PoE Standards Guide: PoE vs PoE+ vs PoE++ (802.3af/at/bt) Power, Applications and Selection

30/04/2026 Langzhi Technology


Complete PoE standards guide covering IEEE 802.3af (PoE), 802.3at (PoE+) and 802.3bt (PoE++ Type 3/4). Power specs, compatible devices, budget calculation and switch selection.

PoE Standards Overview

PoE (802.3af): 15.4W max, 12.95W available. For IP phones, fixed APs, basic cameras. 2-pair power delivery.

PoE+ (802.3at): 30W max, 25.5W available. For dual-band APs, PTZ cameras. 2-pair, backward compatible.

PoE++ Type 3 (802.3bt): 60W max, 51W available. For small cells, conference systems. 4-pair delivery.

PoE++ Type 4 (802.3bt): 90-100W max, 71.3W available. For LED lighting, displays, laptops. 4-pair.

All standards support 100m max distance over CAT5+ cable. Our PoE switches support all standards.

For long-distance PoE, use SFP modules for fiber uplink from PoE switches.

Power Budget Calculation

Total PoE budget must support all connected devices. A 24-port PoE+ switch with 370W budget can power ~14 PoE+ cameras at full load.

Conclusion

Visit Langzhi Technology for PoE switches from 4 to 48 ports.



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