However, the transmission is less than 800 meters. At a distance of 800 meters, the pressure drop is very serious. POE power supply voltage is 48V, which cannot support 800 meters at all.
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A complete POE system includes PSE, power supply equipment (PSE) and power supply equipment (PD). PSE equipment is the equipment that supplies power to Ethernet client equipment, and it is also the manager of the whole POE Ethernet power supply process. PD equipment is the PSE load that receives power, that is, the client equipment of POE system, such as IP phone, network security camera, AP, PDA or mobile phone charger and other Ethernet devices (in fact, any equipment with power less than 13W can get corresponding power from RJ45 socket). Based on IEEE 802.3af standard, they establish information connection about the connection, device type and power consumption level of the receiving device PD, and supply power to the PD through Ethernet according to PSE.
The main power supply characteristic parameters of POE standard power supply system are:
The voltage of 1. is between 44 and 57V, with a typical value of 48V.
2. The maximum allowable current is 550mA, and the maximum starting current is 500mA.
3. The typical working current is 10 ~ 350 Ma, and the overload detection current is 350 ~ 500 Ma.
4. Under no-load condition, the maximum required current is 5mA.
5. Provide PD equipment with five levels of power demand of 3.84 ~ 12.95 W, with a maximum of13w. ..
2. The working process of 2.Poe power supply
When PSE power supply terminal equipment is networked, the working flow of POE Ethernet power supply is as follows.
1. detection: First, the PSE device outputs a small voltage at the port until it detects that the cable terminal is connected to the power receiving device supporting the IEEE 802.3af standard.
2. Classification of partial discharge terminal equipment: When partial discharge is detected, PSE equipment can classify partial discharge equipment and evaluate the power consumption required by the partial discharge equipment.
3. Start power supply: within a configurable time (generally less than 15μs), PSE equipment starts to supply power to PD equipment from low voltage until 48V DC power supply is provided.
4. Power supply: provide stable and reliable 48V direct current for PD equipment, so that the power consumption of PD equipment shall not exceed15.4W..
5. Power failure: If the PD equipment is disconnected from the network, PSE will quickly stop supplying power to the PD equipment (generally within 300 ~ 400 ms), and repeat the detection process to check whether the terminal of the cable is connected to the PD equipment.