What is 9-1-1?
Nine-one-one is the number most people in the U.S. and some in International countries call to get help in a police, fire or medical emergency.  A 9-1-1 call goes over dedicated phone lines to the 9-1-1 public safety answering point closest to the caller.

What is Enhanced 9-1-1?
Enhanced 9-1-1, or E9-1-1, is a system which routes an emergency call to the 9-1-1 center closest to the caller, AND automatically displays the caller’s phone number and address. The 9-1-1 call taker will typically ask the caller to verify the information, which appears on his or her computer screen. On some occasions, phone number and location information may not be  available for 9-1-1 calls made from a cellular/wireless phone.