Before You Call 911 on a Cell Phone

There's a difference between calling 911 on a mobile phone and calling from a landline. The difference has to do with how the calls are routed and how they're tracked. If you know what to expect, you're more likely to get the help you need when you need it.

When you call 911 from a landline in most parts of the country, emergency responders can find you—even if you don't know where you are or you can't speak. That's because calling 911 from a traditional landline (a telephone connected to the lines on the poles) makes a computer in the dispatch center show the number and address of the phone you're using.

It's called the ANI/ALI (automatic number identification/automatic location identification) and it's standard equipment in any Public Service Answering Point (PSAP), which is colloquially known as the 911 center.

When you make a 911 call on a cell phone, you are sending signals through the air. The tower that picks up your phone's signal may be near or not. That's not enough information for the dispatcher to find you. It's like playing "Marco Polo" in the pool--blindfolded with just sound to guide you.

The Federal Communications Commission requires that all wireless carriers must be able to pinpoint your location for the 911 dispatchers, but the rule is coming in phases and there are plenty of exceptions.

When you call 911 from a mobile phone, the call often lands in a regional center. A call-taker in a far-away city or county may answer. To get help to you, there are two pieces of information the call-taker needs to know immediately:

1. Tell the call-taker which city you're calling from.
2. Tell the call-taker what type of emergency you have (police, fire or ambulance).

Different emergency services use different dispatch centers. With the right information, the call-taker will transfer you to the right center.

Wireless carriers are required to complete 911 calls, even when the phone is not activated. Any phone that turns on and can receive a signal is capable of making a 911 call.

Important: if the phone you're using isn't activated, there isn't a phone number assigned to it. That means if you're disconnected from the dispatch center, you must call 911 back. They will not have a way to call you.

Professional call-takers are trained to get information from you. They're staring at a computer screen that has all the relevant questions. Listen carefully, and answer as concisely as possible.

Remember, responders can only respond if they know where they're going. Make sure you get the location as detailed as possible.

The National Emergency Number Association (NENA) reports that in 2011, more than 31% of US households were only using a wireless phone. In 2011, there were 146 million 911 calls from mobile phones.