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Air Supremacy

Convergence of cellular and Wi-Fi helps mobile computer users broaden their horizons.

Time is precious for the 70 hospice nurses at Frederick Memorial Hospital in Frederick, Md. They’d much rather spend their hours comforting patients than tracking down patient records. But they need to do both.

That’s why the palliative-care workers now use notebook PCs equipped with cellular modems. Using cell modems embedded in their Panasonic notebooks, they can log on to the hospital’s virtual private network (VPN) and access patient records from nearly anywhere in the county.

“These nurses don’t work 9 to 5,” explains Douglas Smith, senior network technician for Frederick Memorial Healthcare System, which runs the hospital.

“They often have to visit a home in the middle of the night,” he says. “That used to require a trip to the hospital to look at patient records. Now, they can usually do it onsite, without worrying about whether the home has an Internet connection.”

Such flexibility is making cellular modems one of the hottest technologies among business users since the introduction of Wi-Fi, the technology used by most small wireless networks. Worldwide sales of cell modems in 2007 hit $2 billion — more than double the level for 2006, according to Dan Shey, principal analyst of business and consumer mobility for ABI Research, in Oyster Bay, N.Y.

Wi-Fi is not going away, though. Most notebooks sold today come equipped with a Wi-Fi modem, and now the latest handheld devices are following suit. In late March, AT&T and T-Mobile each introduced BlackBerry devices that let their subscribers access the Web over the carriers’ branded Wi-Fi hot spots as well as their cellular networks. That gives remote and mobile workers a choice between Wi-Fi, which can transmit data fast over shorter distances, and cell modems, which are slower but have greater reach.

One advantage of cell modems is that they can be used in more business settings because cell towers reach more mobile users than Wi-Fi access points.

“The only limitation for our users is the cell service signal,” says Jeff Caudill, IT operations manager for Baltimore law firm Gallagher Evelius & Jones.

Caudill supports about 110 users, roughly 10 percent of whom have notebooks. He says he keeps a pool of cellular modems and typically checks them out when his users travel with notebooks.

“The great thing is that the users aren’t tied to the local Wi-Fi network,” he says, adding that the cellular modems alleviate hours of help-desk troubleshooting.

“We’ve been using cell modems for about two and a half years,” says Matt Moses, vice president of operations for ZoomSystems of San Francisco, which employs 100 workers and operates more than 350 retail kiosks in airports, malls and department stores. The kiosks stock a variety of goods, including cosmetics and Apple iPods, and cell modems are used to complete credit card transactions.

“The reason we got started with cell modems is that we either couldn’t pull wire for DSL or T1, or when we could, the cost was exorbitant,” Moses explains.

“And the hot spots were often too weak. Now we find we can get a cellular signal in 90 percent of the locations, and we’re not relying on another company to come in and test for service,” he says.


Photo: Nicholas McIntosh
Jeff Caudill of Gallagher Evelius & Jones says cellular modems eliminate hours of help-desk troubleshooting.

More Reliable Coverage

Similarly, for many professionals on the go, cell modems offer more ubiquitous coverage, says Daryl Schoolar, senior analyst with market research firm In-Stat. “They don’t like to mess with Wi-Fi,” he says.

Consider two of the most common users: mobile professionals and fleet dispatchers.

Let’s say a businessperson is traveling on Amtrak’s northeast corridor between Boston and Washington, D.C. This is North America’s busiest stretch of passenger rail, accommodating some 2,600 trains each day. Yet, the only Web access available is when the traveler passes through a heavily populated area, such as New Haven, Conn., or New York City, and comes into the range of an unsecured Wi-Fi network. Then they can get on the Web — but only for a few moments. By using a cellular modem, users can maintain their Web connections for as long as there is a cell tower nearby. They may get bumped off, but not as frequently.

Next, consider how cell modems can help dispatchers track vehicles. In March 2008, Capital City Limousine of Washington, D.C., switched from a GPS-based tracking system that simply told them where their cars were, to one that uses GPS to locate the vehicle and a General Packet Radio Service (GPRS) modem to transmit that data to a Web-based mapping application that shows city landmarks and detailed street-level information. It also helps them keep track of wayward drivers.

“If I have a driver that’s sneaking home during the day or visiting the red-light district, I’ll know,” says Reggie Tymus, president of Capital City Limousine.

Three Considerations

Not all mobile workers spend their day traveling on the interstate. Often, they have a choice between Wi-Fi or cellular. What’s the difference? Data throughput, coverage area and cost are three areas to consider.

Throughput. With Wi-Fi, users can expect speeds of 11 megabits per second for products using 802.11b gear, and up to 54Mbps for 802.11g wireless cards. However, throughput is ultimately restricted by the speed of the network at a Wi-Fi hot spot. So, your users might connect to the wireless modem at a Starbucks in the time it takes to say “latte,” but they might have time to finish the drink if they download a graphics-heavy Web page.

Some wireless devices allow mobile workers to access a complementary technology known as Mobile WiMax that transmits data at speeds of about 2Mbps to 12Mbps at a range of about two to 12 miles, depending on the deployment and the number of users accessing the network at any given time.

In the next year, how will the number of remote workers supported by your IT department change?

49% Increase slightly
37% Stay the same
10% Increase significantly
3% Decrease slightly
1% Decrease significantly

Source: CDW poll of 377 BizTech readers

Cellular throughput depends on the type of telephony technology used, the carrier and the quality of the cellular modem.

The most common telephony technologies in the United States that have the backing of telecom companies are Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA) and Global Systems for Mobile Communications (GSM).

Speeds vary among carriers and technologies. The newest offering, Evolution-Data Optimized (EV-DO) from Verizon Wireless, can download data at 600 kilobits per second to 1.4Mbps, and upload at 500Kbps to 800Kbps. Enhanced Data rates for GSM Evolution (EDGE) promises two-way speeds of 40Kbps for GPRS-enabled devices and 100Kbps for EDGE-enabled devices.

Coverage. Carriers’ coverage areas overlap in many regions. For example, mobile workers in Austin, Texas, can sign up with Sprint, AT&T Wireless, Verizon Wireless and T-Mobile.

Some of the carriers that use the same technology have roaming agreements that let users move between coverage areas for a fee, typically about 8 cents per megabyte of data. For example, Bend, Ore.-based Edge Wireless and AT&T both use GSM for voice and GPRS/EDGE for data. Different technologies aren’t compatible, however. So, if you are connected to your company Web site using Verizon’s CDMA, you can’t then move into a region that uses EDGE, used by Cingular and T-Mobile, and expect to maintain a connection.

In recent months, there has been progress in the move to converge Wi-Fi and cellular technologies to allow mobile devices to switch seamlessly between cellular and Wi-Fi. Some devices, such as the Sprint Mogul by HTC, the BlackBerry Pearl 8120 from AT&T and the BlackBerry 8820 from T-Mobile, let users connect and send data at Wi-Fi hot spots or through a cellular connection. But moving between Wi-Fi and cellular connections sometimes interrupts the transmission, according to user reports. And if the Wi-Fi hot spot does not subscribe to the same Internet service, users may be asked to pay for access.

Other convergence products include routers that use both technologies. For example, D-Link’s 3G Mobile Router and the Linksys Wireless-G VPN Broadband Router can be used as a fixed broadband Internet connection in offices that do not have a cable or DSL service available. In these cases, a notebook or other mobile device accesses the router using Wi-Fi, and the router connects to the Internet using a cellular connection.

Cost. Falling prices on cellular modems and service plans have helped boost usage in the past 18 months. Monthly access costs are coming down at a measured pace, with many data plans available for about $50 per month. That puts them on par with many landline Internet-access fees.

There is a catch: Cellular plans carry premiums for heavy usage. The good news is that the premium is relatively small for data-only use. For example, subscribers to Sprint’s data-only plan for users of mobile broadband cards and USB modems pay $40 a month to send 40MB of data; to send more data, they must pay $1 per MB, up to a maximum monthly $100 charge. However, they could pay $60 a month with no limits on the volume of data they send. Verizon Wireless provides 50MB per month in one of its data plans, and charges 99 cents per MB thereafter. That’s something to consider for users who send graphics-heavy files; a PowerPoint presentation with light graphics can use close to 3MB.

Moreover, users need to be aware of the potential costs when using their cellular modems abroad. In Bermuda, China, Dominican Republic, India and Israel, Verizon charges users $20.48 per MB.

Even in Canada, U.S. Verizon subscribers will pay $2.05 per MB. Subscribers to the AT&T Wireless international plan will pay an extra $25 on top of their domestic plan to send 20MB of data in select countries. In countries not on that list, the price jumps to $19.50 per MB.

“You have to read the fine print in your service plan,” says In-Stat’s Schoolar. “Roaming overseas can get expensive quickly. People don’t realize how big a file can be. So, it’s a trade-off: With cellular, you get a bigger footprint and won’t have to look for hot spots, but it will cost you more.”

IT Takeaway

Here's the skinny on celluar modems:

• Sales of cellular modems are booming because they let mobile workers access company networks and the Internet when they're away from Wi-Fi hot spots. Also, cellular modems can be deployed without needing to access landlines.
• Many plug-in cell modems now let users access either Wi-Fi modems or connect directly to cellular networks. New handheld devices, such as the BlackBerry versions offered by AT&T and T-Mobile, do the same.
• Data throughput varies widely, depending on the technology used in the modem and by the carrier. Coverage areas overlap among some carriers, some of which have roaming agreements in effect. However, many carriers' technologies are incompatible with others.
• Data plans typically have limits on how many megabytes you can send in one month. Users who exceed the limit must pay a premium. International travelers must be keenly aware of where their coverage plan is accepted; roaming charges can be quite hefty.
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May 20 2008 Spice IT

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