Power over Ethernet, or PoE for short, is a method of providing both data and power through an single Ethernet cable. Power over Ethernet allow devices to be connected to a network through a single cable, which eliminate the need for either a power outlet or power cable for each device. Furthermore, because Power over Ethernet cables provide both power and data to connected devices, you dont need to hire an electrician to install power outlets near each device that Power over Ethernet powers.
Power over Ethernet, however, require certain standards to be met in relation to the amount of power that the standard delivers, as well as the requirements of the devices that are to recieve that power. Power over Ethernet standards has developed over time to provide power to devices that require different amount of power. The earliest standards for Power over Ethernet were developed for devices that required very little power to operate, such as IP phone and webcams.
How Power over Ethernet Works
Because these devices required little power to performing there functions, the early standards of Power over Ethernet provided enough voltage to those devices without issues. Moddern standards for Power over Ethernet, however, provide more power due to the increased power requirements of newer devices, such as pan tilt zoom cameras and large wireless access points. To provide this additional power to the devices, new method to deliver power have been developed and utilized in moddern Power over Ethernet standards.
These methods include utilizing all four pair of wires included in the Ethernet cable to increase the amount of electricity that can be delivered to the device via Power over Ethernet. In order to ensure that the devices are properly supplied with the power that they require to function, it is important to ensure that the power capability of the Power over Ethernet switch are adequate for the power requirements of each device. Each Power over Ethernet device will perform a negotiation process with the Power over Ethernet switch to determine the amount of power that the device requires.
If the Power over Ethernet switch does not provide enough total power to supply each device, the switch may not be able to power each device. Therefore, you should of calculate the power requirements of each device and ensure that the total power requirement of all devices is within the total power budget provided by the Power over Ethernet switch. In most cases, it is a recommended practice to provide a buffer of 20% power to account for power spikes that the devices create at the time of start up.
Quality of the Ethernet cables that are used in Power over Ethernet standards is also important. The thickness and the category of the cables can affect the movement of electricity through the cables. Using thinner and more anciently categories of Ethernet cables may create additional resistance in the movement of electricity through the cables.
Furthermore, the additional heat that these thinner, lower quality cables create may lead to a drop in voltage to the devices that are connected to those cables. Such a drop in voltage is referred to as voltage sag. Voltage sag can lead to the devices dropping their connection or failing to turn on.
High quality and higher category Ethernet cables reduce the resistance to the movement of electricity and ensure that each device receives the proper voltage to power each device. If there are no Power over Ethernet switches available, Power over Ethernet injectors can be used to provide power to a single device. Power over Ethernet injectors are placed between the network switch and the device to be powered by Power over Ethernet.
The injectors combine the data from the network switch and the power from a power outlet in the room with the device. If only a single device is to be powered by Power over Ethernet, the injector can be utilized. However, if multiple devices are to be powered, a Power over Ethernet switch is the better choice.
Power over Ethernet switches allow for power to be provided to multiple devices. Furthermore, managed Power over Ethernet switches allow the network administrator to monitor each device and reboot the individual Power over Ethernet port from a centralized location. Power over Ethernet is a method of providing data and power through a single Ethernet cable.
In order to implement Power over Ethernet into a network, it is important to ensure that the Power over Ethernet switch has enough power to supply each device, to use high quality Ethernet cables to prevent voltage sag, and to ensure that the total power requirements of all devices does not exceed the power budget of the Power over Ethernet switch. By taking these steps, Power over Ethernet can effectively provide power to network devices in an efficient way.