Method for solving working problem of POE camera in power-free and network-free environment

Abstract

The invention discloses a method for solving the problem that a POE camera works in a non-power and non-network environment, and the method comprises the following steps: firstly, equipment detects whether a powered body exists or not, the equipment judges whether the powered body exists or not by detecting the resistance-capacitance value between a power output line pair, and only when the powered body is detected, the equipment carries out the next operation; and the equipment determines the power consumption of the supplied body, and determines the power level of the supplied body by detecting the output current of the power supply. DC12V / DC24V is boosted to a POE standard DC51V, so that the DC12V provided by solar energy is boosted to about 51V; and meanwhile, POE protocol conversion is carried out on a communication network provided by the 4G communication module and a 51V power supply, so that a novel device with POE standard output and powered by solar energy is finally formed, the problem that the POE camera works in a network-free and power-free environment is solved, and the deployment and control cost of the POE camera in environments such as a river channel, a reservoir and a forest is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of POE cameras, and specifically to a method for a POE camera to work in an environment without power and network. Background Art

[0002] The POE standard defines two methods for delivering direct current to POE-compatible devices using the transmission cables of Ethernet: one is called "Mid-Span", which uses the unused spare pairs in the Ethernet cable to transmit direct current. The corresponding Endpoint PSE supports POE-capable Ethernet switches, routers, hubs, or other network switching devices. Power is supplied through pairs 45 and 78 of the network cable, that is: power is supplied through the spare lines. The other method is "End-Span", which transmits direct current simultaneously on the cores used for transmitting data, and its power transmission uses a different frequency from the Ethernet data signal. Power is supplied through pairs 12 and 36 of the network cable, that is: power is supplied through the signal lines.

[0003] Since the DC current and the data frequency do not interfere with each other, current and data can be transmitted simultaneously on the same pair of wires. In fact, for the cable, it can be regarded as a kind of "multiplexing" technology. The voltage provided by PoE is below 57V, which belongs to "safe voltage" and meets the safety regulations requirements. Studying the power supply method of POE, it can be seen that there are two key issues to consider during the power supply process. One is the identification of PD devices, and the other is the capacity of the UPS in the system;

[0004] Currently, the Chinese invention with the publication number: CN103516382B discloses a security system and method using a wireless adapter and a PoE camera. Existing POE cameras can be deployed and applied at low cost and quickly in field scenarios such as river monitoring, forest fire prevention, and temporary deployment. POE cameras have a variety of functional models and powerful functions, so they have been widely used in many fields such as public security, forestry, transportation, and water conservancy.

[0005] However, when such cameras work, they need to provide power, a wired (or WIFI) network, and a conventional solar panel power supply system. Since the conventional solar panel power supply system mostly uses a DC12V / DC24V voltage output, the voltage is insufficient. Therefore, the cost of laying cables and pulling electricity for equipment control points in environments such as rivers, reservoirs, and forests is extremely high, resulting in insufficient or even lack of security control in such environments.

[0006] Therefore, a method for a POE camera to work in an environment without power and network is proposed to solve this problem. Summary of the Invention

[0007] The object of the present invention is to provide a method for solving the problem of POE cameras working in a power - and network - free environment. The conventional solar panel power supply system mostly uses DC12V / DC24V voltage output, resulting in insufficient voltage. Therefore, the cost of laying cables and pulling electricity for equipment control points in environments such as rivers, reservoirs, and forests is extremely high, leading to insufficient or even lack of security control in such environments.

[0008] To achieve the above object, the present invention provides the following technical solution: A method for solving the problem of POE cameras working in a power - and network - free environment, including the following steps:

[0009] Step 1: Detection stage: First, the device detects whether the powered object exists. The device determines whether the powered object exists by detecting the resistance - capacitance value between the power output lines. Only when the powered object is detected will the device proceed to the next step.

[0010] Step 2: Classification stage: Then, the device determines the power consumption of the powered object. The device determines the power level of the powered object by detecting the power output current.

[0011] Step 3: Startup stage: After that, the device supplies power to the powered object. When it is detected that the device connected to the port is a legal powered object device and the device has completed the classification of this powered object, the device starts to supply power to this powered object, outputting a voltage of - 48V. The power supply system of the device is: an IEEE802.3at standard power supply system.

[0012] Step 4: Disconnection stage: Finally, the device detects whether the powered object is disconnected. The device will use a specific detection method to determine whether the powered object has been disconnected. If the powered object is disconnected, the device will turn off the port output voltage, and the port status will return to the detection stage.

[0013] Preferably, in step 1, the output voltage in the detection stage is 2.8V - 10V, and the voltage polarity is the same as the - 48V output. The characteristics of the existence of the powered object are: the DC impedance is between 19K - 26.5Kohm, and the capacitance value does not exceed 150nF.

[0014] Preferably, in step 1, to prevent electrical interference, there are surge protection and reverse power connection protection circuits at the power input end. In addition, electrostatic protection circuits are embedded in the Ethernet port, RS232 / RS485 interface, and SIM card interface to ensure that the device can withstand electrostatic discharges of up to 15kV.

[0015] Preferably, in step 2, the output voltage of the port in the classification stage is 15.5V - 20.5V, and the voltage polarity is the same as the - 48V output.

[0016] Preferably, in step 3, when the device powers the powered object, real-time monitoring and power management are performed. Since it uses a high-definition camera with a relatively high transmission rate, a 4G communication module of CAT4 with full Netcom or a redcap communication module of 5G full Netcom is used as the basic communication transmission unit. A high-performance processor, such as ATMEL AT91SAM9260, is used to ensure stable operation and low power consumption. At the same time, signal strength is crucial for uninterrupted data transmission. Therefore, an external waterproof high-gain antenna is used to significantly enhance the signal reception ability and real-time monitor the mobile network status.

[0017] Preferably, in step 3, the main power supply characteristic parameters of the IEEE802.3at standard power supply system are: the DC voltage is between 50 and 57V, and the typical value is 50V. The typical working current is 10 to 600mA, and the typical output power is 30W. The powered device PD supports Class4 classification. The device output voltage is set at 50 to 57V. Its maximum impedance cannot exceed 12.5Ω. Under these voltage and resistance conditions, the power is equal to: the minimum value of PSE power = 0.72A × 50V = 36W, the minimum value of PD power = 0.72A × 41V = 29.5W, and the maximum cable loss = I2R = 0.72 × 0.72 × 12.5 = 6.5W.

[0018] Preferably, in step 4, when connecting any network device to the device, the device must first detect whether the device is a powered object to ensure that power is not provided to Ethernet devices that do not meet the POE standard. By applying a small current-limited voltage to the cable, it checks whether the remote end has a compliant characteristic resistance. Only when this resistance is detected will the full 48V voltage be provided, but the current is still limited to prevent the terminal device from being in an incorrect state.

[0019] Preferably, in step 4, as an extension of the discovery process, the powered object can also classify the power supply methods required by the device, which helps the device provide power in an efficient manner. Once the device starts providing power, it continuously monitors the current input of the powered object. When the current consumption of the powered object drops below the minimum value, such as when the device is unplugged or when the powered object device has power consumption overload, short circuit, or exceeds the power supply load of the device, the device will disconnect the power supply and restart the detection process.

[0020] Preferably, in step 4, the power supply device can be provided with a system management capability, which enables it to perform night shutdown and remote restart.

[0021] Preferably, in step 4, a watchdog protection mechanism and a timed restart function are set up. The external watchdog circuit SP706 is used together with a software-based watchdog process to continuously monitor critical processes, ensuring that the router remains operational even in the face of potential system failures. At the same time, it is equipped with automatic and timed restart functions, which can be configured through the management interface, helping to regularly reset the system, minimizing downtime, and ensuring consistent connectivity.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] This invention patent boosts DC12V / DC24V to the POE standard DC51V. The boost circuit mainly includes an inductor, switching elements (such as MOSFET or BJT transistors), a freewheeling diode, a filter capacitor, and a load resistor. The switching elements are controlled by PWM signals, quickly switching between conduction and cutoff states to achieve the boost effect. Thus, the DC12V provided by solar energy is boosted to around 51V; at the same time, the communication network provided by the 4G communication module and the 51V power supply are converted through the POE protocol, ultimately forming a new device with a POE standard output powered by solar energy, which is used to solve the problem of POE cameras operating in environments without power and network, effectively reducing the deployment cost of POE cameras in environments such as rivers, reservoirs, and forests. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic circuit diagram of the basic principle of the present invention;

[0025] Figure 2 is a partial circuit of the POE power supply module of the present invention Figure 1 ;

[0026] Figure 3 is a partial circuit of the POE power supply module of the present invention Figure 2 ;

[0027] Figure 4 is a partial circuit of the POE power supply module of the present invention Figure 3 ;

[0028] Figure 5 is a partial circuit of the POE power supply module of the present invention Figure 4 。 DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be described in more detail below by way of examples. These examples are merely illustrative and do not limit the scope of the present invention in any way.

[0030] The present invention provides a technical solution: a method for solving the problem of POE cameras operating in environments without power and network, including the following steps:

[0031] Step 1: Detection stage: First, the device detects whether the powered object exists. The device determines whether the powered object exists by detecting the resistance-capacitance value between the power output line pairs. Only when the powered object is detected will the device perform the next operation;

[0032] Step 2: Classification stage: Then, the device determines the power consumption of the powered object. The device determines the power level of the powered object by detecting the power output current;

[0033] Step 3: Startup stage: After that, the device powers the powered object. When it is detected that the device hanging under the port belongs to a legal powered object device and the device has completed the classification of this powered object, the device starts to power this powered object, outputting a voltage of -48V. The power supply system of the device is: IEEE802.3at standard power supply system;

[0034] Step 4: Disconnection stage: Finally, the device detects whether the powered object is disconnected. The device will use a specific detection method to determine whether the powered object has been disconnected. If the powered object is disconnected, the device will turn off the port output voltage and the port status will return to the detection stage.

[0035] Embodiment 1:

[0036] First, the device detects whether the powered object exists. The device determines whether the powered object exists by detecting the resistance-capacitance value between the power output line pairs. Only when the powered object is detected will the device perform the next operation; then, the device determines the power consumption of the powered object. The device determines the power level of the powered object by detecting the power output current; after that, the device powers the powered object. When it is detected that the device hanging under the port belongs to a legal powered object device and the device has completed the classification of this powered object, the device starts to power this powered object, outputting a voltage of -48V. The power supply system of the device is: IEEE802.3at standard power supply system; finally, the device detects whether the powered object is disconnected. The device will use a specific detection method to determine whether the powered object has been disconnected. If the powered object is disconnected, the device will turn off the port output voltage and the port status will return to the detection stage.

[0037] Embodiment 2:

[0038] In Embodiment 1, add the following processes:

[0039] In step 1, the detection stage output voltage is 2.8V to 10V, and the voltage polarity is the same as the -48V output. Characteristics of the powered object: The DC impedance is between 19K and 26.5Kohm, and the capacitance value does not exceed 150nF; To prevent electrical interference, there are surge protection and reverse power connection protection circuits at the power input. In addition, electrostatic protection circuits are embedded in the Ethernet port, RS232 / RS485 interface, and SIM card interface to ensure that the device can withstand electrostatic discharges of up to 15kV.

[0040] First, the device detects whether the powered object exists. The device determines whether the powered object exists by detecting the resistance and capacitance values between the power output lines. Only when the powered object is detected will the device proceed to the next step; The detection stage output voltage is 2.8V to 10V, and the voltage polarity is the same as the -48V output. Characteristics of the powered object: The DC impedance is between 19K and 26.5Kohm, and the capacitance value does not exceed 150nF; To prevent electrical interference, there are surge protection and reverse power connection protection circuits at the power input. In addition, electrostatic protection circuits are embedded in the Ethernet port, RS232 / RS485 interface, and SIM card interface to ensure that the device can withstand electrostatic discharges of up to 15kV. Then the device determines the power consumption of the powered object. The device determines the power level of the powered object by detecting the power output current; After that, the device powers the powered object. When it is detected that the device connected to the port is a legal powered object device and the device has completed the classification of this powered object, the device starts to power this powered object, outputting a voltage of -48V. The power supply system of the device is: an IEEE802.3at standard power supply system; Finally, the device detects whether the powered object is disconnected. The device will use a specific detection method to determine whether the powered object has been disconnected. If the powered object is disconnected, the device will turn off the port output voltage, and the port status will return to the detection stage.

[0041] Embodiment 3:

[0042] In Embodiment 2, the following processes are added:

[0043] In step 2, the port output voltage in the classification stage is 15.5V to 20.5V, and the voltage polarity is the same as the -48V output.

[0044] In step 3, when the device powers the powered object, it conducts real-time monitoring and power management. Since it uses a high-definition camera with a relatively high transmission rate, it uses a 4G communication module of CAT4 with full Netcom or a redcap communication module of 5G full Netcom as the basic communication transmission unit. It adopts a high-performance processor, such as ATMEL AT91SAM9260, to ensure stable operation and low power consumption. At the same time, signal strength is crucial for uninterrupted data transmission. Therefore, an external waterproof high-gain antenna is used to significantly enhance the signal reception ability and real-time monitor the mobile network status. The main power supply characteristic parameters of the IEEE802.3at standard power supply system are: the DC voltage is between 50 and 57V, and the typical value is 50V. The typical working current is 10 to 600mA, and the typical output power is 30W. The powered device PD supports Class4 classification. The device output voltage is set at 50 to 57V. Its maximum impedance cannot exceed 12.5Ω. Under these voltage and resistance conditions, the power is equal to: Minimum value of PSE power = 0.72A × 50V = 36W Minimum value of PD power = 0.72A × 41V = 29.5W Maximum cable loss = I2R = 0.72 × 0.72 × 12.5 = 6.5W.

[0045] First, the device detects the presence of the powered device. The device determines the presence of the powered device by detecting the resistance-capacitance value between the power output lines. Only when the powered device is detected will the device proceed to the next step. During the detection stage, the output voltage is 2.8V to 10V, and the voltage polarity is the same as the -48V output. Characteristics of the presence of the powered device: The DC impedance is between 19K and 26.5Kohm, and the capacitance value does not exceed 150nF. To prevent electrical interference, there are surge protection and reverse power connection protection circuits at the power input. In addition, electrostatic protection circuits are embedded in the Ethernet port, RS232 / RS485 interface, and SIM card interface to ensure that the device can withstand electrostatic discharges of up to 15kV. Then the device determines the power consumption of the powered device. The device determines the power level of the powered device by detecting the power output current. During the classification stage, the port output voltage is 15.5V to 20.5V, and the voltage polarity is the same as the -48V output. After that, the device supplies power to the powered device. When it is detected that the device connected to the port is a legal powered device and the device has completed the classification of this powered device, the device starts to supply power to this powered device, outputting a voltage of -48V. The power supply system of the device is: an IEEE802.3at standard power supply system. When the device supplies power to the powered device, it conducts real-time monitoring and power management. Because it uses a high-definition camera with a relatively high transmission rate, it uses a CAT4 4G communication module for full-network communication or a 5G full-network redcap communication module as the basic communication transmission unit. It uses a high-performance processor, such as ATMEL AT91SAM9260, to ensure stable operation and low power consumption. At the same time, signal strength is crucial for uninterrupted data transmission. Therefore, an external waterproof high-gain antenna is used to significantly enhance the signal reception ability and monitor the mobile network status in real time. The main power supply characteristic parameters of the IEEE802.3at standard power supply system are: The DC voltage is between 50 and 57V, and the typical value is 50V. The typical operating current is 10 to 600mA, and the typical output power is 30W. The powered device PD supports Class4 classification. The device output voltage is set between 50 and 57V. Its maximum impedance cannot exceed 12.5Ω. Under these voltage and resistance conditions, the power is equal to: Minimum PSE power = 0.72A × 50V = 36W Minimum PD power = 0.72A × 41V = 29.5W Maximum cable loss = I2R = 0.72 × 0.72 × 12.5 = 6.5W. Finally, the device detects whether the powered device is disconnected. The device will use a specific detection method to determine whether the powered device has been disconnected. If the powered device is disconnected, the device will turn off the port output voltage, and the port status will return to the detection stage.

[0046] Example 4:

[0047] In Example 3, the following steps are added:

[0048] In step 4, when connecting any network device to the device, the device must first detect whether the device is a powered device to ensure that power is not supplied to Ethernet devices that do not meet the POE standard. By applying a small current-limited voltage to the cable, it checks whether the remote end has a compliant characteristic resistance. Only when this resistance is detected will the full 48V voltage be supplied, but the current is still limited to prevent the terminal device from being in an incorrect state; as an extension of the discovery process, the powered device can also classify the power supply methods required by the device, which helps the device supply power in an efficient manner. Once the device starts supplying power, it continuously monitors the current input of the powered device. When the current consumption of the powered device drops below the minimum value, such as when the device is unplugged or when there is an overload, short circuit, or power supply load exceeding the device's capacity in the powered device, the device will disconnect the power and restart the detection process; the power supply device can be provided with a system management capability, which enables it to perform night shutdown and remote restart; a watchdog protection mechanism and a timed restart function are set up and used together with an external watchdog circuit SP706 and a software-based watchdog process to continuously monitor critical processes and ensure that the router remains operational even in the face of potential system failures. At the same time, it is equipped with automatic and timed restart functions, which can be configured through the management interface, helping to regularly reset the system, minimize downtime, and ensure consistent connectivity.

[0049] First, the device detects the presence of the powered device. The device determines the presence of the powered device by detecting the resistance-capacitance value between the power output lines. Only when the powered device is detected will the device proceed to the next step. During the detection stage, the output voltage is 2.8V to 10V, and the voltage polarity is the same as the -48V output. Characteristics of the presence of the powered device: The DC impedance is between 19K and 26.5Kohm, and the capacitance value does not exceed 150nF. To prevent electrical interference, there are surge protection and reverse power connection protection circuits at the power input. In addition, electrostatic protection circuits are embedded in the Ethernet port, RS232 / RS485 interface, and SIM card interface to ensure that the device can withstand electrostatic discharges of up to 15kV. Then, the device determines the power consumption of the powered device. The device determines the power level of the powered device by detecting the power output current. During the classification stage, the port output voltage is 15.5V to 20.5V, and the voltage polarity is the same as the -48V output. After that, the device powers the powered device. When it is detected that the device connected to the port is a legal powered device and the device has completed the classification of this powered device, the device starts to power the powered device, outputting a voltage of -48V. The power supply system of the device is: an IEEE802.3at standard power supply system. When the device powers the powered device, it performs real-time monitoring and power management. Because it uses a high-definition camera with a relatively high transmission rate, it uses a CAT4 4G communication module with full network access or a redcap communication module with 5G full network access as the basic communication transmission unit. It uses a high-performance processor, such as ATMEL AT91SAM9260, to ensure stable operation and low power consumption. At the same time, signal strength is crucial for uninterrupted data transmission. Therefore, an external waterproof high-gain antenna is used to significantly enhance the signal reception ability and real-time monitor the mobile network status. The main power supply characteristic parameters of the IEEE802.3at standard power supply system are: the DC voltage is between 50 and 57V, and the typical value is 50V. The typical working current is 10 to 600mA, and the typical output power is 30W. The powered device PD supports Class4 classification. The device output voltage is set between 50 and 57V. Its maximum impedance cannot exceed 12.5Ω. Under these voltage and resistance conditions, the power is equal to: Minimum PSE power = 0.72A × 50V = 36W, Minimum PD power = 0.72A × 41V = 29.5W, Maximum cable loss = I2R = 0.72 × 0.72 × 12.5 = 6.5W. Finally, the device detects whether the powered device is disconnected. The device will use a specific detection method to determine whether the powered device has been disconnected. If the powered device is disconnected, the device will turn off the port output voltage, and the port status will return to the detection stage. When connecting any network device to the device, the device must first detect whether the device is a powered device to ensure that power is not provided to Ethernet devices that do not meet the POE standard. By applying a small current-limited voltage to the cable, it checks whether the remote end has a compliant characteristic resistance.Full 48V voltage is provided only when the resistor is detected, but the current is still limited to prevent the terminal device from being in an incorrect state. As an extension of the discovery process, the powered device can also classify the power supply methods required by the device, which helps the device provide power in an efficient manner. Once the device starts providing power, it continuously monitors the current input of the powered device. When the current consumption of the powered device drops below the minimum value, such as when the device is unplugged or when there is an overload, short circuit, or power supply load exceeding the device's capacity in the powered device, the device disconnects the power supply and restarts the detection process. The power supply device can be provided with a system management capability, which enables it to perform night shutdown and remote restart. A watchdog protection mechanism and a timed restart function are set up and used together with an external watchdog circuit SP706 and a software-based watchdog process to continuously monitor critical processes and ensure that the router remains operational even in the face of potential system failures. At the same time, it is equipped with automatic and timed restart functions, which can be configured through the management interface, helping to regularly reset the system, minimize downtime, and ensure consistent connectivity.

[0050] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for a POE camera to work in an environment without power and network, characterized in that: It includes the following steps: Step 1: Detection stage: First, the device detects whether the powered object exists. The device determines whether the powered object exists by detecting the resistance-capacitance value between the power output lines. Only when the powered object is detected will the device perform the next operation; Step 2: Classification stage: Then the device determines the power consumption of the powered object. The device determines the power level of the powered object by detecting the power output current; Step 3: Startup stage: After that, the device powers the powered object. When it is detected that the device connected to the port is a legal powered object device and the device has completed the classification of this powered object, the device starts to power the powered object, outputting a voltage of -48V. The power supply system of the device is: IEEE802.3at standard power supply system; Step 4: Disconnection stage: Finally, the device detects whether the powered object is disconnected. The device will use a specific detection method to determine whether the powered object has been disconnected. If the powered object is disconnected, the device will turn off the port output voltage and the port status will return to the detection stage.

2. The method for solving the problem of a POE camera working in a power-off and network-off environment according to claim 1, wherein: In Step 1, the output voltage in the detection stage is 2.8V to 10V, and the voltage polarity is the same as the -48V output. The characteristics of the existence of the powered object are: the DC impedance is between 19K and 26.5Kohm, and the capacitance value does not exceed 150nF.

3. The method for solving the problem of a POE camera working in a power-off and network-off environment according to claim 1, wherein: In Step 1, in order to prevent electrical interference, there are surge protection and reverse power connection protection circuits at the power input. In addition, electrostatic protection circuits are embedded in the Ethernet port, RS232 / RS485 interface, and SIM card interface to ensure that the device can withstand electrostatic discharges of up to 15kV.

4. The method for solving the problem of the POE camera working in a power-off and network-off environment according to claim 1, characterized in that: In Step 2, the output voltage of the port in the classification stage is 15.5V to 20.5V, and the voltage polarity is the same as the -48V output.

5. The method for solving the problem of a POE camera working in a power-off and network-off environment according to claim 1, wherein: In Step 3, when the device powers the powered object, it performs real-time monitoring and power management. Because it uses a high-definition camera with a relatively high transmission rate, it uses a CAT4 4G communication module with full network access or a redcap communication module with 5G full network access as the basic communication transmission unit. It uses a high-performance processor, such as ATMEL AT91SAM9260, to ensure stable operation and low power consumption. At the same time, signal strength is crucial for uninterrupted data transmission. Therefore, an external waterproof high-gain antenna is used to significantly enhance the signal reception ability and monitor the mobile network status in real time.

6. The method for solving the problem of the POE camera working in a power-off and network-off environment according to claim 1, wherein: In Step 3, the main power supply characteristic parameters of the IEEE802.3at standard power supply system are: the DC voltage is between 50 and 57V, and the typical value is 50V. The typical working current is 10 to 600mA, and the typical output power is 30W. The powered device PD supports Class4 classification. The device output voltage is set between 50 and 57V. Its maximum impedance cannot exceed 12.5Ω. Under this voltage and resistance condition, the power is equal to: Minimum PSE power = 0.72A × 50V = 36W Minimum PD power = 0.72A × 41V = 29.5W Maximum cable loss = I2R = 0.72 × 0.72 × 12.5 = 6.5W.

7. The method for solving the problem of a POE camera working in a power-off and network-off environment according to claim 1, wherein: In step 4, when connecting any network device to the device, the device must first detect whether the device is a powered device to ensure that power is not supplied to Ethernet devices that do not meet the POE standard. By applying a small current-limited voltage to the cable, it checks whether the remote end has a compliant characteristic resistance. Only when this resistance is detected will the full 48V voltage be supplied, but the current is still limited to prevent the terminal device from being in an incorrect state.

8. The method for solving the problem of a POE camera working in a power-off and network-off environment according to claim 1, characterized in that: In step 4, as an extension of the discovery process, the powered device can also classify the power supply methods required by the device, which helps the device supply power in an efficient manner. Once the device starts supplying power, it continuously monitors the current input of the powered device. When the current consumption of the powered device drops below the minimum value, such as when the device is unplugged or when there is an overload, short circuit, or power supply load exceeding the device's capacity in the powered device, the device will disconnect the power supply and restart the detection process.

9. The method for solving the problem of a POE camera working in a power-off and network-off environment according to claim 1, characterized in that: In step 4, the power supply device can be provided with a system management capability, which enables it to perform night shutdown and remote restart.

10. The method for solving the problem of a POE camera working in a power-off and network-off environment according to claim 1, wherein: In step 4, a watchdog protection mechanism and a timed restart function are set up. By using the external watchdog circuit SP706 together with a software-based watchdog process, it continuously monitors critical processes to ensure that the router remains operational even in the face of potential system failures. At the same time, it is equipped with automatic and timed restart functions, which can be configured through the management interface, helping to periodically reset the system, minimize downtime, and ensure consistent connectivity.

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