How-To: Setting Up Wireless Presentation Systems

If your offices are full of projectors and wires, it may be time for a clean-up job. We give you the lowdown on how to build a wireless presentation system

January 13, 2006

10 Min Read
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First, Add a Card

Step-By-Step ScreencastsClick on the images below to launch video screencast presentations of wireless presentation tools.

Linksys Demonstration

Elluminate Demonstration

So how do you cut the wires in your presentation system? One of the easiest methods is to buy a compatible, add-on wireless card ($150 to $300) from your projector vendor. Although wireless projectors are relatively new to the market, many nonwireless projectors are now coming standard with PCMCIA slots designed to accept a compatible wireless network card. We tested the NEC LT265 series nonwireless projector with the NWL-100A wireless add-on ($159). The projector plus add-on comes to $3,154.

The steps to set up the NEC system range from basic to complex, depending on whether the system is being integrated into an existing wireless infrastructure or used on its own. The quickest way to get the projector up and running is to use the Easy Connect mode, which actually creates an 802.11b ad hoc wireless network. Users must install the NEC Image Express Utility (available for Windows and Mac OSs) included with the add-on card. The utility automatically configures your laptop's wireless connection and looks for compatible projectors in range. The main trade-off with this method is that users don't have access to the Internet or their corporate network because their wireless card is connected solely to the projector.

Alternatively, you can connect your projector to your organization's existing wired or wireless infrastructure. If you choose to connect to your wired infrastructure, the projector has a 10/100 Ethernet port with more bandwidth than any wireless connection could provide. If an Ethernet cable run is not feasible for your organization, place the projector in Infrastructure mode, where it acts as a wireless client and connects to the wireless network you specify. With either approach, the goal is to connect the projector to your existing network, which serves as the path over which the projector sends the screen images.

The presenter connects (either wired or wirelessly) to the network on which the NEC projector is installed. He or she installs the NEC Image Express Utility, selects the projector, and the presenter's screen is mirrored automatically. This more complex deployment lets clients simultaneously access other resources--the Internet and your corporate network, for instance--in conjunction with the projector, and also make presentations on the projector from anywhere on your network.

System performance depends on the connection method you choose as well as your presentation content. Easy Connect's speed is limited to 11 Mbps, whereas Infrastructure mode tops out at 54 Mbps. The best performance is obviously with a 100-Mbps Ethernet network. At any speed, the NEC system excels at PowerPoint presentations, image slide shows and other situations in which the screen contents are relatively inanimate.

But for full-screen videos and complex animations, slower connections can introduce unwanted latency and reduce the overall frame rate, rendering them unwatchable, so it's best to use Ethernet when possible. If you want full-screen, DVD-quality real-time video, connect to the projector using a conventional VGA cable.

Once you deploy the projector and install the software, using the wireless presentation system is intuitive. It's worth the trouble to install the required software on every participant's laptop, because it includes features that make your presentations interactive, such as chat, file sharing and image capture.

Security for the NEC wireless presentation system depends on the connection method you've selected for the projector. WEP (Wired Equivalent Privacy) is the highest level of wireless encryption the NEC device supports while operating in Infrastructure mode, which is insufficient for enterprise environments. For a more secure method, connect the projector through the wired interface to your network, thereby using stronger encryption standards such as WPA (Wi-Fi Protected Access).

If your existing projector doesn't support a wireless add-on and a complete hardware upgrade is not an option, there are a few niche products that can make legacy projectors wireless. These products consist of a small hardware appliance resembling an AP (access point) with a VGA output. The price is about $300.

A software app on the client side of these VGA appliances transmits the presenter's screen to the appliance. Beware that the client apps are generally Windows-only and you must install them on every participant machine.

We tested Linksys' WPG54G Wireless-G Presentation Adapter to evaluate how it turned one of our legacy projectors into a wireless workhorse. Setup is straightforward, starting with the VGA connection to the projector. In order to project their screens, users make a wireless connection to the presentation adapter, which operates as an AP broadcasting an SSID (Service Set Identifier) with the prefix WPG54G.

Once the requisite Linksys WPG54G control utility is installed on the presenter's machine, it scans the local network for compatible presentation adapters. When a connection is established, the user can transmit his or her screen wirelessly. If your presentation adapter is connected to an existing wired infrastructure through its Ethernet port, the adapter functions like a conventional AP, facilitating wireless access to both the presentation functions and existing services on the network.

The appliance's performance will vary depending on your connection speed and screen contents. The software behind the scenes in the WPG54G control utility is an open-source, remote desktop protocol called VNC (Virtual Network Computing), in which the presentation adapter acts as the VNC client and the presenter as the VNC server. Its performance is similar to that of other remote-control solutions: It performs well with PowerPoint presentations and slide shows, where the screen contents are slow to change, but real-time applications like movies and Flash animations can be jittery and obscured. In our tests, a simple PowerPoint presentation got an average of 1 Mbps throughput and a full-screen movie was closer to 4 Mbps, but with an unacceptable jitter. The obvious problem is insufficient bandwidth in the wireless connection.

We found the security of the Linksys presentation adapter insurmountably deficient due to its WEP-or-nothing security options and inability to restrict presenters. Any user with the appropriate software can join in using the appliance without a security clearance. This may be fine for small, trusted meetings, but a large lecture can be easily disrupted if a malicious user displays unwanted content on an overhead projector.

The appliance's overall feature set and security is acceptable for small offices, but in larger deployments, the lack of multiplatform support may alienate users.

If you're looking for more advanced wireless presentation features--including support for multiple client platforms--you can deploy some higher-powered presentation applications such as Elluminate Live. Elluminate Live is similar to Microsoft NetMeeting or WebEx, but designed for distance learning and virtual collaboration. It comes with an application-sharing feature that allows the meeting presenter to transmit a specific program or the entire desktop to other participants, including a projector if it is directly cabled to an Elluminate Live client.

Although the product is simple to use, the process of integrating it into a wireless presentation system can be complicated. We don't recommend it unless you have an existing wireless network that will allow connectivity between an Elluminate server and client.

Elluminate offers versions to suit any size application --the team edition license, for instance, comes in 3-, 5- and 10-seat options, starting at $2,400 per year, while the enterprise edition runs around $800 per seat per year. The actual back-end for Elluminate Live is a multiplatform server application that hosts the meetings and facilitates communication between Java clients. You can install the Elluminate server on a dedicated machine in your network or have Elluminate host it off-site.

Wireless Presentation FeaturesClick to enlarge in another window

Unlike the ad hoc Linksys and NEC presentation systems, Elluminate Live requires that an administrator preplan meetings. After a moderator has created a meeting on the Elluminate server, users join by connecting to the Web site provided by the moderator. They can then instant message, whiteboard, use the VoIP capabilities for real-time conversations and share their applications.

To share applications on a projector, one participant must have a VGA output connected directly to the projector. By custom-building a dedicated Linux or Windows system that's permanently cabled to the projector, you can install the entire system much like the Linksys adapter. This dedicated system becomes a permanent member of an Elluminate meeting, letting users share applications by mirroring them on the projector. Elluminate Live clients don't have to be located in the meeting room to attend the presentation--they can connect from anywhere on your network or over the Internet.

How secure is this wireless presentation system? That depends on the encryption settings of your wireless network. Since most Elluminate clients are connected wirelessly to a meeting, be sure to use dynamic key-based encryption for meetings with sensitive content. You also can add access control with password protection, and the meeting moderator has the power to define who can and can't share applications.

Your performance will vary based on the bandwidth between the Elluminate client and server. The product was designed with low-bandwidth users in mind, so you can adjust compression and optimization settings to meet any specific connection-speed limitations. If you connect the Elluminate server directly to the local network, the quality and update speed of the application-sharing feature is sufficient to support nearly real-time presentations.

If you want to cut the cord for wireless presentations, it's important to select a system that best meets your organization's needs and to configure it properly. Many turnkey products, like the Linksys adapter, are sufficient for wireless presentations, but are seriously lacking in security and multiplatform usability. If you require more security and advanced features, products such as Elluminate Live or add-on options from projection vendors are your best bet, as long as you take the time to integrate them tightly into your networking infrastructure.

Jameson Blandford is a lab associate at the Center for Emerging Network Technologies at Syracuse University. Write to him at [email protected].

The wireless presentation systems on the market are dominated by offerings from projector vendors. By simply adding a wireless card or Ethernet connection to their standalone projectors, suppliers like InFocus, Epson and NEC can make their products wireless. Their add-on solutions include wireless access cards for the projector and software applications for the presenter's machine. The software acts as a desktop mirroring program by sending a screenshot to the projector at regular intervals.

As wireless presentation systems gain traction, SOHO vendors like Linksys and D-Link have begun to offer vendor-neutral produtcs designed to work with wired projectors. These special-purpose AP-like devices interface directly with the projector's VGA port and are compatible with almost any projector system. They use client screen transmission software applications to transmit screen images from presenter to projector, much like the products offered by the projector vendors.

There also are software packages for distance learning and online meetings. Similar to Microsoft Netmeeting and WebEx Meeting Center, Elluminate Live was developed for e-learning and collaboration. But it also includes a valuable feature called application sharing: By sharing a specific application such as Microsoft PowerPoint or the whole desktop, the presenter can share his screen with everyone in the Elluminate session. You can add a projector by connecting a dedicated computer to each projector installation, so that presenters are not required to be in the same room physically but can share their displays from anywhere on the network.

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