As target locations for video displays and other devices farther away from AC wall outlets, A/V installers face the challenges of providing power in an affordable, convenient, and safe way.
For example, for digital signage and wayfinding displays in airports and hotels, video displays in medical facilities; even, for consumers, displays in kitchens and other areas of the house.
IT and Facilities have been able to solve the power problem for many wireless LAN Access Points, digital security cameras, and other networked devices thanks to 802.3af Power over Ethernet (PoE) and its higher-power sibling 802.3at Power over Ethernet Plus (PoE+), which conveys power over the same CAT5 or CAT6 LAN cabling used to carry data, eliminating the need to provide standard AC power.
A/V faces many of the same power-related concerns and constraints — and Power over HDBaseT (POH) promises to similarly resolve them, in many situations, bringing PoE-type solutions to the A/V world.
HDBaseT technology is a digital connectivity solution supported by the HDBaseT Alliance, which was started in 2010 by LG Electronics, Samsung Electronics, Sony Pictures Entertainment and Valens Semiconductor.
According to the HDAlliance website, HDBaseT can, as its “5Play” feature set, carry:
all through a single 100m/328ft CAT5e/6 cable with RJ45 connectors.
The signal combining alone is significant, reducing the cable clutter needed to connect a single video device, just like digital security cameras need only one Ethernet connection where their analog CCTV (Closed-Circuit TV) predecessors needed separate cables for video, audio, control signals and power.
In terms of power, according to Micha Risling, HDBaseT Alliance marketing chair, “POH, the Power over HDBaseT standard, is based on the IEEE 802.3at standard, with the appropriate modifications to enable safe delivery of up to 100 watts over the four-pairs of the Ethernet cable.”
Some products using HDBaseT are available — in particular, professional video distributors, HDMI/HDBaseT converters and devices like Microsemi’s PowerDsine midspans. However, since POH is relatively new — it was formally added to the 5Play feature set in September of 2011 — many POH products are still in the pipeline, according to Risling.
As with PoE, key vendors are working to jump-start POH usage by offering Power Supply Equipment (PSE), including “midspans” (a.k.a. injectors) that put power into an HDBaseT cable, “splitters” that extract the power from the cable to go to the power port. Next will be Powered Devices — products that can extract the power from POH, internally, and PSE-enabled products.
With PoE, the power-injecting device is usually a network switch or a midspan injector. “The topology we have in mind to put the power onto HDBaseT will be a kind of A/V receiver,” says Risling. “Today’s receiver connects source devices for video, and redistributes the video, along with control signals and Internet connectivity to display units, so why not also distribute power to these displays?
Currently, you probably won’t find an HDBaseT product that also sends the power defined by the POH definition, Risling says. “You’ll find some that deliver relatively low power — perhaps a few watts, only enough to power a remote extender. Others will implement PoE rather than POH.”
Daniel Feldman, vice president of Business Development, Microsemi Corporation, a