What Is E911 and How Does It Work?

Everything you need to know about Enhanced 911

When you dial 911 during an emergency, it's vitally important for the 911 dispatcher to know where to send the police, fire truck, or ambulance. Enhanced 911, or E911, is a feature built into smartphones that automatically gives the GPS location of the phone to the dispatcher. Learn more about what E911 is and how it works.

The information in this article applies to all cellphones manufactured in the United States.

How E911 Calls Work

GPS location is vital in situations where the mobile caller is unable to provide the location. Enhanced 911 is a process that happens automatically when a 911 call is placed from a mobile device. It doesn't require any special effort or code on your part to access the service.

When an E911 call is made, it's routed to a Public Safety Answering Point (PSAP), a call center operated by the local government. PSAP dispatchers pull the name and billing address, the physical address, or (in the case of a mobile caller) the geographic coordinates so that they can direct the emergency responders to the correct location.

A stranded traveler calling roadside service
ViktorCap / Getty Images

911 is the number to call for emergencies in North America. If you visit another country, memorize the appropriate emergency contact numbers for that region.

How E911 Evolved

The Public Safety and Homeland Security Bureau, under the Federal Trade Commission (FTC), is in charge of improving public safety through U.S. national communication systems for emergencies, including 911. As communication technology continues to evolve, the U.S. 911 system needs periodic upgrades to match these technological advancements.

For example, when the first 911 call was placed in 1968, there were no cellphones. All phones were tied to a physical address, which 911 dispatchers could access from telephone company records.

Before E911, a 911 call made on a mobile device would go through its mobile service provider to get verification before the call was routed to a PSAP. The FCC now requires that all 911 calls must go directly to a PSAP. These calls must be handled by any available phone service carrier, even if the mobile phone is not part of the carrier's network.

Getting More Specific Location Through E911

As another way to improve the 911 service, the FTC mandated that all cellular telephone carriers provide more accuracy to PSAPs in locating a caller's location. The first phase, enacted in 1998, required all mobile carriers to identify the originating call's phone number and the location of the signal tower, accurate within a mile.

In 2001, the second phase of the program required that mobile carriers provide a latitude and longitude (X/Y) for 911 callers' locations. This location data is accessed through the GPS chip on the mobile phone, which can only be activated during a 911 call. These E911 rules apply to all wireless licensees, broadband Personal Communications Service (PCS) licensees, and certain Specialized Mobile Radio (SMR) licensees.

Limitations to E911

While the X/Y coordinates can help dispatchers find your approximate location, there are limitations. For example, these coordinates aren't helpful if the call comes from a multi-story building. The Federal Communications Commission (FCC) is now requesting that carriers provide vertical coordinates, or a Z-axis location, to more accurately pinpoint where a caller is located.

E911 may not be enough to help 911 dispatchers find your location quickly in an emergency. The FCC accuracy standards range from within 50 to 300 meters, which could cost responders valuable time when finding you during an emergency. For these reasons, provide the 911 dispatcher with as much information as possible.

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