POE injector is an elementary network device, which greatly simplifies the installation of network devices in the enterprise or in the office. POE technology (PowerOver Ethernet) allows powering network equipment through a network cable, thereby relieving users of this equipment of the need to install electrical outlets in places where it is inconvenient, as well as the use of bulky power supplies.
Let's look at the benefits of a device like a POE power injector. When installing a Wi-Fi access point, network camera or router in the office, you need to consider where the nearest outlet (220 volts) is located in order to connect power supplies from the listed equipment. Often this can significantly limit your ability. Very often, in order to get the best Wi-Fi signal, you need to place the access point higher, for example, under the ceiling. In this case, you must either lay the wiring and install a new outlet under the ceiling, or sacrifice the signal quality and install the equipment where the power allows. And if you need to install network equipment in hard-to-reach places (on the roof, attic, and so on), then in this case the cost of wiring and installing outlets can be very high. To solve this problem, the IEEE 802.3AF standard was created, which allows electric current to be transmitted over the Ethernet network. To ensure the operation of the devices, existing cables of the third or fifth category are quite sufficient. Unlike the 220 volt network, where electricity is supplied to all power consumers, the POE injector distributes power individually to each device.
Since all computer equipment is powered by direct current, the POE standard implies the transmission of twisted-pair direct current cable with a voltage in the range from 44 volts to 57 volts via cable. This value was chosen because it can be supplied via twisted pair cables without restrictions on duration. To transmit electric current , two pairs are allocated in the cable, a current of 175 milliamps (a total of 350 mA) is supplied through each of them. Accordingly, the power of a device such as a POE injector can reach 16 watts. This is more than enough to power network equipment.
In fact, a POE injector is a device that transfers electrical power to a signal cable . This device can be embedded in network equipment (routers) or be made in the form of a standalone device. In the latter case, the POE injector is connected through a twisted pair section and to a 220 volt network. The input of this device receives only data, and already at the output - electric voltage and data.
In conclusion, we add that POE technology was conceived as an opportunity to reduce costs when pulling networks in offices and enterprises. However, it quickly gained popularity in the private sector, because it greatly simplifies the connection of network equipment and eliminates a large number of unnecessary power supplies.