Often the installation of a power outlet or source near the remote device is costly and prohibitive. PoE provides the answer by delivering power via the same Ethernet cable that connects the data to the remote device. The specification for PoE has been defined by the IEEE and sets various levels and classes of power. The initial standard know as IEEE802.3af allowed a maximum of 12.95W to be delivered to the remote device. Four classes (0-3) were defined to allow the inteligent detection and allocation of power by the source according to a signature presented by the remote device. This feature helps distribute available power in a multiport switch. IEEE802.3at added a class 4 which increases the available remote power to 25.5W. Recently the new IEEE802.3bt standard pushes this to as much as 100W!

Practical limitations such as cable length (100m), cable gauge and heat dissipation in cable bundles need to be taken into consideration when deploying PoE.

Incorporating PoE in your product is not trivial but Innovelec and its partner Infomart have many man years experience in these designs. We will gladly offer our assistance at both the schematic and layout phase. Close attention to isolation (as required by the IEEE802.3 standard), grounding topology and EMI/EMC considerations are important. We strongly recommend making provision for a Kintec KTA1550/KTA1552 EMI Reduction / ESD Protection device in your design.