PoE is a technology that allows sending electrical power simultaneously with Ethernet data along the same Ethernet copper cable. In terms of PoE devices there are two main categories, Power Sourcing Equipment (PSE) and Powered Device (PD). PSE is usually a PoE capable Ethernet switch and a PD is a PoE compatible end device, such as an IP camera or an IP phone. Currently, there are 2 main Power over Ethernet categories standardized by IEEE. IEEE 802.3af is a Power over Ethernet standard that specifies the maximum power output of 15.4 W. The second standard, IEEE 802.3at, specifies the maximum power output of 34.2 W, this standard is also called Power over Ethernet Plus (PoE+). Power over Ethernet devices are also divided into midspan and endspan device categories. Midspan PoE equipment is a device that is placed between an Ethernet switch and an end device. Midspan PoE device receives Ethernet data from a switch and forwards this data with power to an end device. The PoE Endspan device is usually a PoE capable switch that forwards Ethernet data together with power directly to an end device. In terms of Ethernet cable pinout used for power, midspan uses pins 4,5,7 and 8, Endspan uses pins 1,2,3 and 6 to deliver electrical power to an end device. Power over Ethernet technology also negotiates the required voltage and pins to deliver electrical power, this feature is called active PoE. Passive PoE is when there is no negotiation. Passive PoE makes use of Ethernet cable pins described in IEEE standard while the voltage is set by an Ethernet switch.