based on the determination reference value change command; To do.

  According to such a configuration, since the determination means for determining whether or not the level of the RF output signal is normal is provided, it can be determined whether or not the RF output signal is normal. Furthermore, according to such a configuration, since the determination unit stores the determination reference value stored in the storage unit based on the determination reference value change command, for example, a broadcast wave transmitted by the optical transmission system is provided. Even when the wave number (number of channels) is changed in the future, it is possible to prevent erroneous determination in determining whether the RF output signal is normal.

  The storage means is preferably a non-volatile memory. Thereby, even when the power supply to the optical terminal device is interrupted due to a power failure or the like and then recovered, the determination reference value can be stored.

  In order to achieve the above object, an optical transmission system according to the present invention includes the optical terminal device having any one of the above configurations, a remote control device that remotely controls the optical terminal device, and an optical transmission device, The remote control device outputs a determination reference value change command for instructing change of the determination reference value, and the optical transmission device converts an electrical signal including the determination reference value change command into an optical signal, and converts the optical signal into the optical signal. The transmission is made to the optical terminal device.

  According to the present invention, the optical terminal device determines whether the level of the RF output signal is normal, and changes the determination reference value stored in the storage means based on the determination reference value change command. Since the change means is provided, it can be determined whether or not the RF output signal is normal, and erroneous determination in the determination can be prevented.

These are figures which show schematic structure of the optical transmission system for CATV which concerns on 1st Embodiment of this invention. These are perspective views which show the example of an external appearance of the optical terminal device used with the optical transmission system for CATV shown in FIG. These are figures which show the example of schematic structure of the optical terminal device used with the optical transmission system for CATV shown in FIG. These are figures which show the example of a data structure of the determination reference value change command. These are figures which show the other example of a data structure of the determination reference value change command. These are figures which show schematic structure of the optical transmission system for CATV which concerns on 2nd Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an optical transmission system for CATV according to the first embodiment of the present invention. The optical transmission system shown in FIG. 1 includes a V-ONU remote control personal computer (hereinafter referred to as a V-ONU remote control personal computer) 1, an FSK (Frequency Shift Keying) modulator 2, a mixer 3, and optical transmission. Device 4, optical fiber 5, optical branching device 6, optical fibers 7-1 to 7-n, V-ONUs 8-1 to 8-n having a remote control function, and television receivers 9-1 to 9 -N , subscriber-side personal computers (hereinafter referred to as subscriber-side personal computers) 10-1 to 10 -n , D-ONUs 11-1 to 11-n, optical fibers 12-1 to 12-n, and optical branching Device 13, optical fiber 14, and communication system device 15.

  The V / D-ONU 16-1 that is an example of the optical terminal device according to the present invention includes a V-ONU 8-1 and a D-ONU 11-1. The same applies to V / D-ONUs 16-2 to 16-n, which are examples of the optical terminal device according to the present invention, and V / D-ONU 16-k includes V-ONU 8-k and D-ONU 11-k. (K is a natural number of 2 or more and n or less). The V-ONU remote control personal computer 1 is an example of a remote control device described in claims. The optical transmitter 4 is an example of an optical transmitter according to the claims. In addition, the V-ONU remote control specification in the optical transmission system shown in FIG. 1 is based on the V-ONU remote control operation specification (JCL SPEC-014 1.0 version) established by Nippon Cable Lab.

A V-ONU remote control PC 1, the FSK modulator 2, the mixers 3, an optical transmitter 4, a communication system device 1 5 is installed in the center station, an optical branching unit 6 and 13 in the transmission line V / D-ONUs 16-1 to 16-n, television receivers 9-1 to 9-n, and subscriber-side personal computers 10-1 to 10-n are installed in each subscriber's house. . The optical branching devices 6 and 13 may be installed on the center station side.

  The V-ONU remote control personal computer 1 stores the V-ONU remote control software in an internal storage unit (not shown). By executing the V-ONU remote control software, the V-ONU 8- Remote control commands corresponding to 1 to 8-n are periodically generated, and the remote control commands are output to the FSK modulator 2. The FSK modulator 2 performs FSK modulation on the remote control command from the V-ONU remote control personal computer 1 and sends it to the mixer 3.

  The mixer 3 outputs a mixed signal obtained by mixing the RF signal, which is a TV signal, and the FSK-modulated remote control command from the FSK modulator 2 to the optical transmitter 4. As of 2009, the TV signal (RF signal) input to the mixer 3 is in a state where analog waves and digital waves are mixed. The optical transmitter 4 converts the mixed signal from the mixer 3 into an optical signal and transmits the optical signal to the optical branching device 6 via the optical fiber 5. For example, the optical transmitter 4 adjusts the degree of optical modulation in accordance with a change in the mixed signal from the mixer 3, and then converts the mixed signal from the mixer 3 into an optical signal by a laser diode.

  The optical branching device 6 branches the optical signal transmitted by the optical fiber 5 by n (n is a natural number) and passes through each optical fiber 7-1 to 7-n to each V-ONU 8-1 to each subscriber house. Transmit to 8-n. Each V-ONU 8-1 to 8-n at each subscriber's house converts the received optical signal into an electrical signal, and the RF signal included in the electrical signal is transmitted via each coaxial cable at each subscriber's house. The data is transmitted to each television receiver 9-1 to 9-n at each subscriber's house. In addition, each V-ONU 8-1 to 8-n in each subscriber's house receives an FSK-modulated remote control command included in the electrical signal obtained by converting the received optical signal, and performs internal FSK demodulation. A remote control command is recognized by FSK demodulation by a device (not shown in FIG. 1).

  The remote control from the center station to the V-ONU is performed individually or simultaneously for the V-ONUs 8-1 to 8-n. In order to enable individual remote control, it is necessary to give unique identification information (for example, an address) to each of the V-ONUs 8-1 to 8-n. When individual remote control is performed, control is executed by specifying unique identification information (for example, an address) given to the V-ONU to be controlled.

  Therefore, in order to enable individual remote control, each of the V-ONUs 8-1 to 8-n is given unique identification information (for example, an address) at the factory, and then shipped, finally as shown in FIG. Installed at each subscriber's house.

Each D-ONU 11-1 to 11-n is housed inside the casing of each V / D-ONU 16-1 to 16-n together with each V-ONU 8-1 to 8-n (see FIG. 2 described later). reference). Each D-ONU 11-1 to 11-n and each subscriber personal computer 10-1 to 10-n are connected by an optical fiber. Each of the D-ONUs 11-1 to 11-n is a communication unit, and is used, for example, for Internet connection. The subscriber-side personal computers 10-1 to 10-n are connected to the optical fibers 12-1 to 12-n. The optical branching device 13, the optical fiber 14, and the communication system device 15 can be connected to a network such as the Internet.

  Next, V / D-ONUs 16-1 to 16-n and their constituent elements V-ONUs 8-1 to 8-n and D-ONUs 11-1 to 11-n will be described in detail with reference to FIGS. Explained.

  Each of the V / D-ONUs 16-1 to 16-n has an appearance as shown in FIG. 2, for example, and includes a box-shaped main body 20 and a lid 21 that covers an open portion of the main body 20 so as to be openable and closable. The optical fiber tray 22, the signal processing circuit unit 23, and the D-ONU 11 are accommodated. An optical fiber is introduced from the outside through an optical fiber insertion opening 24 provided on the side surface 20A of the main body 20, and the introduced optical fiber is wound around the optical fiber tray 22, and is provided at the end of the optical fiber. Is connected to the optical repeater adapter. In addition to the optical fiber insertion port 24, a coaxial cable connector 25 is also provided on the side surface 20A of the main body 20. The optical signal transmitted through the optical fiber is subjected to signal processing in the signal processing circuit unit 23, converted into an electrical signal (RF signal), and output from the coaxial cable connector 25 to the outside. In FIG. 2, in order to show that the signal processing circuit unit 23 is housed on the right side in the main body 20, the illustration of the optical fiber tray mounted on the upper part thereof is omitted. As with the left side of 20, an optical fiber tray is mounted.

  Each of the V-ONUs 8-1 to 8-n is a V-ONU having a schematic configuration shown in FIG. 3, for example. The V-ONU shown in FIG. 3 includes an input port (optical repeater adapter) IN, a light detection unit 26 having a function of converting an optical signal from the input port IN into an electric signal, and an electric power output from the light detection unit 26. A branching device 27 having a function of separating a signal into an RF signal which is a TV signal and an RF signal for FSK demodulation including a remote control command, and an RF signal which is a TV signal from the trunk line output of the branching device 27 is converted into the CATV band. A demultiplexer 28 that demultiplexes the signal into a signal in the CS / BS-IF band, an amplifier 29 that amplifies the signal in the CATV band, an amplifier 30 that amplifies the signal in the CS / BS-IF band, and an amplifier 29. A branching device 31 for branching the amplified CATV band signal, a branching device 32 for branching the CS / BS-IF band signal amplified by the amplifier 30, and a main line output of the distributor 31 are sent out. A mixer 33 that mixes the ATV band signal and the CS / BS-IF band signal sent from the output terminal of the trunk line of the distributor 32, and a mixed signal sent from the mixer 33 (CATV band signal and CS / Attenuator 34 for attenuating signals in the BS-IF band), and an output terminal for outputting the signal transmitted from the attenuator 34 as an RF output signal to a television receiver or the like (connector for coaxial cable connection) And.

  The V-ONU shown in FIG. 3 further receives a CATV band signal sent from the output terminal of the branch of the branching device 31, and a voltage corresponding to the level of the CATV band signal (hereinafter referred to as CATV detection voltage). And a CS / BS-IF band signal sent from the branch output terminal of the branching device 32 and a voltage corresponding to the level of the CS / BS-IF band signal (hereinafter, referred to as the CS / BS-IF band signal). CS / BS-IF detection voltage), an FSK demodulator 37 that FSK-demodulates an FSK-modulated remote control command supplied from the light detection unit 26, and a microcomputer (hereinafter referred to as a microcomputer). 38, an LED (Light Emitting Diode) drive unit 39 that outputs an LED drive signal according to the control of the microcomputer 38, and an LED 4 that is driven by the LED drive signal from the LED drive unit 39 0. The microcomputer 38 includes a nonvolatile memory (for example, a flash memory) 38A and an A / D converter (not shown).

  The microcomputer 38 is an example of a determination unit described in the claims, and is also an example of a change unit described in the claims. The nonvolatile memory 38A is an example of a storage unit described in the claims. The LED 40 is an example of a determination result output unit described in the claims. The light detection unit 26, the branching device 27, and the FSK demodulator 37 are an example of extraction means described in claims.

  The microcomputer 38 converts the CATV detection voltage sent from the detector 35 into a digital value by the A / D converter, and converts the CS / BS-IF detection voltage sent from the detector 35 by the A / D converter. Convert to digital value. Further, the microcomputer 38 determines whether the level of the CATV band signal is normal and whether the CATV determination reference value and the CS / BS-IF band signal level are normal. The determination reference value for CS / BS-IF that is used when determining is stored in the nonvolatile memory 38A in advance.

  The microcomputer 38 compares the A / D conversion value of the CATV detection voltage with the determination reference value for CATV, and if the A / D conversion value of the CATV detection voltage is equal to or less than the determination reference value for CATV, the level of the signal in the CATV band is It is determined to be normal, and if the A / D conversion value of the CATV detection voltage is not less than the determination reference value for CATV, it is determined that the signal level of the CATV band is not normal. Also, the microcomputer 38 compares the A / D conversion value of the CS / BS-IF detection voltage with the CS / BS-IF determination reference value, and the A / D conversion value of the CS / BS-IF detection voltage is the CS / BS-IF detection voltage. If it is below the BS-IF determination reference value, it is determined that the CS / BS-IF band signal level is normal, and the CS / BS-IF detection voltage A / D conversion value is the CS / BS-IF determination. If it is not less than the reference value, it is determined that the signal level of the CS / BS-IF band is not normal.

  Contrary to the above embodiment, the microcomputer 38 determines that the level of the signal in the CATV band is normal if the A / D conversion value of the CATV detection voltage is equal to or greater than the CATV determination reference value, and the CS / If the A / D conversion value of the BS-IF detection voltage is equal to or greater than the CS / BS-IF determination reference value, it may be determined that the signal level in the CS / BS-IF band is normal. Further, the microcomputer 38 stores the CATV upper limit determination reference value, the CATV lower limit determination reference value, the CS / BS-IF upper limit determination reference value, and the CS / BS-IF lower limit determination reference value in the nonvolatile memory 38A in advance. If the A / D conversion value of the CATV detection voltage is not less than the CATV lower limit determination reference value and not more than the CATV upper limit determination reference value, it is determined that the signal level of the CATV band is normal, and CS / BS− If the A / D conversion value of the IF detection voltage is not less than the CS / BS-IF lower limit judgment reference value and less than the CS / BS-IF upper limit judgment reference value, the signal level in the CS / BS-IF band is normal. You may make it determine with it.

  When the microcomputer 38 determines that both the CATV band signal level and the CS / BS-IF band signal level are normal, the microcomputer 38 determines that the RF output signal level is normal, and the CATV band signal. When it is determined that at least one of the signal level and the CS / BS-IF band signal level is not normal, it is determined that the RF output signal level is not normal. The microcomputer 38 controls the LED drive unit 39 according to the determination result of whether or not the level of the RF output signal is normal. For example, when the LED 40 is composed of a green LED and a red LED and a determination result that the level of the RF output signal is normal is obtained, only the green LED is turned on and the determination result that the level of the RF output signal is not normal If obtained, only the red LED may be lit. Further, the microcomputer 38 outputs a notification signal related to the determination result of whether or not the level of the RF output signal is normal in a format to which the address of the V-ONU is given. The notification signal is transmitted from the notification signal output terminal 41 to the D-ONU 11 (see FIG. 2), transmitted to the communication system device 15 of the center station by the D-ONU 11, and further from the communication system device 15 for V-ONU remote control. Sent to PC 1. Thereby, the V-ONU remote control personal computer 1 can grasp the determination result as to whether or not the level of the RF output signal is normal for each of the V-ONUs 8-1 to 8-n.

  In the above embodiment, the determination result of whether or not the level of the RF output signal is normal is output as the entire RF output signal, but may be output for each band. In this case, for example, the LED 40 is composed of a green LED for CATV, a red LED for CATV, a green LED for CS / BS-IF, and a red LED for CS / BS-IF, and the signal level of the CATV band, CS / BS- When the determination result that both the signal levels in the IF band are normal (= the determination result that the RF output signal level is normal) is obtained, only the green LED for CATV and the green LED for CS / BS-IF And the determination result that the level of the signal in the CATV band is not normal and the level of the signal in the CS / BS-IF band is normal (= one form of the determination result that the level of the RF output signal is not normal) is When obtained, only the red LED for CATV and the green LED for CS / BS-IF are turned on, the level of the signal in the CATV band is normal, and the CS / If a determination result that the signal level in the S-IF band is not normal (= one form of the determination result that the level of the RF output signal is not normal) is obtained, the green LED for CATV and the red LED for CS / BS-IF Only the light is turned on, and the determination result that the CATV band signal level and the CS / BS-IF band signal level are both not normal (= one form of the determination result that the RF output signal level is not normal) is obtained. In such a case, only the red LED for CATV and the red LED for CS / BS-IF may be lit. Also in this case, the microcomputer 38 may output a notification signal related to the determination result of whether or not the level of the RF output signal is normal in a format to which the V-ONU address is assigned. Then, the notification signal is transmitted from the notification signal output terminal 41 to the D-ONU 11 (see FIG. 2), transmitted by the D-ONU 11 to the communication system device 15 of the center station, and further from the communication system device 15 to the V-ONU remote. It is transmitted to the control personal computer 1. Thereby, the V-ONU remote control personal computer 1 can grasp the determination result as to whether or not the level of the RF output signal is normal for each of the V-ONUs 8-1 to 8-n.

  V-ONU shown in FIG. 3 is a determination reference value (for example, a determination reference value for CATV, a determination reference value for CS / BS-IF, or the like) used when determining whether or not the level of the RF output signal is normal. CATV upper limit determination reference value, CS / BS-IF upper limit determination reference value, CATV lower limit determination reference value, CS / BS-IF lower limit determination reference value, etc.) from the V-ONU remote control personal computer 1 The configuration is changed according to the control command. Specifically, the microcomputer 38 receives a determination reference value change command (a kind of remote control command) from the FSK demodulator 37, and stores the determination reference stored in the nonvolatile memory 38A based on the determination reference value change command. Rewrite the value.

  With this configuration, even when the wave number (the number of channels) of broadcast waves transmitted by the optical transmission system is changed in the future, it is possible to prevent erroneous determination in determining whether the RF output signal is normal. be able to. The V-ONU shown in FIG. 3 stores the judgment reference value in the non-volatile memory 38A. Therefore, even if the power supply to the V-ONU shown in FIG. A reference value can be stored.

  The V-ONU remote control personal computer 1 sends a determination reference value change command to the V-ONU 8-1 when necessary (for example, when the wave number (number of channels) of a broadcast wave transmitted by the optical transmission system is changed). Send to ~ 8-n.

  Here, FIG. 4 shows a data configuration example of the determination reference value change command. The determination reference value change command shown in FIG. 4 includes an STX that is a control code indicating the beginning of serial data, an identifier that indicates a determination reference value change command, a determination reference value, a checksum, and a control code that indicates the end of serial data. Are serial commands that are transmitted in the order of ETX. The checksum may be a checksum that covers all data before the checksum, or a checksum that targets only a part of the data before the checksum.

  When the V-ONU remote control personal computer 1 transmits the determination reference value change command shown in FIG. 4 to the V-ONUs 8-1 to 8-n, the determination reference value change command is sent to all the V-ONUs 8-1 to 8-n. Rewrite. In order to make it possible to change the determination reference value individually or for each group for the V-ONUs 8-1 to 8-n, for example, the determination reference value change command may have a data structure shown in FIG. . When the determination reference value is changed for each group, for example, the V-ONU remote control personal computer 1 stores the correspondence between addresses and groups for the V-ONUs 8-1 to 8-n. It is good to.

  The determination reference value change command shown in FIG. 5 includes an STX that is a control code indicating the beginning of serial data, an address for specifying a V-ONU whose determination reference value is to be changed, that is, a V-ONU that is a determination reference value change target. This is a serial command in which data is transmitted in the order of address, identifier indicating a determination reference value change command, determination reference value, checksum, and control code indicating the end of serial data.

Checksum contained in the judgment reference value change command may be a checksum for all data prior to checksum or checksum shall be the subject only a portion of data prior to checksum.

  Next, FIG. 6 shows a schematic configuration of an optical transmission system for CATV according to the second embodiment of the present invention. In FIG. 6, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

The optical transmission system shown in FIG. 6 includes a V-ONU remote control personal computer 1, an FSK modulator 2, a mixer 3, an optical transmitter 4, an optical fiber 5, an optical splitter 6, and an optical fiber. 7-1 to 7-n, V-ONUs 8-1 to 8-n having a remote control function, and television receivers 9-1 to 9-n. That is, the optical transmission system shown in FIG. 6 is different from the optical transmission system shown in FIG. 1 in that the subscriber-side personal computers 10-1 to 10 -n , D-ONUs 11-1 to 11-n, and optical fibers 12-1 to 12-1. 12-n, the optical branching device 13, the optical fiber 14, and the communication system device 15 are removed.

  In the optical transmission system shown in FIG. 6, each of the V-ONUs 8-1 to 8-n corresponds to the optical terminal device according to the present invention. Moreover, the external appearance examples of the optical terminal devices (V-ONUs 8-1 to 8-n) used in the optical transmission system shown in FIG. 6 are almost the same as those shown in FIG. Will be removed. The schematic configuration example of the optical terminal devices (V-ONUs 8-1 to 8-n) used in the optical transmission system illustrated in FIG. 6 is substantially the same as the configuration illustrated in FIG. The output terminal 41 is removed, and the microcomputer 38 does not output a notification signal related to the determination result as to whether or not the level of the RF output signal is normal.

  Therefore, the optical transmission system shown in FIG. 6 is similar to the optical transmission system shown in FIG. 1 even if the wave number (number of channels) of broadcast waves transmitted by the optical transmission system is changed in the future. It is possible to prevent erroneous determination in determining whether or not is normal.

  The optical terminal device according to the present invention and the optical transmission system according to the present invention are not limited to the configurations of the first and second embodiments described above.

  For example, the V-ONU shown in FIG. 3 has a configuration in which a CATV band signal and a CS / BS-IF band signal are individually detected, but instead of the configuration, a signal or attenuator output from the mixer 33 is used. The signal output from 34 may be detected, and the detection result may be used to determine whether the level of the RF output signal is normal.

  Further, the V-ONU shown in FIG. 3 sends the determination result of whether the level of the RF output signal is normal to the lighting color of the LED 40 and the personal computer 1 for remote control via the D-ONU. The output is based on the notification signal output or the lighting color of the LED 40. Instead of this configuration, for example, the determination result as to whether the level of the RF output signal is normal is the voice output and the D-ONU. It may be output by a notification signal output or a voice output to the V-ONU remote control personal computer 1 via.

1 V-ONU PC for remote control 2 FSK modulator 3 Mixer 4 Optical transmitter 5 Optical fiber 6 Optical splitter 7-1 to 7-n Optical fiber 8-1 to 8-n V-ONU (according to the present invention Example of optical terminal device)
9-1 to 9-n TV receiver 10 -1 to 10 -n subscriber side personal computer 11, 11-1 to 11-n D-ONU
12-1 to 12-n Optical fiber 13 Optical splitter 14 Optical fiber 15 Communication system equipment 16-1 to 16-n V / D-ONU
20 Main Body 20A Side of Main Body 21 Lid 22 Optical Fiber Tray 23 Signal Processing Circuit Unit 24 Optical Fiber Insertion Port 25 Connector for Coaxial Cable Connection 26 Photodetector 27 Branching Unit 28 Splitter 29, 30 Amplifier 31, 32 Branching Unit 33 Mixing Unit 34 attenuator 35, 36 detector 37 FSK demodulator 38 microcomputer 38A nonvolatile memory 39 LED drive unit 40 LED
41 Notification signal output terminal

Claims (3)

In an optical terminal device that inputs an optical signal and outputs an RF output signal based on the optical signal,
Determining means for determining whether the level of the RF output signal is normal;
Storage means for storing a determination reference value used for determination by the determination means;
A determination result output means for outputting a determination result of the determination means;
Extraction means for extracting a determination reference value change command for instructing change of the determination reference value from the optical signal;
Changing means for changing the determination reference value stored in the storage means based on the determination reference value change command not related to the determination result of the determination means, not based on the determination result of the determination means; An optical terminal device.   The optical terminal device according to claim 1, wherein the storage unit is a nonvolatile memory. The optical terminal device according to claim 1, a remote control device for remotely controlling the optical terminal device, and an optical transmission device,
The remote control device outputs a determination reference value change command for instructing change of the determination reference value,
The optical transmission system, wherein the optical transmission device converts an electrical signal including the determination reference value change command into an optical signal, and transmits the optical signal to the optical terminal device.

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