A power over Ethernet injector is a circuit device that allows the transfer of both data and power over single cabling in a system. The injector supplies power to circuits in accordance to the IEEE standards and is used in network routers, network webcams, VoIP phones, network time protocol wall clocks, hallway amplifier speakers, mini network switches, wireless access points and network systems such as intercom, paging and public address.

The use of the power over Ethernet injector in PoE circuitry is preffered due the numerous advantages it offers. The PoE injector will help in lowering the cost of cabling since the systems use a single cable, which in normal conditions would be impossible. The normal circuits would have to use two cables or the USB connection which delivers less power than the PoE injector. In use the injector uses the category 5 cable which is cheaper than the use of USB repeaters, plus there is the added advantage eliminating the need of meeting the building requirements to run an AC cable.

When it comes to data the use of the power over Ethernet injector allows system to transfer data as high as a Gigabit of data per second, one of the highest data transfer levels ever attained. The data can be transferred to every device that is connected to the network thus making it quite easy for applications such as video conferencing and video mainstreaming. This level of data transfer exceeds the 2009 USB and AC power line networking capabilities.

The use if the power over Ethernet injector in PoE circuit also helps in the direct injection from standardized 48 volts powered direct current (DC) battery arrays. This helps in putting up[ of infrastructure in times when there is low power supply, such as when there is a power outage, thus this means that power rationalizing doesn't affect the PoE devices as they would normal systems.

There is also the advantage of uniform symmetric distribution I both power and data. This is a technology that has surpassed the USB technology in that power can be supplied at either end of the cable and transferred to the other end, unlike USB connections where power is transferred from the female to the male connectors. This makes it possible for the determination of the power source after the installation of cables and outlets.

One need not worry that their system doesn't have a power over Ethernet injector; it can be converted into a PoE compatible system by installation of a DC tap.