The lights on POE switches mainly include power indicator lights, system operation status lights, POE mode status lights, and business interface indicator lights. Their meanings are as follows:
Power indicator light (PWR):
Green constantly on: indicates that the power supply of the switch is normal and the device has been successfully powered on.
Extinguish: This indicates that the device is not powered on, possibly due to the power cord not being connected properly or a power failure. It is necessary to check if the external power supply is connected correctly and if there is any current input.
Yellow (may appear in some devices): If it is a switch with a built-in power supply, a bright yellow color indicates an internal power failure in the switch, and the switch is currently using an external backup power supply (RPS) for power supply; If the switch is configured with dual power modules, a bright yellow color (which may appear red in some older devices) indicates that the corresponding power module is abnormal.
System Operation Status Light (SYS):
Green flashing: indicates that the system is in the process of starting up.
Green constantly on: The system has completed startup and is running normally.
Red constantly on: The switch may have issues such as fan failure, abnormal temperature alarm, or other system failures. If a fan module is used, it is necessary to first check whether the indicator light on the fan module is normal (usually green slow flashing), and then check whether the working environment of the switch is abnormal, causing the switch to operate at a high temperature.
POE mode status light:
Constant off: indicates that POE mode has not been selected.
Green constantly on: ｓｅｌｅｃｔ POE mode, and the business interface indicator light is indicating the POE status of the interface.
Business interface indicator light: Depending on the device, the display method and meaning of the business interface indicator light may vary. Generally speaking:
Default mode (STAT mode):
Constant shutdown: The interface is disconnected or closed.
Green constantly on: The interface is connected.
Green flashing: The interface is sending or receiving data.
POE mode:
Green constantly on: This interface is remotely powered, providing POE power to connected devices.
Green flashing: The power of the recipient exceeds the interface power supply capacity or the set threshold, or the recipient's device is a non IEEE standard PD device.
Power related fault diagnosis
The power indicator light (PWR) is not on:
This is the most obvious signal of a power issue. Firstly, check if the power cord is securely plugged into the power interface and socket of the switch. If the power cord is connected properly, it may be a problem with the power adapter. You can try replacing it with a power adapter of the same specifications to determine if it is a problem with the power supply itself.
For switches with built-in power supply, it is also possible that the internal power module is damaged. In this case, professional personnel are required for maintenance or technical support from equipment suppliers needs to be contacted.
Power indicator light (PWR) yellow (some devices) flashing or constantly on (not green):
As mentioned earlier, for switches with dual power module configurations, this may indicate that one of the power modules has malfunctioned. You can check the power module status indicator light of the device (if any) to further determine which module is abnormal.
For switches that use internal power supply and external backup power supply (RPS), a yellow light may indicate that the internal power supply has malfunctioned and the backup power supply is being used. At this point, it is necessary to check the cause of the internal power supply malfunction, such as power circuit failure, over temperature protection triggering, etc.
System operation fault diagnosis
The system running status light (SYS) is always red and on:
This indicates a serious malfunction in the switch system. It may be due to hardware malfunctions, such as chip overheating, memory failure, etc. Check the heat dissipation of the switch to see if there is any fan stalling or blocked ventilation opening causing the device to overheat. If the heat dissipation is normal, it may be due to damage to internal hardware components, and further inspection by professional equipment maintenance personnel is required.
It could also be a software malfunction, such as a system crash or configuration error. You can try connecting to the device through the console port of the switch (if available), check the system logs to determine the cause of the failure, or try restarting the switch to see if the failure can be restored.
POE function fault diagnosis
POE mode status light is not on (when it should be on):
Firstly, check if the switch is correctly configured for POE mode. If configured correctly, it may be a malfunction in the POE module. In this case, POE devices connected to the switch port will not be able to receive power supply.
Abnormal business interface indicator light (POE mode):
Green flashing (POE mode): If the interface indicator light flashes green in POE mode, it may be due to the power of the receiving party exceeding the interface's power supply capacity or the set threshold, or the receiving party's device being a non IEEE standard PD (power receiving device) device. It is necessary to check whether the power requirements of the connected devices are within the power supply capacity range of the switch ports, and whether the devices comply with POE standards.
Constant off (when it should be on in POE mode): indicates that this interface is not remotely powered. It may be a fault in the POE power supply line, such as a damaged Ethernet cable or a connected device that does not support POE functionality. You can try replacing the Ethernet cable or connecting a known POE supported device to further determine the cause of the malfunction.
Port connection and data transmission fault diagnosis
The business interface indicator light (in STAT mode) is constantly off:
In the default STAT mode, the interface indicator light being constantly off indicates that the interface is not connected or has been turned off. Firstly, check if the Ethernet cable is correctly inserted into the switch port and terminal device port. If the network cable connection is normal, it may be due to the interface being manually turned off (in the switch configuration). You need to log in to the switch configuration interface to check the port status and re enable the port.
The business interface indicator light (in STAT mode) is always green, but the device cannot communicate:
This situation indicates that the interface is connected, but there may be issues with data transmission. Possible network configuration errors, such as VLAN configuration errors, IP address conflicts, etc. Check the network configuration of the connected devices and switches to ensure they are in the same network segment and VLAN settings are correct. It is also possible that the network cable is stored in a damaged core, and although the physical connection is normal, data cannot be transmitted properly. A network cable tester can be used to check the quality of the network cable.