Networking / AV-IT
PoE — Power over Ethernet
01 — Definition
The IEEE standard that carries DC power down the Ethernet cable alongside the data. Per port: 15.4 W on 802.3af (PoE), 30 W on 802.3at (PoE+), 60 W on 802.3bt Type 3 (PoE++), 90 W on Type 4. Watch the switch's PoE budget — the total power shared across all ports: a 24-port PoE+ switch may cap at 370 W in total, not 30 W per port simultaneously.
02 — In the field
Look at the switch's total PoE budget, not just the per-port maximum. A switch rated 30 W per port but with a 370 W overall budget cannot power 24 devices at 30 W at the same time. Add up your devices' real draw and compare it against the total budget.
04 — Sources
- Handbook for Sound Engineers, Ballou, 4e éd. 2008, §14.9.3.6.9 — 802.3af : 15,4 W au PSE, 12,95 W au PD