Which PoE standard provides the highest power per port among common standards?

Which PoE standard provides the highest power per port among common standards?

• A. 802.3bt (PoE++)
• B. 802.3af (PoE)
• C. 802.3at (PoE+)
• D. All provide the same power

Answer: (A)

In PoE, how much power per port you can deliver is set by the standard, and newer revisions boost that amount by using all four pairs and higher current. The earliest PoE standard allows about 15.4 W to the device (PD). PoE+ increased that to roughly 25.5 W. The PoE++ family introduces Type 3 and Type 4, with Type 3 delivering up to about 60 W per port and Type 4 up to about 90 W per port, when the network hardware and cable support it. Because of these higher capabilities, PoE++ provides the highest power per port among the common standards. In real deployments, the actual power depends on cable quality and length (which affects voltage drop) and on the specific PSE/PD negotiation and capabilities.

In PoE, how much power per port you can deliver is set by the standard, and newer revisions boost that amount by using all four pairs and higher current. The earliest PoE standard allows about 15.4 W to the device (PD). PoE+ increased that to roughly 25.5 W. The PoE++ family introduces Type 3 and Type 4, with Type 3 delivering up to about 60 W per port and Type 4 up to about 90 W per port, when the network hardware and cable support it. Because of these higher capabilities, PoE++ provides the highest power per port among the common standards. In real deployments, the actual power depends on cable quality and length (which affects voltage drop) and on the specific PSE/PD negotiation and capabilities.