Warning: When Dialing 911 on a Cell Phone or VoIP Service, Location Tracking is Limited

By Chris Hoffman on December 19th, 2014

Mobile Phone In Pocket With Emergency Number 911. Focus On Screen

We’ve all seen it in movies: Someone’s in an emergency situation, so they dial 911 on a landline phone and run off. The police then rush to their location. This location tracking doesn’t work as well with cell phones and VoIP services.

As we move from landline phone services to mobile phones and VoIP services, it’s important to realize the limitations. In an emergency situation, you should try to stay on the line long enough to give the operator your precise location.

How 911’s Landline Location Tracking Works

Thanks to something called “Enhanced 9-1-1” — used in North America — your location is recorded when you place a call to 911 on a landline telephone. The “public-safety answering point” that receives the call then uses your phone number to look up your location in a database.

This generally works very well, and very quickly. As we’re talking about landline phones here, each landline phone has a specific physical address associated with it — for example, a house address or apartment building address and apartment number. Even this system can occasionally fail if the phone number isn’t passed along properly or the information in the database isn’t correct, in which case the 911 operator would have to ask you for your location.

It’s always a good idea to stay on the line to provide your location and any other relevant information!

Vintage phone on green background. Hotline support concept. 3d

Cellular Phones and VoIP Services Challenge This

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Cellular phones aren’t linked to a single physical location — they’re always moving around. However, their locations can be tracked with triangulation (comparing the relative signal strength between three cellular towers) and their GPS hardware.

VoIP services are even tougher to track, as the calls are sent over the Internet and simply come from an IP address with no cell tower information or GPS data to rely on. Both of these new technologies pose challenges.

How Much Location Data is Sent From Your Smartphone

But some location data is still sent! In 1996, the US FCC began requiring wireless carriers to transmit location data from 911 calls placed from mobile phones on their networks. The requirements ramped up from simply sending the location of the cellular tower the call was placed on to providing the location of the calling cell phone itself.

Cellular carriers may get this data from cellular triangulation, or the phone’s GPS chip itself. However, there’s no recognition that they can get the data from the Wi-Fi data that modern phones use to track our locations even more precisely, especially indoors.

Carriers are required to provide a phone’s location “within 50 to 300 meters.” That’s 164 feet to 984 feet. It goes without saying that this is fairly imprecise, especially if you’re in a dense, urban area with lots of buildings and people. And this is for outdoor locations. There’s also no way to pinpoint you on a specific floor of an indoor area.

So, while this is better than nothing, it’s not something you want to rely on in an emergency situation. The FCC wants to tighten location requirements for cell phone 911 calls, but this won’t happen until 2019 at the absolute earliest.

Transmitter

VoIP Location Reporting

VoIP services are even tougher to deal with here. When you dial 911 from Skype or the phone call feature in Gmail, what happens? Often, nothing happens. To avoid liability, many services — like Skype and Gmail — won’t allow you to call 911 at all. They make it clear they’re not a replacement for traditional phone servics in emergency situations. That’s something to bear in mind — you can’t use Skype or Gmail to place a 911 call in an emergency, even though they can be a convenient replacement for traditional phone service in many other situations.

Some VoIP services do allow you to call 911, however — especially ones designed to replace a traditional landline phone. You register your home address with these services and they’ll provide it to a 911 service in case of emergencies. Be sure to look into whether your VoIp provider supports 911 and ensure you know how it will work in an emergency.

Other forms of VoIP — for example, a large office building that uses voice-over-IP features — can have physical address data assigned to each VoIP endpoint. It would be possible for a corporation using a VoIP network to have the exact floor and office number of each VoIP phone call tracked in a location database that could be provided to 911 services, for example.

voip phone


By the way, you also probably can’t contact 911 with a text message. Text-to-911 service is still very rare and only available in limited areas. This should become widespread at some point in the future, however. For now — like with location tracking — it’s important to bear the limitations in mind. That knowledge just might help you if you ever need to contact 911 in an emergency situation.

Image Credit: King Huang on Flickr

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 12/19/14
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