Which PoE standard can deliver up to 90 W per port?

Which PoE standard can deliver up to 90 W per port?

• A. 802.3af (PoE)
• B. 802.3at (PoE+)
• C. 802.3bt (PoE++) up to 60 W
• D. 802.3bt (PoE++) up to 90 W

Answer: (D)

Power delivery in PoE scales with the standards. Early PoE can feed only modest power by sending it over two pairs, which limits the per-port wattage to roughly 15 W for PoE and about 25–30 W for PoE+. To reach 90 W per port you need the newer PoE++ specification, which is 802.3bt in Type 4. This update uses all four pairs to carry power and increases the voltage/current budget, allowing up to 90 W to the powered device per port. For this to work, the power sourcing equipment and the powered device both must support Type 4 PoE++, and the cable must be able to handle the higher power with acceptable losses. In practice, the exact wattage seen at the device can vary with cable length and category, but 90 W per port is the defined maximum for this standard.

Power delivery in PoE scales with the standards. Early PoE can feed only modest power by sending it over two pairs, which limits the per-port wattage to roughly 15 W for PoE and about 25–30 W for PoE+. To reach 90 W per port you need the newer PoE++ specification, which is 802.3bt in Type 4. This update uses all four pairs to carry power and increases the voltage/current budget, allowing up to 90 W to the powered device per port.

For this to work, the power sourcing equipment and the powered device both must support Type 4 PoE++, and the cable must be able to handle the higher power with acceptable losses. In practice, the exact wattage seen at the device can vary with cable length and category, but 90 W per port is the defined maximum for this standard.