Power over Ethernet or POE is a system in technology that is mainly used for IP cameras but now becoming more ubiquitous with the advent of Industry 4.0 and the Internet of Things. POE allows for both power and Ethernet to pass through on a single cable, eliminating the need for two cables on a device. The ability to use a single cable to pass both power and data stems from a phantom power technique that provides greater flexibility for data transmission speeds from: 10BASE-T; 100BASE-T; 1000BASE-T (gigabit Ethernet); 2.5GBASE-T; 5GBASE-T; and  10GBASE-T.

In order to create a network of POE, power is passed through cabling from a power sourcing equipment (PSE) to a powered device (PD). There are three modes for this—Mode A, Mode B, and 4-Pair. Mode A is similar to the technique of phantom feeding where both power and data are carried on the same wire whereas. Mode B uses the alternative wires to carry power. 4-Pair also is a new standard that uses all 4 wire pairs to carry power and data.  

In the last few years, the Institute of Electrical and Electronics Engineers Standards Association is slowly introducing and testing a new mode called 4 pair transmission or 4PPOE, which provides power using all four pairs of a twisted-pair cable. By increasing the amount of power transferred, it opens the door to new applications as more devices and sensors are being connected in the growing world of IT and intelligent smart devices.

Major POE Benefits

Flexibility and scalability- POE devices only require one cable instead of two. This allows POE devices to be placed areas without power and can easily be re-positioned. More devices can easily be added and adjusted.  

Time and cost savings- it reduces the need for the installation of electrical power cabling and outlets. POE can be used over existing copper complete infrastructure, making installation even easier for scaling IT networks.

Safety- Less electricity cabling is used and POE devices are usually lower voltage. POE delivery is also intelligent, and designed to protect network equipment from overload, under powering, or incorrect installation.  

Reliability-POE power comes from a central compatible source, rather than distributed adapters. It can be backed-up by an uninterruptible power supply or controlled to easily disable or reset devices.