Smart Building

PoH and PoE: What Sets Them Apart?

Ron Tellas

Interactive digital signage in a hospitality resort; video screens in airports; wireless access points, security cameras and high-end AV equipment in meeting rooms: they all have one thing in common. These applications use devices and technology that allow the delivery of power and data over twisted-pair cabling.

Power over Ethernet (PoE) technology allows Ethernet cables to carry data and electrical power to networked, IP-enabled devices like those described above. It can also help reduce cabling and installation costs because devices no longer require a data connection and an electrical connection – they just need one data connection to join the network and receive power.


PoE has been around since the early 2000s, so most people are aware of its capabilities and benefits – even if they’re not currently deploying it. But a new version of delivering power and data has entered the scene – Power over HDBaseT (PoH) – and there questions are circling about how PoH is different than PoE. You’ll find the answers here!


The Basics: Power over Ethernet

PoE standards indicate signaling requirements between power sourcing equipment (PSE), which provides power on the cable, and powered devices (PDs), which receive power from the PSE.


The first version of PoE provided PSE power of up to 15.4W and delivered up to 12.95W to the PD. It was used primarily to power and connect VoIP phones, wireless access points and IP surveillance cameras. PoE allows these devices to be placed almost anywhere – even if there isn’t an electrical outlet nearby.


As an updated wireless networking standard – IEEE802.11ac – became reality, these types of devices needed more power. An updated standard (IEEE802.3at-2009) increased PSE power to 30W to deliver up to 25.5W over two pairs to the PD.


The next move is to 4-pair PoE (IEEE802.3bt, which is under development). It will offer two new power levels, providing PSE power of 60W to each PoE port (up to 51W for each device) and nearly 100W of PSE power to deliver 71.1W to the PD.


The Basics: Power over HDBaseT (PoH)

To create the PoH specification, PoE technology was enhanced even further. To function, PoE technology requires that the PDs – cameras, screens or wireless access points, for example – assume a worst-case cabling infrastructure. With PoH, a PD can identify cable length and resistance, and draw power as needed (as long as it keeps overall power consumption at 100W or below). PoH is comparable to PoE for delivery of power 30W or less when two pairs are used.  For higher power delivery, PoH is unique to the HDBaseT standard to bring more power to the devices that require it.


For spans of up to 100 m, HDBaseT technology brings uncompressed full high-definition digital audio and video, 100BaseT Ethernet, USB, power and various AV control signals together using a single network cable and RJ45 connectors. The PoH standard was created by the HDBaseT Alliance in 2011.


PoH delivers up to 100W over all four pairs in a category cable. By using all four pairs, two power interfaces are available to provide twice the power offered by two-pair solutions. If multiple PDs need power, PoH allows devices to be daisy-chained together and all powered through higher-power extenders (95W).


Belden Prepares You for PoH and PoE

As the HDBaseT Alliance continues to work on enhancing PoH capabilities, Belden will keep you updated. We can also help you make sure your cabling infrastructure is ready to support PoE and PoH. Check back soon as we share news about our PoH-rated cables and HDBaseT Authorized Training.