What virtual currency is Poe
Poe is also known as power over LAN (POL) or active Ethernet (active Ethernet), sometimes referred to as Ethernet power supply, which is the latest standard specification of using existing standard Ethernet transmission cable to transmit data and power at the same time, and maintains compatibility with existing Ethernet systems and users. IEEE 802.3af standard is a new standard based on POE of power supply system over Ethernet. It adds the relevant standard of direct power supply through network cable on the basis of IEEE 802.3. It is an extension of the existing Ethernet standard and the first international standard on power distribution
IEEE began to develop this standard in 1999. The earliest participating manufacturers were 3Com, Intel, powerdsine, Nortel, mitel and national semiconctor. However, the shortcomings of the standard have been restricting the expansion of the market. Until June 2003, IEEE approved 802.3af standard, which clearly stipulated the power detection and control matters in remote system, and regulated the power supply mode of router, switch and hub to IP phone, security system and wireless LAN access point through Ethernet cable. The development of IEEE 802.3af includes the efforts of many company experts, which also makes the standard can be tested in all aspects< br />
POE (power over Ethernet) refers to the operation of some IP based terminals (such as IP telephone, WLAN access point AP, network camera, etc.) without any changes to the existing Ethernet cat. 5 cabling infrastructure
Poe is also known as LAN based power supply system or active Ethernet, sometimes referred to as Ethernet power supplythis is the latest standard specification that uses the existing standard Ethernet transmission cable to transmit data and electric power at the same time, and maintains the compatibility with the existing Ethernet system and users
Poe system composition: a complete Poe system includes two parts: the power supply end equipment and the power receiving end equipment. The PSE equipment is the power supply equipment for the Ethernet client equipment. At the same time, it is also the manager of the whole Poe Ethernet power supply process
The PD device is the client device of Poe system, such as IP phone, network security camera, AP, PDA or mobile phone chargerbased on IEEE 802.3af standard, the two establish information contact about PD connection, device type, power consumption level and so on, and supply power to PD through Ethernet according to PSE
Poe is also known as power over LAN (POL) or active Ethernet (active Ethernet), sometimes referred to as Ethernet power supply, which is the latest standard specification of using existing standard Ethernet transmission cable to transmit data and power at the same time, and maintains the compatibility with existing Ethernet system and users. IEEE 802.3af standard is a new standard based on POE of power supply system over Ethernet. It adds the relevant standard of direct power supply through network cable on the basis of IEEE 802.3. It is an extension of the existing Ethernet standard and the first international standard on power distribution.
3902900090 other primary shape olefin polymer
export tax rebate: 5.0%
import tariff MFN: 6.5%
import tariff common: 45.0%
export tariff rate: 0.0%
import value-added tax: 17.0%
consumption tax: 0.0%
declaration elements: 1. Proct name; 2. Appearance; 3. The content of the components was determined; 4. The type and proportion of monomer units; 5. Grade; 6. Brand 7, model
Poe procts use
3926909090 other plastic procts (including procts of materials listed in items 3901 to 3914)
export tax rebate: 13.0%
import tariff MFN: 10.0%
import tariff general: 80.0%
export tariff rate: 0.0%
import value-added tax: 17.0%
consumption tax: 0.0%
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as the advantages of Poe switch are graally understood by everyone, the application of Poe switch in network monitoring system is more and more common. It is inevitable that there will be a mix of good and bad procts in the market, and some Poe switches that do not meet the POE power supply standard begin to appear
2. Classification of Poe switches
standard Poe switches, which comply with IEEE802.3af and 802.3at standards, are standard Poe switches (commonly known as 48V). The complete Poe includes two parts: power souring equipment (PSE) and power device (PD). Poe switch is a kind of PSE equipment. PSE is a device that supplies power to the terminal, and it is also the manager of Poe Ethernet power supply process. PD is the terminal equipment receiving power supply (48V national standard equipment contains PD chip)
on the contrary, it is a non-standard Poe switch ("non-standard" is referred to as "non-standard" for short, commonly known as 24 V, but not marked with 48 V, 24 V, 12 V, 5 V, etc.)< The main application fields of Poe switch are as follows:
Poe switch mainly provides network and power supply for monitoring (power supply for camera), wireless coverage (power supply for AP) and wireless transmission (power supply for bridge)< 4. Working process of the standard Poe power supply switch
1. Detection: the POE switch first outputs a very small voltage, and detects the receiving end equipment (PD) supporting ieee802.3at/af standard chip)
2. PD classification: after PD is detected, Poe switches classify PD devices and evaluate the power of PD devices
3. Power supply: ring the start-up period (generally less than 15 days) μ s) Poe switches supply power to PD from low voltage until enough voltage is supplied for PD to provide stable and reliable DC power for PD equipment
4. Power off: if the PD device is disconnected, the POE switch will stop power supply to the PD quickly (generally within 300-400ms), and repeat the detection process to detect whether the cable terminal is connected to the PD device< br />
< 5. Test method for true and false Poe with universal meter
start the equipment, adjust the multimeter to the voltage measuring gear, and touch the power supply pin of PSE equipment (usually 1 / 2, 3 / 6 or 4 / 5, 7 / 8 of RJ45 port) with two probes of the multimeter respectively. If the device has stable output of 48V or other voltage values (12V, 24V, etc.), it is a non-standard proct. Because in this process, PSE does not detect the receiving equipment (here is the multimeter), and directly uses 48V or other voltage values for power supply