PoE-BT Power
General PoE background
Microsemi PDS-408G Web Management User Guide Ver. 1.0.1, 03-2019
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7
POE-BT POWER
7.1
General PoE background
PoE-BT (IEEE 802.3-bt) is the latest PoE (Power Over Ethernet) specification offering up to 90[W] of
power whenever power is delivered over all four RJ45 cable pairs. PoE-BT is backwards compatible
with PoE-AT (IEE 802.3at) offering up to 30W over two out of four cable pairs of the RJ45 connector.
PoE-BT is also backwards compatible with the first PoE specification known as PoE-AF (IEEE 802.3af)
capable of delivering up to 15W on two out of four cable pairs inside the RJ45 connector.
The maximum power offered for each PD (Powered device) as Access Point, IP-Cameras, etc. is
determined by each PD classification named Class. The Switch detects the PoE class advertised by
every PD and allocates Maximum-Power for each port accordingly.
Poe-PD
Class
Maximum allocated
Power [W] by the
Switch
PoE-BT
support
PoE-AT
Support
PoE-AF
Support
0
15.4 (same as class-3)
Yes
Yes
Yes
1
4
Yes
Yes
Yes
2
7
Yes
Yes
Yes
3
15.4
Yes
Yes
Yes
4
30
Yes
Yes
---
5
45
Yes
---
---
6
60
Yes
---
---
7
75
Yes
---
---
8
90
Yes
---
---
Table 7-1: PoE maximum power[W] per PD advertised class