That's the first piece of information emergency dispatchers need to know to get help quickly to people like Alexa, age 12. When a fire broke out in her home, Alexa grabbed her dog and her cell phone, ran outside and got through right away to 911.
Fortunately, Alexa was able to give her address quickly and accurately. But if the caller can't give the address, the dispatchers have to rely exclusively on technology to locate the phone. And which kind of phone, cell or landline, is easier to locate?
"More effective is definitely calling from a landline because we get all the information on a screen and we have an exact location," Jeanette Cepin said.
Landlines - and Internet phone services called VoIP - are almost always located right away on call center screens. But pinpointing cell phones is more difficult.
"Emergency personnel locate a cell phone through its internal GPS or through cell tower signals. That's less precise than with a landline and could cost precious time."
Another issue when using a cell phone in an emergency - a weak signal can also cost you time.
"Our survey found a slightly higher percentage of cell-phone users had trouble getting through to 911 on the first try. But nearly all were able to get through with a little more effort," Paul Reynolds said.
So consumer reports' survey shows cell phones are pretty reliable. Nevertheless, consider keeping your landline if you don't get good cell-phone reception at home or you live in a remote or rural area where service can be spotty.
Also, a landline is better if you're concerned the caller may not be able to give an exact address in an emergency.
It's interesting to note, 60 percent of the 240 million calls made to 911 in the US comes from cell phones.
And consumer reports' survey shows, not surprisingly, that a big reason is people are calling from a car to report a road emergency.