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Can You Hear Me Now?

When you dial 911 on your cell phone, there's a good chance dispatchers will have no idea where you are.


Tom McCormack, the 911 dispatch coordinator for St. Louis County, presses the "play" button and out comes the voice of one of his operators answering a call on the morning of June 23:

"St. Louis County 911, can I help you?"


She tries again: "St. Louis County 911...."

A full ten seconds later, the caller's voice finally comes in, but only a fragment is audible: " — into my house."

"Ma'am, your phone is cutting out," the dispatcher responds.

Another five seconds of silence pass before the caller finally comes through clearly: "Hello? Hello? Someone is trying to break into my house!"

Able to communicate with the panicked caller at last, the operator dispatches a patrol car to the scene.

McCormack has saved two months' worth of calls to St. Louis County's main dispatch center, which serves forty of the county's municipalities, including larger areas such as Chesterfield and Eureka. Each follows a similar scenario: urgent requests for help, preceded by a ten- to fifteen-second silence. All of the calls are from cell phones, and all from the same cell phone carrier: U.S. Cellular.

"The first fifteen seconds they're screaming what their problem is and where they're at," says McCormack, adding that his dispatchers may well hang up on a caller in the belief that they've received one of the hundreds of prank or accidental calls the county deals with each day. "We hang up because we don't hear anything. They're rattling off addresses and problems, and we don't hear them."

In the wireless industry, the phenomenon is known as "voice blanking," and it has been a problem on and off since the advent of mobile phones, though as technology has improved, the glitch has become increasingly less common. According to McCormack, cell phones account for more than 70 percent of all calls to the county's 911 dispatch center. (Dan Howard, commander of the communications division for the City of St. Louis, says his crew of dispatchers has not experienced voice blanking with any cellular carriers.)

Jerry Leiby, senior director of network operations for U.S. Cellular, traces the recent uptick in voice-blanking episodes to a chip built into the company's phones in order to comply with a Federal Communications Commission (FCC) requirement aimed at speeding up emergency-response time in the mobile-phone era.

When a U.S. Cellular caller dials 911, his handset connects to Global Positioning System (GPS) satellites that relay the caller's exact latitude and longitude to the dispatcher's computer. But during the time the handset is relaying its location, the audio connection is disabled. The likelihood and duration of voice blanking depends on the caller's location (some places are more GPS connection-friendly than others) and how quickly the 911 dispatcher answers (more rings means more time for the chip to communicate with the satellite).

Complicating matters, the wireless industry's two largest chip suppliers, Broadcom and Qualcomm, are in the midst of a patent dispute over technology that eliminates U.S. Cellular's problem: Broadcom accused Qualcomm of infringing on patents that improve battery life in chips capable of handling audio and GPS signals simultaneously.

On June 7 the International Trade Commission, a federal agency, ruled in favor of Broadcom and forbade Qualcomm to import any new models that use the disputed chips. Qualcomm is lobbying President George W. Bush to veto the ruling, citing public safety as one of its arguments.

Leiby suggests that until the Qualcomm issue is resolved, 911 dispatchers should exercise patience. "One of the things we can do, we can make sure that [dispatchers] are answering 911 calls in a way that [lets the caller] know the call is connected," he says. "They need to say, 'Hold on, we're getting a read on where you're located.'"

The county's difficulties with wireless 911 calls aren't limited to U.S. Cellular.

Incoming calls from Sprint and Verizon cell phones transmit neither a caller's phone number nor his location, despite the fact that in most cases the handsets are equipped with that capability. That owes not to technological glitches but rather to a good old-fashioned spat about money.

The two providers, along with the county, refuse to pay a fee charged by Southwestern Bell, the local landline provider owned by AT&T, to transmit GPS information from the companies' wireless towers to 911 dispatchers' computers.

The FCC has ruled on several occasions that it is the responsibility of 911 dispatch centers to cover such costs. But in St. Louis County, the four other local providers — Cingular, Nextel, U.S. Cellular and T-Mobile — have elected to pay the fee, which costs about $15 per cell signal tower per month.

Officials from Verizon and Sprint say that as soon as the county is willing to pay, their customers' phones will begin supplying the GPS information. McCormack says the county doesn't have the funding to cover the costs. John Taylor, a spokesman for Sprint, noted that it is GPS-enabled at more than 4,000 911 dispatch centers across the country, including the City of St. Louis, which pays the routing fee out of its own pockets.

Jim Garavaglia, the head of 911 dispatch for the city, says his department pays an average of about $1,400 per month in routing fees. The city receives GPS locations from wireless 911 callers from every network except T-Mobile, though Garavaglia notes they will begin receiving that data from T-Mobile in about two months.

Meanwhile, U.S. Cellular has no current plans to inform its customers about the potential voice-blanking problem, says company spokeswoman Kim Furlow. "Not every customer is affected, and we don't routinely update customers on technical issues with 911," Furlow explains. "We do have to file a report with the FCC on a quarterly basis, and that information is public record," she adds.

Leiby points out that U.S. Cellular's phones aren't any less safe than the competition's, in that they relay a caller's precise location to 911 dispatchers — even if an operator can't immediately hear what the caller is saying.

That fails to impress McCormack. "We get hundreds of calls a day where nobody is there," the St. Louis County 911 coordinator says. "If we can't hear you, we're going to treat it as a hang-up. We do not send a car based on no conversation. We don't even call you back."

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