What is the working process of a POE switch?

POE (Power Over Ethernet) refers to some IP-based terminals (such as IP phones, wireless LAN access points APs, network cameras) without any changes to the existing Ethernet Cat.5 cabling infrastructure. Etc.) While transmitting data signals, it can also provide direct current technology for such devices. It is a switch that supports Power over Ethernet.

When deploying a POE switch in a network, the POE switch works as follows:

Detection: At the beginning, the poe switch outputs a very small voltage at the port until it detects that the cable terminal is connected to a power-receiving device that supports the IEEE 802.3af standard.

PD end device classification: After detecting the PD of the power end device, the POE switch may classify the PD device and evaluate the power loss required by the PD device.

Start of power supply: During a startup period of a configurable time (typically less than 15μs), the poe switch starts to supply power from the low voltage to the PD device until a 48V DC power supply is provided.

Power supply: Provides a stable and reliable 48V DC power for the PD equipment, to meet the PD equipment does not exceed the 15.4W power consumption.

Power-off: If the PD device is disconnected from the network, the poe switch will quickly stop supplying power to the PD device (usually within 300 to 400 ms) and repeat the detection process to check whether the cable's terminal is connected to the PD device.

A complete POE system includes PSE (Power Sourcing Equipment) and PD (Power Device), and poe switch is a PSE device. The PSE device is a device that provides power for Ethernet client devices and is also the administrator of the entire PoE Power over Ethernet process. The PD device is a PSE load that receives power, that is, a client of a POE system.