PoEsmart is an inline tester designed to support IEEE 802.3bt Power-over-Ethernet standard. It detects the existence and identifies both standard (active) and non-standard (passive) PoE systems. When connected to a passive PD, PoEsmart displays the voltage and polarity of the operating PoE data pair and spare pair. For active PoE systems, PoEsmart is designed with an internal power device simulator known as SPD (simulate power device) to perform a negotiation process with the PSE (power source equipment) to establish voltage, current, and power draw of IEEE 802.3af / 802.3at / UPoE / 802.3bt Type 3 (4PPoE) and 802.3bt Type 4 PoE standards. When linked with a PD and PSE, PoEsmart will actively analyze and monitor the voltage, current, polarity, and wattage supplied by PSE to PD without interrupting data flow. Results are shown on an OLED high-resolution display for an enhanced viewing quality and wider viewing angle suitable for various settings. With its extensive display, PoEsmart delivers a balanced layout for full visibility of the data to eliminate the inconvenience of scrolling or rotating for contents. PoEsmart is the next generation of Power Over Ethernet Tester that is crucial when managing PoE systems.