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Wireless VoIP Phones Can Learn A Lot from Plain Old Cell Phones

Wireless voice over IP is the latest in next-gen telecom, but it has a ways to go to provide the same capabilities and reliability as plain old cell phones.

Most telephone users can call 911 and know that emergency services can find them. If they're tethered to a wall, they can switch long-distance carriers without buying a new phone. If they're wireless, they can travel miles, or at least a few blocks, without a dropped call. VoIP--and especially wireless VoIP--doesn't provide those capabilities yet. As VoIP matures, it's moving from touting flashy convergence features to more mundane concerns such as call quality.

The star of last week's VON show for VoIP and IP communications was D-Link's DPH-540, touted as the first Wi-Fi flip phone. It looks and feels like a cell phone but works off a wireless Internet connection. And it's also among the first wireless VoIP phones to include technologies such as wireless multimedia aimed at improving call quality by prioritizing voice over data. Although it can be used from some wireless hot-spots, it's designed for those needing mobility within a home or small office.

Like most Wi-Fi phones, the new D-Link model isn't a practical business option. It doesn't give users an easy way to authenticate to public hot-spots. And like every other Wi-Fi phone, even those aimed at businesses, it doesn't support Extensible Authentication Protocol, the security standard common in enterprise Wi-Fi networks.

The greatest problem for wireless VoIP is coverage. "With a Wi-Fi network, you're stuck inside one building," says David Dean, telecommunications system engineer at Cedars-Sinai Medical Center in Los Angeles. The earliest adopters of VoIP over Wi-Fi have been hospitals, because the relatively powerful transmissions from cell phones can interfere with medical equipment. But Cedars-Sinai rejected VoIP. Dean instead installed an indoor microcell from LGC Wireless, to ensure that people's Sprint and Cingular phones could transmit at the lowest possible power. "We have a Wi-Fi network for data, but we stuck with cellular for voice because we need mobility outside," he says.

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