Reverse Phone Lookups On 911 Calls

Did you know that reverse phone lookups are run by 911 dispatchers 250 million times each year? Since it was first established in 1968, the 911 dispatch system has saved the lives of millions of Americans. Most of us take for granted that when we dial three simple digits, someone will answer, trace our location, and send help quickly. But how does that actually happen?

First off, it's worth pointing out that there is no national 911 system. All of the 911 dispatch centers are established and maintained by local municipalities or counties. Today there are more than 6000 Public Safety Answering Points (PSAPs), which is where local telephone companies route 911 calls.

Anyone who has seen a crime drama on TV knows that it takes at least a couple of minutes for the cops to trace the phone call of an unknown caller. So how can 911 dispatch do it so quickly? Reverse phone lookups on 911 calls are not magic, but they do require some special technology. Let's take a look at the mechanics of a 911 call.

1. For any phone call placed via the public-switched telephone network, a number is identified and recorded by the phone company (it's how they bill you for your calls). When you place a 911 call, your phone number is passed to the 911 network through a process called Automatic Number Identification (ANI). This is the reverse phone lookup method that the dispatchers use. 
2. As a subscriber to a phone company, you provide contact details such as your name and billing address that are available in a reverse phone lookup. This information is maintained in an Automatic Location Identification (ANI) database and is also made available to the 911 dispatch network.
3. Phone companies and public safety agencies have long collaborated to create what's known as a Master Street Address Guide (MSAG). This electronic guide cross-references every phone number in the database with a street address and subscriber information, which allows for fast and accurate reverse phone lookups.
4. When a 911 dispatcher receives an emergency call, all information about the caller is provided onscreen, emergency responders can be sent to the address.

The basic 911 reverse phone trace process has been operating in this way for decades. However, with the increased use of cell phones and voice over IP (VoIP) devices, the 911 system has been forced to update the way it identifies emergency caller information. 

Enter Enhanced-911.

When a call is sent to 911 from a cell phone or other mobile device, its exact location isn't immediately known. Cell phone reverse lookups are more challenging. That's why safety agencies reached out to the FCC to create a new set of rules for wireless carriers. This enhanced 911 system requires wireless network carriers to provide similar information as landline carriers, with additional location information based on cell tower signals.

The FCC also mandated that by 2018, all wireless network carriers must provide cell phone GPS tracking location information when a call is placed to 911 so that exact locations for unknown callers can be given to the emergency responders when they're dispatched. Using cellular phone towers and GPS phone location tracing will continue to save millions of lives in the future.