Remote devices and transmission systems

Abstract

It efficiently stores electricity using weak light, enabling data transmission. [Solution] The remote device 2 comprises a photoelectric converter 202 that converts light output from the center device 1 via an optical fiber 4 into electricity, a power storage unit 204 that stores the converted electricity, a light source 208 that transmits transmission data to the center device as transmitted light, a start control unit 205 that starts the control unit 206 when the amount of power stored in the power storage unit 204 reaches a predetermined amount of power, the control unit 206 that controls the light source 208, and a stop unit 230 that monitors the state of the control unit 206 and stops the control unit 206 according to the state.

Description

Technical Field

[0001] The present disclosure relates to a remote device and a transmission system.

Background Art

[0002] As a conventional transmission device using optical fiber power feeding, an image transmission system is proposed in Non-Patent Document 1. This is a technology that connects two optical fibers, one for optical power feeding and one for communication, and can transmit images to a remote location approximately 10 km away.

[0003] Further, as a network system using optical fiber power feeding, a sensor network is proposed in Non-Patent Document 2. In the sensor network, a power feeding light source for supplying power is installed on the center side, an optical signal from the power feeding light source is transmitted to a plurality of node devices installed in remote locations to supply power, and sensors are driven to acquire sensor information. The power feeding light source on the center side is used for downlink communication to the node devices and uplink communication from the node devices.

[0004] Non-Patent Document 3 proposes an optically powered optical path switching device for PON (Passive Optical Network) protection. This is a technology in which two optical fibers, a normal path and a redundant path, are prepared between a communication building and an optical splitter installed outdoors, and when a disconnection occurs in the normal path, an optical switch is operated to switch to the redundant path.

Prior Art Literature

Non-Patent Literature

[0005]

Non-Patent Document 1

Non-Patent Document 2

[0006] Non-patent document 1 states that 75mW of optical power is required to supply a remote device. Considering that the optical intensity used in subscriber communications is typically a few mW or less, this is a significantly higher optical intensity, and there are problems with using existing optical communication networks for optical power supply.

[0007] Non-Patent Literature 2 describes how, in uplink communication from a node device, an optical signal is transmitted that is modulated using a reflector called a MEMS optical modulator, which is an optical signal output from a power supply light source on the center side. Non-Patent Literature 2 describes how using a MEMS optical modulator reduces power consumption, allowing operation with several hundred μW of power. In this case, the required optical power supply is about 1 mW, and it is possible to use existing optical communication networks for optical power supply. However, the most widespread optical communication network is the PON network for subscriber communications. The optical power that can be supplied from unused optical splitter ports in this PON network is only about 0.1 mW, and there is a problem in that MEMS optical modulators cannot be used as a power supply source via optical power supply.

[0008] Non-patent document 3 proposes an optical path switching device that can operate with a weak optical power supply of about 0.1 mW, which is used in subscriber communications. However, data transmission requires a control device with high processing power and high power consumption.

[0009] This disclosure is made in view of the above circumstances, and the purpose of this disclosure is to provide a technology that enables efficient storage of electricity using weak light and facilitates data transmission. [Means for solving the problem]

[0010] One aspect of the present disclosure is a remote device comprising: a photoelectric converter that converts light output from a central device via an optical fiber into electricity; a power storage unit that stores the converted electricity; a light source that transmits transmission data to the central device as transmitted light; a startup control unit that starts up a control unit when the amount of power stored in the power storage unit reaches a predetermined amount of power; a control unit that controls the light source; and a stop unit that monitors the state of the control unit and stops the control unit according to the state.

[0011] One aspect of the present disclosure is a transmission system comprising a central device and a remote device, wherein the central device includes a first light source that outputs light to the remote device via an optical fiber, and the remote device includes a photoelectric converter that converts the light output from the central device into electricity, a power storage unit that stores the converted electricity, a second light source that transmits transmission data to the central device as transmission light, a startup control unit that starts up a control unit when the amount of power stored in the power storage unit reaches a predetermined amount of power, a control unit that controls the second light source, and a stop unit that monitors the state of the control unit and stops the control unit according to the state. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide a technology that efficiently stores electricity using weak light and enables data transmission. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 shows an example of the configuration of the transmission system according to the embodiment. [Figure 2] Figure 2 shows an example of the configuration of the reset control unit of the embodiment. [Figure 3] Figure 3 is a flowchart showing an example of processing by the remote device of the embodiment. [Figure 4] Figure 4 shows an example of a hardware configuration. [Modes for carrying out the invention]

[0014] Embodiments of this disclosure will be described with reference to the attached drawings. The embodiments described below are examples of the disclosure, and the disclosure is not limited to these embodiments. In this specification and in the drawings, components with the same reference numerals refer to the same components.

[0015] Figure 1 is a diagram showing a configuration example of a transmission system according to an embodiment of the present invention. The illustrated transmission system includes a center apparatus 1 (in-station node) and a remote apparatus 2 (out-of-station node). An upstream center apparatus 1 and a plurality of downstream remote apparatuses 2 are connected via an optical fiber 4. In the present embodiment, the direction from the remote apparatus 2 toward the center apparatus 1 is described as "upstream direction", and the direction from the center apparatus 1 toward the remote apparatus 2 is described as "downstream direction".

[0016] The center apparatus 1 is installed in an environment where power can be secured (for example, inside a communication building), and performs optical fiber power feeding. Specifically, the center apparatus 1 outputs power feeding light to the remote apparatus 2 via the optical fiber 4.

[0017] The illustrated center apparatus 1 includes a light source 101 that outputs light, an optical coupler 102, a photoelectric converter 103, and a control unit 104. Note that light is also referred to as an optical signal in the following description.

[0018] The light source 101 (first light source) outputs light to the remote apparatus 2 via the optical fiber 4. The light source 101 is a power feeding light source for feeding power to the remote apparatus 2. The light source 101 is, for example, a laser diode, and emits laser light. Light emitted from the light source 101 is input to the optical fiber 4 via the optical coupler 102. Note that the center apparatus 1 may transmit a downstream optical signal (hereinafter, "downstream signal") using the power feeding light source 101.

[0019] The optical coupler 102 outputs the light (power feeding light) output from the light source 101 to the remote apparatus 2 via the optical fiber 4. The optical coupler 102 also outputs an upstream optical signal (hereinafter, "upstream signal") transmitted from the remote apparatus 2 via the optical fiber to the photoelectric converter 103. By using the optical coupler 102, the center apparatus 1 and the remote apparatus 2 can be connected with a single optical fiber 4. For the optical coupler 102, for example, a wavelength multiplexing / demultiplexing coupler can be used.

[0020] The photoelectric converter 103 (light receiver) receives an upstream signal output from the remote device 2 via the optical fiber 4, converts it into an electrical signal, and outputs the electrical signal to the control unit 104. The upstream signal according to the present embodiment may include, for example, data acquired by a driving unit 207 such as a sensor, the stored power amount of a power storage unit 204 of the remote device 2, and the like. A light receiving element such as a photodiode is used for the photoelectric converter 103.

[0021] The control unit 104 (first control unit) executes various types of control. For example, the control unit 104 may receive the upstream signal output from the photoelectric converter 103 via the signal line 107, and transmit data included in the upstream signal to the receiving device 3. The receiving device 3 manages data transmitted in the transmission system.

[0022] Furthermore, the control unit 104 may send a modulation signal to the light source 101, and superimpose a control signal (downstream signal) for the remote device 2 onto the power feeding light output from the light source 101. Examples of the control signal include an inquiry about the stored power amount of the power storage unit 204.

[0023] Note that an optical splitter 5 may be disposed between the center device 1 and the remote device 2.

[0024] The remote device 2 is connected to the center device 1 via the optical fiber 4, and is a device capable of storing power by optical power feeding. Therefore, the remote device 2 can be installed in a place where no power supply is available.

[0025] The illustrated remote device 2 includes an optical coupler 201, a photoelectric converter 202, a backflow prevention unit 203, a power storage unit 204, a startup control unit 205, a control unit 206, a driving unit 207, a light source 208, and a reset control unit 230 (stop unit).

[0026] The optical coupler 201 outputs light input from the center device 1 via the optical fiber 4 to the photoelectric converter 202. The optical coupler 201 also outputs the upstream signal (data transmission light) output from the light source 208 to the center device 1 via the optical fiber 4. For example, a wavelength multiplexing / demultiplexing coupler can be used as the optical coupler 201.

[0027] The photoelectric converter 202 converts the light output from the center device 1 into electricity via the optical coupler 201. The light output from the center device 1 may also be light from an unused port of the optical splitter 5 located between the center device 1 and the remote device 2. The photoelectric converter 202 uses a photoelectric conversion element capable of receiving the wavelength of the laser light emitted by the light source 101. The photoelectric conversion element can be an easily available element suitable for the long wavelength band of 1300nm to 1600nm used for communication, such as indium gallium arsenide, with an open-circuit voltage of 5V or less and a conversion efficiency of about 30%. The wavelength of the light emitted by the light source 101 of the center device 1 is set to a wavelength corresponding to the photoelectric conversion element of the photoelectric converter 202 used. The photoelectric conversion element is, for example, an optical power supply converter. The power of the laser light from the optical fiber 4 that can be used as optical power supply varies depending on the device used.

[0028] The electricity converted by the photoelectric converter 202 is stored in the energy storage unit 204 via the reverse current prevention unit 203. A Schottky barrier diode or the like can be used in the reverse current prevention unit 203.

[0029] The energy storage unit 204 stores the electricity (electrical energy) converted by the photoelectric converter 202. For example, an electrolytic capacitor can be used in the energy storage unit 204. Furthermore, the supply voltage to each active element can be adjusted as appropriate using a boost circuit (such as a DC / DC converter).

[0030] The startup control unit 205 monitors the amount of charge (storage energy) stored in the energy storage unit 204, and starts the control unit 206 when the amount of charge stored in the energy storage unit 204 reaches a predetermined amount of energy. In other words, when the predetermined amount of charge is reached, the startup control unit 205 starts supplying power to the control unit 206 and starts the control unit 206. The startup control unit 205 is installed between the energy storage unit 204 and the control unit 206 and controls the power supply from the energy storage unit 204 to the control unit 206. Specifically, the startup control unit 205 controls the on / off state so that power is supplied to the control unit 206 only when necessary. The startup control unit 205 may stop supplying power to the control unit 206 when it receives a reset signal (stop signal), which will be described later, from the reset control unit 230.

[0031] A load switch IC (see, for example, Non-Patent Document 4) can be used in the startup control unit 205. The control input of the load switch IC is controlled to obtain a desired voltage by dividing the voltage of the energy storage unit 204 with a resistor. This makes it possible to start the control unit 206 at the desired voltage.

[0032] The control unit 206 (second control unit) controls the drive unit 207 and the light source 208. The control unit 206 is connected to the drive unit 207 and the light source 208 via power lines 211, 212 and signal lines 222, 223. The control unit 206 is connected to the reset control unit 230 via signal line 224. For example, a microprocessor can be used for the control unit 206.

[0033] Signal line 224 transmits a signal indicating the status of the control unit 206, which is output from the control unit 206 to the reset control unit 230. In other words, the control unit 206 can notify the reset control unit 230 of its own status (operating, stopped) via signal line 224.

[0034] HIGH and LOW level signals may be used to indicate the state of the control unit 206. For example, when the control unit 206 is started by the startup control unit 205, it may set the signal output to the reset control unit 230 to a HIGH level and supply power to the reset control unit 230. The control unit 206 may also set the signal on the signal line 224 to a LOW level after the transmission of the data transmission light, which will be described later.

[0035] The control unit 206 sets the signal on signal line 224 to a HIGH level, then generates the necessary voltages for the drive unit 207 and light source 208 using a boost circuit (such as a DC / DC converter), and supplies them to the drive unit 207 and light source 208, respectively, via power lines 211 and 212.

[0036] The drive unit 207 is, for example, a sensor that acquires predetermined data. The illustrated drive unit 207 is electrically connected to the control unit 206 via signal line 222 and power line 211, and is driven using the power stored in the energy storage unit 204. The drive unit 207 acquires predetermined data according to the control of the control unit 206 and sends the acquired data to the control unit 206.

[0037] The drive unit 207 may be, for example, a sensor that detects predetermined information in accordance with the control of the control unit 206 and transmits the detected information to the control unit 206. A wide variety of sensor devices can be used as the sensor, such as a temperature sensor, humidity sensor, motion sensor, tilt sensor, water level sensor, etc. The drive unit 207 may also be an imaging device (e.g., an image sensor) that captures video data of the inside or surrounding area of ​​an underground manhole, utility pole, etc., where the remote device 2 is located. The drive unit 207 sends the acquired data to the control unit 206 via the signal line 222.

[0038] When the control unit 206 receives data from the drive unit 207, it starts supplying power to the light source 208 via the power line 212 to start the light source 208, and also sends a modulation signal to the light source 208 via the signal line 223 to generate the transmission light (upstream signal) of the data to be transmitted.

[0039] The light source 208 (second light source) is an uplink communication mechanism that transmits the data acquired by the drive unit 207 as transmitted light to the center device 1. The illustrated light source 208 is electrically connected to the control unit 206 via the signal line 223 and the power line 212, and is driven using the power stored in the power storage unit 204. The light source 208 generates an uplink signal to be transmitted to the center device 1 using the light from the light source 208, in accordance with the control of the control unit 206. Specifically, the light source 208 is assumed to be an internally modulated laser equipped with a modulation function (modulator). The light source 208 modulates the light output from the light source 208 in accordance with the control of the control unit 206 to generate data transmission light (modulated light). In the illustrated example, a direct modulation method in which the light source 208 has a modulation function is used, but an external modulation method in which the light source 208 and the modulator are separated may also be used.

[0040] The transmitted light (upstream signal) output from the light source 208 is output to the center device 1 via the optical coupler 201 and the optical fiber 4. The transmitted light input to the center device 1 is input to the photoelectric converter 103 via the optical coupler 102. The photoelectric converter 103 converts the transmitted light transmitted from the remote device 2 into an electrical signal (data) and outputs it to the control unit 104. As a result, the control unit 104 can receive the data acquired by the drive unit 207 of the remote device 2.

[0041] The control unit 206 may set the signal on signal line 224 to a LOW level after transmitting the data transmission light. Also, the signal on signal line 224 (the signal output from the control unit 206 to the reset control unit 230) may be at a LOW level if the control unit 206 stops. For example, if the power consumption of the control unit 206 becomes high, the control unit 206 may stop operating (down) due to insufficient voltage. In this embodiment, when the control unit 206 stops, the signal on signal line 224 becomes at a LOW level.

[0042] The reset control unit 230 (stop unit) monitors the state of the control unit 206 and stops the control unit 206 according to the state. Specifically, the reset control unit 230 may monitor a signal indicating the state of the control unit 206 and send a reset signal to the start control unit 205 according to the signal. The reset signal is a stop signal for stopping the control unit 206. In this embodiment, the reset control unit 230 sends a reset signal to the start control unit 205 and causes the start control unit 205 to stop the control unit 206. For example, the reset control unit 230 may constantly monitor the signal line 224 and, upon detecting that the signal on the signal line 224 has become LOW level (stop state), send a reset signal to the start control unit 205 via the signal line 221, causing the start control unit 205 to stop supplying power to the control unit 206.

[0043] When the startup control unit 205 receives a reset signal from the reset control unit 230 via the signal line 221, it stops supplying power to the control unit 206. This stops some functions of the remote device 2 (control unit 206, drive unit 207, light source 208, and reset control unit 230), preventing unnecessary power consumption during energy storage. The reset control unit 230 stops receiving power from the control unit 206 when the signal on the signal line 224 reaches a LOW level, but it operates for a short time using the power stored in the energy storage unit 232 to transmit the reset signal, and then stops operating.

[0044] Furthermore, if the control unit 206 stops operating due to insufficient voltage, the signal on signal line 224 will become LOW. Since the reset control unit 230 monitors the signal on signal line 224, when it detects a LOW level signal, it sends a reset signal to the start control unit 205, which can stop some functions of the remote device 2.

[0045] When a load switch IC (for example, Non-Patent Document 4) is used as the startup control unit 205, the reset control unit 230 can reset the startup control unit 205 by, for example, setting the control input terminal of the load switch IC to 0V (zero volts), i.e., interrupting the circuit. The reset of the startup control unit 205 means that the startup control unit 205 stops supplying power to the control unit 206, thereby shutting down the control unit 206.

[0046] Figure 2 shows an example configuration of the reset control unit 230. The illustrated reset control unit 230 comprises a reverse current prevention unit 231, a power storage unit 232 (another power storage unit), and a control unit 233 (another control unit). The power storage unit 232 stores electricity supplied from the power storage unit 204 via the control unit 206. The control unit 233 is driven by the power of the power storage unit 232, monitors a signal indicating the status of the control unit 206, and sends a reset signal to the start control unit 205 according to the signal.

[0047] Specifically, power is supplied to the reset control unit 230 when the signal on signal line 224 is set to a HIGH level. The supplied power is stored in the energy storage unit 232 via the reverse current prevention unit 231 and supplied to the control unit 233. A Schottky barrier diode or the like can be used for the reverse current prevention unit 231.

[0048] The control unit 233, which is activated by the power supply, monitors the signal on signal line 224 via signal line 234. Signal line 234 is a signal line that connects the control unit 233 and signal line 224, and is a signal line for monitoring the signal on signal line 224 (the state of the control unit 206).

[0049] When the control unit 233 detects that the signal on signal line 224 has become LOW, it sends a reset signal to the startup control unit 205 via signal line 221, and controls the startup control unit 205 to stop the control unit 206. As mentioned above, the control unit 233 may also set the control input terminal of the load switch IC (startup control unit 205) to 0V (zero volts) as the reset signal.

[0050] Alternatively, after the signal on signal line 224 goes to a LOW level and power supply to the reset control unit 230 stops, the control unit 233 may use the remaining power in the energy storage unit 232 to set the signal on signal line 221 to a HIGH level and transmit a reset signal to the start control unit 205. In this case, the energy storage unit 232 supplies power to the control unit 233 for transmitting the reset signal. The power for transmitting the reset signal is, for example, the power required for the control unit 233 to set signal line 221 to a HIGH level and reset the start control unit 205.

[0051] Figure 3 is a flowchart showing an example of the transmission process of the remote device 2 in this embodiment.

[0052] Furthermore, power supply light from the central device 1 is constantly input to the remote device 2, and electricity is continuously stored in the power storage unit 204.

[0053] The startup control unit 205 monitors the amount of energy stored in the energy storage unit 204 (S11), and if the amount of energy stored reaches a predetermined amount (S12: YES), it starts supplying power to the control unit 206 and starts up the control unit 206 (S13). If the amount of energy stored is less than the predetermined amount (S12: NO), the startup control unit 205 returns to S11 and monitors the amount of energy stored in the energy storage unit 204.

[0054] The activated control unit 206 sets the signal on signal line 224 to a HIGH level and supplies power to the reset control unit 230 (S14). As a result, the reset control unit 230 starts up and begins monitoring signal line 224.

[0055] The control unit 206 then supplies power to the drive unit 207 to start it up. The control unit 206 controls the drive unit 207 to acquire data (S15). The data may be, for example, sensor data detected and imaged by the drive unit 207, such as a sensor. The control unit 206 supplies power to the light source 208 to control it, generates data transmission light, and transmits the transmission light to the center device 1 (S16). After transmitting the data transmission light, the control unit 206 sets the signal on the signal line 224 to a LOW level (S17).

[0056] When the signal on signal line 224 is set to a LOW level, the reset control unit 230 sends a reset signal to the startup control unit 205 (S18). Upon receiving the reset signal, the startup control unit 205 stops supplying power to the control unit 206 and returns to S11 (S19). By stopping the power supply to the control unit 206, the operation of the control unit 206, the drive unit 207, the light source 208, and the reset control unit 230 is stopped. This prevents unnecessary power consumption during energy storage.

[0057] Furthermore, if the power consumption of the control unit 206 becomes too high, the control unit 206 may stop operating due to insufficient voltage. In this embodiment, when the control unit 206 stops, the signal on signal line 224 goes to a LOW level. Therefore, the reset control unit 230, which monitors the signal on signal line 224, detects that the signal has gone to a LOW level and sends a reset signal to the start control unit 205 (S18), causing the start control unit 205 to stop supplying power to the control unit 206 (S19).

[0058] Thus, in this embodiment, the operating status of the control unit 206 is monitored, and even if the control unit 206 stops operating due to a voltage drop in an unforeseen situation, the startup control unit 205 can be reset, and the necessary power storage can be restarted with some functions in the remote device 2 stopped. In other words, in this embodiment, it is possible to avoid a situation where the weak power supply and the power consumption of the stopped control unit 206 balance out, making it impossible to restart the control unit 206.

[0059] The remote device 2 of this embodiment described above comprises a photoelectric converter 202 that converts light output from the center device 1 via an optical fiber 4 into electricity, a power storage unit 204 that stores the converted electricity, a light source 208 that transmits transmission data as transmission light to the center device 1, a startup control unit 205 that starts up the control unit 206 when the amount of power stored in the power storage unit 204 reaches a predetermined amount of power, the control unit 206 that controls the light source 208, and a reset control unit 230 that monitors the state of the control unit 206 and stops the control unit 206 according to the state.

[0060] The transmission system of this embodiment is a transmission system comprising a central device 1 and a remote device 2, wherein the central device 1 includes a first light source 101 that outputs light to the remote device 2 via an optical fiber 4, and the remote device 2 includes a photoelectric converter 202 that converts the light output from the central device 1 into electricity, a power storage unit 204 that stores the converted electricity, a second light source 208 that transmits transmission data to the central device as transmitted light, a start control unit 205 that starts the control unit when the amount of power stored in the power storage unit 204 reaches a predetermined amount of power, a control unit 206 that controls the second light source 208, and a reset control unit 230 that monitors the state of the control unit 206 and stops the control unit 206 according to the state.

[0061] As a result, in this embodiment, power can be efficiently stored using weak light, and data can be transmitted from the remote device 2 to the central device 1. In other words, in this embodiment, the light loss of the light source can be reduced, and energy efficiency can be improved.

[0062] Specifically, in this embodiment, once sufficient power is secured in the energy storage unit 204, the control unit 206 and the like are activated, allowing the remote device 2 to be driven even with weak optical power supplied from, for example, an unused port of an optical splitter in a PON network. This makes it possible to use the control unit 206, which has high power consumption and processing capacity, to realize diverse data transmission using weak optical power supplied through an existing optical communication network.

[0063] Thus, in this embodiment, it is possible to prevent a decrease in energy efficiency due to unnecessary losses, efficiently store energy using weak optical power supply that can be supplied even in existing optical access networks, drive the remote device 2 without consuming unnecessary power during storage, and collect information from the drive unit 207.

[0064] Furthermore, in this embodiment, the reset control unit 230 monitors the state of the control unit 206 and stops the control unit 206 according to the state. As a result, even if the control unit 206 stops operating due to a voltage drop caused by an increase in the power consumption of the control unit 206, the reset control unit 230 controls the start control unit 205 to stop the power supply to the control unit 206. This makes it possible to restart the storage of the necessary power while some functions within the remote device 2 are stopped. In other words, in this embodiment, it is possible to avoid a situation where the weak power supply balances with the power consumption of the stopped control unit 206, making it impossible to restart the control unit 206.

[0065] The control unit 104 of the central device 1 and the control units 206 and 233 of the remote device 2 described above can use, for example, a general-purpose computer system as shown in Figure 4. The illustrated computer system comprises a CPU (Central Processing Unit, processor) 901, memory 902, storage 903 (HDD: Hard Disk Drive, SSD: Solid State Drive), communication device 904, input device 905, and output device 906. The memory 902 and storage 903 are storage devices. In this computer system, the functions of the control unit 104 or control unit 206 are realized when the CPU 901 executes a predetermined program loaded onto the memory 902.

[0066] The programs of control unit 104 or control units 206 and 233 can be stored on computer-readable recording media such as HDDs, SSDs, USB (Universal Serial Bus) memory, CDs (Compact Discs), and DVDs (Digital Versatile Discs), or distributed over a network. Computer-readable recording media are, for example, non-transitory recording media.

[0067] This disclosure is not limited to the embodiments described above, and numerous modifications are possible within the scope of its essence. [Explanation of symbols]

[0068] 1: Center device 101: Light source (1st light source) 102: Optical coupler 103: Photoelectric Converter 104: Control Unit (First Control Unit) 2: Remote device 201: Optical coupler 202: Photoelectric Converter 203: Backflow prevention unit 204: Energy Storage Unit 205: Startup Control Unit 206: Control Unit (Second Control Unit) 207: Drive unit (sensing unit) 208: Light source (second light source) 230: Reset control unit (stop unit) 231: Backflow prevention unit 232: Energy storage unit (other energy storage unit) 233: Control Unit (Other Control Units) 3: Receiving device 4: Fiber optic 5: Optical Splitter

Claims

1. A photoelectric converter that converts light output from the central device via optical fiber into electricity, A power storage unit for storing the converted electricity, A light source that transmits the transmission data as transmission light to the central device, A startup control unit activates the control unit when the amount of stored energy in the aforementioned energy storage unit reaches a predetermined amount of energy. The control unit that controls the light source, The system includes a stop unit that monitors the state of the control unit and stops the control unit according to the state. Remote control device.

2. The stop unit monitors a signal indicating the status of the control unit and sends a stop signal to the start control unit in accordance with the signal. When the startup control unit receives the stop signal, it stops supplying power to the control unit. The remote device according to claim 1.

3. The aforementioned stopping unit is Another energy storage unit that stores electricity supplied to the energy storage unit via the control unit, The system includes another control unit which is driven by the power of the other energy storage unit, monitors a signal indicating the state of the control unit, and sends a stop signal to the start control unit in response to the signal, When the startup control unit receives the stop signal, it stops supplying power to the control unit. The remote device according to claim 1.

4. The control unit, When the startup control unit starts up, it sets the signal output to the stop unit to a HIGH level and supplies power to the stop unit. After transmitting the aforementioned light, set the signal to a LOW level. The remote device according to claim 1.

5. The signal output from the control unit to the stop unit becomes LOW level when the control unit stops. The remote device according to claim 1.

6. The light output from the central device is the light output from an unused port of an optical splitter located between the central device and the remote device. The remote device according to claim 1.

7. A transmission system comprising a central device and a remote device, The aforementioned center device is The system includes a first light source that outputs light to the remote device via an optical fiber, The remote device is A photoelectric converter that converts light output from the aforementioned center device into electricity, A power storage unit for storing the converted electricity, A second light source that transmits the transmission data as transmission light to the central device, A startup control unit activates the control unit when the amount of stored energy in the aforementioned energy storage unit reaches a predetermined amount of energy. The control unit that controls the second light source, The system includes a stop unit that monitors the state of the control unit and stops the control unit according to the state. Transmission system.

8. The stop unit monitors a signal indicating the status of the control unit and sends a stop signal to the start control unit in accordance with the signal. When the startup control unit receives the stop signal, it stops supplying power to the control unit. The transmission system according to claim 7.

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