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The Long Haul: Moving HDMI Over Network Wires

HDBaseT was created to overcomes distance limitations of moving HDMI around homes. But you may already be using HDBaseT in commercial installs without knowing it.

Proceed With Caution?

But will HDBaseT be a long-term solution? Some look at the lack of compliant displays and source devices and worry that HDBaseT could go the direction of DisplayPort, which was a good idea at the time, drew development interest from companies that built DisplayPort into their equipment, and then never really took off. (Interestingly, manufacturers are also designing extenders for sending DisplayPort and DVI-D over HDBaseT.)

Another potential problem with current implementations of HDBaseT is that they're proprietary. So, a technology that promoters view as an eventual standard is showing up in devices that can't interoperate.

"We intend to launch a compliancy and logo program," says Micha Risling, marketing chairman of the HDBaseT Alliance. "Eventually, any product that carries the HDBaseT logo will work with products from a different vendors. At the moment, each vendor can choose whether they'd like to do some proprietary solutions. The tricks are more related to controls because they [manufacturers] can use controls in a way that their products won't work with others."

In fact, the Valens chipset offers a slew of ports and capabilities that companies can utilize as they see fit, plus it offers a way for companies to inject their own features, such as proprietary control protocols and commands for managing EDID and HDCP, into the datastream. Similarly, HDBaseT can transmit RS-232, USB, and infrared control, but it doesn't specify how they should be implemented, giving engineers leeway to program their own solutions. Crestron's DM 8G, for instance, sends control signals, including RS-232 and IR, over the Ethernet channel of the Valens chipset. But it uses the actual Valens control channel for other functions. "Whether our implementation can talk to Sony's or someone else's, that's where the HDBaseT Alliance comes in," Jackson says. Plugging in HDBaseT devices from different manufacturers may leave users with some functionality, Jackson says, "But it's not guaranteed."

Moreover, not all manufacturers turn on all the HDBaseT features in their products, including the built-in Ethernet support. And the technology is designed to deliver 100W of power down the wire—substantially more than current Power over Ethernet (PoE) solutions—in order to drive remote displays. But there are trade-offs. Atlona's Chris Bundy says running power can drastically reduce the distance over which HDBase-T is effective.

"If you're going to run power, we recommend runs under 200 feet," Bundy says. "Beyond that, the cable skew starts getting ridiculous."

Regardless of the ways HDBaseT can be integrated into products, not all manufacturers will adopt it. Notably, AV giant Extron does not have an HDBaseT product in the market. The company says that when integrators need to move HDMI over long distances, it recommends using fiber-optic cabling, which has dropped in price. At Integrated Systems Europe in February, the company came out with FoxBox HDMI, a fiber-optic transmitter and receiver set for the long-haul transmission of HDCP-compliant HDMI and RS-232 control signals. Integrators can use it between two points or in conjunction with one of Extron's Fox fiber matrix switchers.

But if promoters of HDBaseT can eventually establish it as an interoperable standard, it may prove to be a powerful, cost-effective solution for moving HD signals in pro AV projects. "Technically we're not far from interoperable HDBaseT systems," Jackson says. "Like with most things in technology, business issues are the limiting factor."


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