We often hear that PoE power supply distance is only 100 meters. Why is the transmission distance limited to 100 meters?

Since most PoE switches nowadays have been upgraded to 100Mbps, 1Gbps, or even 10Gbps switches, their Ethernet ports have speeds of 100Mbps or higher.

Data delays and packet loss may occur when the maximum transmission distance exceeds 100 meters. Therefore, most specifications will state that the transmission distance should not exceed 100 meters.

So how do we extend the PoE power supply distance? In this case, we need to force the Ethernet port to 10M. When the Ethernet port is working in 10M mode, the transmission distance is extended to 250 meters. Therefore, if the bandwidth requirement is lower than 10M, but the transmission distance must be greater than 100 meters, the 10M mode can be considered.