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Power over Ethernet (PoE) is the term for the standard IEEE 802.3af, which enables end appliances that have less then 12.95 Watt power consumption to also be supplied with electricity directly through the Ethernet cable.
In the strictly speaking sense, PoE today usually refers to the IEEE standard 802.3 Clause 33 "DTE Power over MDI", which was first introduced in June 2003 as IEEE 802.3af-2003. There is also a newer standard IEEE 802.3at-2009 - also known as PoE+ or PoE plus before standardization - which increases the maximum power output from 15.4 W to 25.5 W. This new standard is called IEEE 802.3at-2009. Previously, there were already several manufacturer-specific implementations that were also traded under the name Power over Ethernet. In addition, there are still proprietary variants.
The standard divides the devices involved into
The supply voltage is 48 V, the maximum current consumption of the terminal devices is 350 mA (802.3af, type 1) or 600 mA (802.3at, type 2) in continuous operation (400 mA are permitted for a short time when switched on)
IEEE-Standard | PoE (802.3af-2003) | PoE Plus (802.3at-2009) | 4-paar PoE (802.3bt-2018) |
---|---|---|---|
Output voltage in V (DC) | 36–57 | 42,5–57 | 42,5–57 |
Output current Operation in mA (DC) | 350 | 600 | 2× 960 |
Output current Start mode in mA (DC) | 400 | 400 | ? |
Power of the (PSE) supply in W | max. 15,4 | max. 30 | 45; 60; 75; 90 |
Power at end device (PD) in W | max. 12,95 | max. 25,5 | 40; 51; 62; 71 |
PSE-Class | 1; 2; 3 | 4 | 5; 6; 7; 8 |
supported devices (PD-Type) | 1 | 1 und 2 | 1; 2; 3; 4 |
Used wire pairs | 2 | 2 | 2 und 4 |
Class | Available power on the supplied device | classification signature |
---|---|---|
0 | 0,44–12,96 W | 0 to 4 mA |
1 | 0,44–3,84 W | 9 to 12 mA |
2 | 3,84–6,49 W | 17 to 20 mA |
3 | 6,49–12,95 W | 26 to 30 mA |
4 | 12,95–25,50 W (only 802.3at/Typ 2) | 36 to 44 mA |
Source: https://de.wikipedia.org/wiki/Power_over_Ethernet
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