WLANs Wireless networking for total mobility

by David Orenstein freelance writer

There are many ways to use a wireless network in your practice. You could take your laptop into the exam room to show a patient information on the Web. You could bring in a hand-held device and access the patient’s record on your network, or keep tabs on your e-mail while you’re in the lunchroom.

These ideas could strike you as life-savers or as totally absurd. It’s up to you to determine how to put new technologies to work for your business. Wireless networks are becoming popular in hospitals and can make total mobility around the office possible—without running cables all over the place. Along with these benefits, however, you must consider security, and perhaps even wireless interference, risks.

The leading technology for wireless local area networks (WLANs) has two names: 802.11b or “Wi-Fi.” Regardless of the moniker, the technology is based on the same networking standard—ethernet—that governs wired office networks. WLANs, however, are slower. On paper, they offer maximum speeds of 11 mbps, but a knowledgeable engineer once told me that in practice, the speed is about half that. Still, 5.5 mbps is very fast—almost four times faster than the most popular DSL connections at their fastest.

To set up a Wi-Fi network, you need to buy an access gateway, which costs about $300. This device is like a transceiver that literally connects your wired network (such as ethernet cables or a DSL line or cable modem) and your wireless network. All data moving around the network goes through the gateway. For each computer you want to wirelessly link to the network, you’ll need an access card, which costs about $125. Vendors of this hardware include 3com, US Robotics, Netgear, and D-Link.

As with any network, but especially a wireless one, make sure you consider security. The access point you buy should include a firewall to foil hackers and offer encryption (to stymie hackers who get past the firewall). Finally, you should make sure that computers cannot join your new network without a password, but that is a requirement for all networks—wireless or not.

What may be less obvious is the issue of interference. Unlike wired networks, wireless ones are prone to getting their signals crossed. In fact, the FCC had to solve a major wireless interference problem in Texas a couple of years ago. A Dallas TV station’s digital TV tests apparently knocked out the signals of medical telemetry equipment at Baylor University Medical Center. To solve the problem of TV and medical equipment sharing the same spectrum, the FCC in 2000 reserved a swath of wireless spectrum for medical use.

What does this have to do with Wi-Fi? Well, after the Baylor debacle, some medical telemetry equipment vendors switched their products to Wi-Fi. There is a chance, then, that such equipment could interfere with a more general office Wi-Fi LAN. This is not a large chance, by any means. Wi-Fi avoids interference by constantly changing frequencies during transmissions. But if you have new medical telemetry equipment in your office, it is worth contacting the vendor of that equipment and the vendor of your prospective Wi-Fi gear to ensure they won’t interefere.

WLANs aren’t cheap, they aren’t fast, they are more difficult to secure, and they run at least a theoretical risk of interfering with some medical equipment. But if you want the freedom to rove about and tap your data anywhere you need to, then say hi to Wi-Fi.

David Orenstein is a technology and business writer in Silicon Valley. If you'd like to learn more about a certain computer topic, e-mail him at davealli@home.com.