LTPoE++ is Linear Technology’s power over Ethernet classification scheme that uses proprietary signaling methods to classify and provide LTPoE++ powered devices with up to 90W of power. LTPoE++ is interoperable and backward compatible with both IEEE 802.3af and 802.3at PoE standards, so LTPoE++, PoE+ and PoE devices can all be mixed and matched. LTPoE++ uses a single Ethernet cable to transfer power from the power sourcing equipment (from now on it will be referred to as the PSE) to the powered device (or PD). Four discrete LTPoE++ power levels are available, so that external components in the power path, such as transformers and DC/DC converters can be sized accordingly and designs can be optimized both in terms of cost and efficiency. The table on this slide shows a comparison between LTPoE++ and IEEE standards. The third column shows how much power is available at the PD input based on the chosen standard. As can be seen, LTPoE++ adds four power levels to this list: 38.7W, 52.7W, 70W and 90W.