POE标准为使用以太网的传输电缆输送直流电到POE兼容的设备定义了两种方法：一种称作“中间跨接法”( Mid -Span )，使用以太网电缆中没有被使用的空闲线对来传输直流电，相应的Endpoint PSE支持POE功能的以太网交换机、路由器、集线器或其他网络交换设备。另一种方法是“末端跨接法”(End-Span)，是在传输数据所用的芯线上同时传输直流电，其输电采用与以太网数据信号不同的频率。Midspan PSE是一个专门的电源管理设备，通常和交换机放在一起。它对应每个端口有两个RJ45插孔，一个用短线连接至交换机，另一个连接远端设备。可以预见，End-Span会迅速得到推广，这是由于以太网数据与输电采用公用线对，因而省去了需要设置独立输电的专用线，这对于仅有8芯的电缆和相配套的标准RJ-45插座意义特别重大。
Poe standard defines two methods for using Ethernet transmission cable to transmit DC power to Poe compatible devices: one is called "mid span", which uses idle pairs of unused Ethernet cables to transmit DC power, and the corresponding endpoint PSE supports Ethernet switches, routers, hubs or other network switching devices with POE function. The other method is "end span", which transmits DC power at the same time on the core wire used for data transmission, and its transmission frequency is different from that of Ethernet data signal. The midspan PSE is a dedicated power management device that is usually placed with a switch. It has two RJ45 sockets corresponding to each port, one of which is connected to the switch with a short wire, and the other is connected to the remote device. It can be foreseen that end span will be popularized rapidly. This is because Ethernet data and power transmission adopt public line pairs, thus eliminating the need to set up a dedicated line for independent power transmission, which is of great significance for only 8-core cables and standard RJ-45 sockets.
下图是POE供电系统的一个实例，由供电设备PSE 、受电设备PD和相关的配套设备及以太网传输电缆组成。
The figure below is an example of Poe power supply system, which is composed of power supply equipment PSE, power receiving equipment PD, relevant supporting equipment and Ethernet transmission cable.