If I connect a device configured for LTPoE++ (e.g., using an LT4293) to an IEEE 802.3bt-compliant PSE, what will the result be?

When an LTPoE++ PD is connected to an 802.3bt PSE, the devices will negotiate down to the highest common standard they both support. The PD will not operate at the full 90W LTPoE++ power level. Instead, the PD will recognize the 802.3bt PSE and function as a Class 8 (Type 4) device, limiting its power draw to a maximum of 71.3W. This is a critical feature of modern PoE controllers, which ensures compatibility and prevents damage by adhering to the rules of the discovered PSE standard.

If I connect a device configured for LTPoE++ (e.g., using an LT4293) to an IEEE 802.3bt-compliant PSE, what will the result be?

When an LTPoE++ PD is connected to an 802.3bt PSE, the devices will negotiate down to the highest common standard they both support. The PD will not operate at the full 90W LTPoE++ power level. Instead, the PD will recognize the 802.3bt PSE and function as a Class 8 (Type 4) device, limiting its power draw to a maximum of 71.3W. This is a critical feature of modern PoE controllers, which ensures compatibility and prevents damage by adhering to the rules of the discovered PSE standard.