The Power over Ethernet standards have important distinctions that designers must be aware of when bringing together both connectivity and power.
In this day and age, where more and more designs need Internet connectivity, design professionals can reduce space by using dual-purpose standards such as Power over Ethernet. This standard (and other ones similar to it) reduces how many ports are needed to run a device. Instead of having multiple ports to provide communications, power, and the ability to debug, a single port is able to create and test processes while preserving a compact dimension.
PoE utilizes the use of two to four pairs within Ethernet cables to transmit power while not affecting the capacity for communication. Image taken as a courtesy of FS
Although Ethernet is not the sole method to connect to a network local to the user, it does provide physical wired connections instead of one that requires a router to work. In this regard, when it comes to systems that require a high level of uptime, Ethernet may be the most reliable choice. Instead of having to have both a power as well as an Ethernet port, certain models are able to utilize the well-developed power over Ethernet standard (PoE).
Three generations are currently available of the PoE standard, each providing users distinct benefits. This article focuses on the distinct characteristics of the three PoE standards in order to provide designers with the information they require to connect power and communications on their own devices.
PoE Puts Comms and Power in One Port
Within the PoE cable, there are four twisted pairs, which is eight in all. Each PoE (IEEE 802.3af) as well as PoEplus (802.3at) makes use of two pairs for transmitting data and another pair to transmit power. PoE+ (IEEE 802.3bt) utilizes the four twisted pairs to transmit both power and data, which allows the transmission of more power at higher watts.
This initial version of the PoE standard that is appropriately called PoE, could deliver as much as 12.95 W to electronic devices that have voltages of 37-57 V. At the time of its introduction (2013), the standard allowed designers to work to design low-powered devices, but was soon changed with that of the PoE+ standard, which provides greater power.
Inside the PoE cable. Image taken with permission of Nelly’s Security
PoE+ is a standard for power distribution. PoE+ standard supplies up to 25.5 W to devices with voltages ranging from 42.5-57 V.
The latest edition of the PoE standard, dubbed PoE++, is a significant rise in the power consumed which allows designers to utilize up to 71 W of power for connected devices with the same voltage. Engineers are able to incorporate PoE into even more energy-intensive designs and offer more flexibility for Ethernet systems.
PoE utilizes the different characteristics of Ethernet cables to permit communications and power signals to coexist, thereby providing the power source without affecting the bandwidth of communications. Image taken from Versa Technology
It’s also important to note that PoE doesn’t affect the speed of transmission (in theory, at the very minimum). Because Ethernet makes use of differential pairs to transmit data, it is possible to increase the voltage in a common mode couple with minimal impact on communications capability.
Choosing a PoE Standard
When deciding on the PoE standard to incorporate in the design, the distinctions between standards make the decision simple choose the one that will provide enough electricity to the gadget. If, for instance, the device is designed to consume less power, PoE will be sufficient for higher-power devices, while larger designs might require PoEplus or PoE+.
Through the use of more twisted pairs, PoE standards have been refined to offer designers greater power capability and PoE support for high-power devices. Image is by permission of Versitron
It’s not the only thing to take into consideration when choosing the right standard. Communication bandwidth could be a factor that can influence what IEEE standards (and that is why the PoE standard) that is to be followed. If it is a power supply that’s the sole aspect to be considered, the easy development to PoE’s PoE standard makes the choice simple.
Simplifying Connected Designs
Although PoE isn’t an all-purpose solution, for situations that require premium or silent power sources, PoE can be an ideal option for seamless connections. PoE simplifies the process of setting up and the subsequent operation using only one port to connect and power.
The number of devices connected is increasing, and PoE standards will likely change to keep up with the demands. However, it is possible that balancing reliable wired connections with wireless ones for devices with less requirements can be an optimal compromise for the future of networking technologies.