Cutting the Cord

Wireless should be a perfect fit for installations that need to be fast, clean and neat. So why is it still a niche technology? Tim Kridel finds out.

The percentage of enterprises that have upgraded their PCs to Windows Vista is in the single digits, according to a July 2008 Forrester Research study. In the U.K. market, a May 2008 Computer Business Review survey of IT managers found that about 2 percent had upgraded, a figure that Microsoft said matches its estimates.

That adoption affects the market for wireless enterprise AV products, particularly projectors. Here’s why: It’s often difficult to walk into a conference room, turn on your laptop, have it search for the wireless projector and then connect. By comparison, it’s relatively straightforward to find and connect to a corporate wireless local area network (WLAN) or public “hot spot” using 802.11 Wi-Fi.

In fact, some integrators and vendors say that this basic process of finding and connecting is so difficult that it’s helped stymie the market for wireless AV products. Some AV vendors have addressed the lack of plug-and-play functionality by providing software that clients install on their laptops to automate the task of finding and connecting to a display or projector. But that approach has a few drawbacks:

Some enterprises are reluctant to allow more software to be loaded onto employee laptops, if only because it increases the chances of conflicts that could cause the notebook to crash. On older, less capable laptops, the software also could tax the processor and memory, undermining performance, especially when running a slide presentation at the same time.

The software would have to be provided to non-employees, such as visitors who want to use a conference room’s projector to make a presentation. That’s even more of a problem in convention centers, where nearly every user is a visitor. And even if the software is available, the user might not be able to install it because of the way that their employer has configured their laptop. “Maybe they don’t have the administrative rights to add that software,” says Rich McPherson, a product manager at NEC Display Solutions.

It’s here that Windows Vista comes into play. Just as previous versions of the operating system automatically found printers on a network, Vista adds the ability to find and connect to projectors on a network – including wireless ones.

“You don’t need a software suite residing on your computer,” says McPherson, whose company worked with Microsoft to add support for its projectors. “It’s built into the [operating] system.”

But one catch is that as a result, adoption of wireless AV products hinges partly on enterprise adoption of Vista. If more enterprises decide to hang onto their existing laptops until the economy rebounds, Vista could remain the exception rather than the rule. And with Vista’s successor possibly due for release as early as the second half of 2009, some enterprises may skip Vista and just wait for Windows 7.

In the case of conference room projectors, another concern is the impact on laptops – and not just in terms of adding software to facilitate connections. Depending on the laptop, pushing video over Wi-Fi can be a real struggle, to the point that it’s noticeable.

“The CPU on the notebook gets all consumed with trying to keep up with pushing video, and you wind up with jerky video, even with today’s high-performance notebooks,” says Mitch Friend, senior vice president and general manager at Avocent.

[x-head]Why Wi-Fi?

[text]Wi-Fi should be a natural fit for AV applications such as digital signage, particularly in places – such as malls and airports – where jackhammering up the floor to run cables to new displays isn’t an option. That hurdle can be even bigger when the client leases the space, requiring the landlord’s permission to install cables.

As digital signage becomes common in more places – from atop gas pumps to above urinals in night-club restrooms – so does the likelihood that integrators will have to get creative in terms of getting video to those displays. Even if snaking cable, say, through a drop ceiling is an option, it might not be the best one.

Yet another issue is how the space is used. For example, if it’s a store, the client might want the work done only between closing and opening – odd hours that can mean labour surcharges.

By comparison, Wi-Fi often can be installed faster and thus cheaper. For example, Avocent says one integrator using its wireless products saved more than $5,000 (€3,850), while another installation took just three hours.

[x-head]Why not Wi-Fi?

[text]But not all integrators and vendors are sold on Wi-Fi. One common concern is reliability.

“Dealers have told me they would not spec a wireless video distribution for their clients due to the reliability factor,” says Kevin Schroll, senior product planning manager at Sharp.

For example, Wi-Fi signals have a range of about 100m, depending on the version of the 802.11 standard. However, that distance can be reduced by half or two-thirds depending on physical obstructions, such as walls, and on interference from microwaves, cordless phones and the client’s existing WLAN. All of that can produce an intermittent signal, cut the bandwidth down to the point that it struggles to handle video or both.

“Connectivity is real problematic for some digital signage packages in that if they can not touch the network for a period of time, the player goes to a blank screen or locks up,” says Mike White, CTS, president of Multi-Media Solutions, a U.S.-based integrator, and governor-at-large
for Infocomm. “Of course, the better players and packages do not do that, but [it’s] a reality for some.”

Another factor that can affect reliability is whether the signage piggybacks on the client’s existing WLAN – perhaps to reduce hardware costs – or has its own, dedicated WLAN. If it’s sharing the client’s WLAN, then the ability to get video out to each display in a timely manner is at the mercy of other traffic on the WLAN.

For example, if employees routinely send 20 MB files to one another over the WLAN, plus the usual load of e-mail and even voice telephony, there might be not be much bandwidth left over for the signage application. That’s just one of many issues to consider when assessing whether the client’s WLAN can reliably support digital signage. But finding out can be a challenge.

“Many locations that say that their network can be used have no idea of existing bandwidth,” White says. “Some don't even know their own passwords, and certainly there is security exposure.”

In fact, security concerns are a major reason why some enterprises won’t allow signage, projectors or other AV gear onto their WLAN.

“Those guys are always sensitive to anything that’s going to be on their network,” says Avocent’s Friend.

Some clients have other reasons for not wanting to put AV gear on their WLANs.

“Usually they don’t want it connected to the network because they want just that specific room to have access,” says NEC’s McPherson, whose company currently has six AV products with embedded wireless.

[x-head]Staying Separate

[text]Even if there’s a separate WLAN for signage, projectors and other AV gear, bandwidth, range and reliability remain concerns. It’s here that the choice of Wi-Fi technology can be critical.

For example, the 802.11b version of Wi-Fi – the most widely used – runs in the 2.4 GHz band. So if the client already has a WLAN that uses 802.11b, it might make sense to run the AV applications over a different version of Wi-Fi, simply to avoid interference, which can reduce bandwidth on both networks. One option is 802.11a, which uses the 5 GHz band.

“One of the reasons why we’ve operated in 802.11a versus 802.11b and 802.11g is then we’re pretty much guaranteed that we’ll stay away from all of the WLAN traffic,” Friend says.

Besides avoiding interference, the choice of Wi-Fi standard affects performance and reliability in other ways, too. For example, one reason why 802.11a and 802.11g are popular is because they provide more bandwidth than 802.11b: up to 54 Mbps versus 802.11b’s 11 Mbps. Bandwidth directly affects the ability to support applications such as video.

Different Wi-Fi technologies also have different amounts of channels available, based partly on what the standard supports and partly on what regulators in a particular country allow. So if there’s a lot of interference – a good possibility in a public place such as airport or office building – then the integrator may have more options with a technology such as 802.11a for moving the AV traffic to a clear channel. (For more details about each 802.11 technology’s capabilities, visit

However, one caveat applies to all Wi-Fi technologies: Roughly half of the maximum bandwidth is eaten up by radio overhead, with the remaining amount potentially whittled further by factors such as physical obstructions, distance and interference.

[x-head]N is for newcomer

[text]One way to improve the chances that enough bandwidth will be available is to use the Wi-Fi technology that supports the most. That’s 802.11n, which supports peak speeds of 300 Mbps.

The big catch is that the 802.11n standard hasn’t been officially finalised and approved by the Institute of Electrical and Electronics Engineers (IEEE) and probably won’t be until sometime in 2009. But that hasn’t stopped makers of laptops and WLAN hardware from shipping 802.11n products.

In fact, many of those have been available for more than two years. That’s noteworthy because it means there’s now a large and growing installed base of 802.11n products in the enterprise space. So if a client has already deployed 802.11n, then it might make sense to use that technology in, for example, projectors or displays.

Avocent’s MPX1550 wireless extender is one new pro AV product that supports 802.11n. Aimed at signage applications, the MPX1550 features three antennas, which highlights one of 802.11n’s benefits: The standard uses multiple-input, multiple-output (MIMO) antenna technology to help work around interference and weak signals, thereby improving reliability and bandwidth.

The MPX1550 also shows how the choice of wireless standard affects the types of video that can be supported, such as HD.

“On the wireless side, we limited that to 20 Mbps maximum bandwidth [on its predecessor],” Friend says. “With the 1550, we’ve increased that 450 percent to 110 Mbps in a [one-device-to-one-device] scenario.”

That enables loss-less video, which can be a decisive factor for some applications.

“Around 110-120 Mbps, it’s equivalent to a cable,” Friend says.

Tim Kridel
Tim Kridel is a free-lance writer who covers technology and telecom for a variety of publications and analyst firms. He’s based in the U.S. city of Columbia, Mo., and can be reached at

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