E-911
Enhanced 911
Wireless Enhanced 911 (E911) improves the effectiveness and reliability of emergency services by providing 911 dispatchers with additional information — primarily location — with 911 calls made from mobile phones.
With landline phones, if a 911 caller could not speak or effectively communicate their location, a 911 dispatcher could use the street address associated with that phone number to send help to the correct location. Before E911, no equivalent option was available to dispatchers for 911 calls made from wireless phones. E911 — a mandate from the FCC — corrected that.
Wireless carriers must report the telephone number of a wireless 911 caller and precise location information (within 50 to 300 meters in most cases) using technologies such as A-GPS and U-TDOA.
See: A-GPS
Newer FCC rules require the addition of altitude information (AKA "z-axis") so that dispatchers can approximate which floor the caller may be on in a tall building. This is typically accomplished using a barometer sensor to the phone, which is why most new phones for the US now have such a sensor.
The initial deployment of E911 in the early 2000s required the development and deployment of new technologies at local 911 dispatching centers (PSAPs), wireless networks, and on phones themselves.
Last updated Jun 6, 2024 by Rich Brome
Editor in Chief Rich became fascinated with cell phones in 1999, creating mobile web sites for phones with tiny black-and-white displays and obsessing over new phone models. Realizing a need for better info about phones, he started Phone Scoop in 2001, and has been helming the site ever since. Rich has spent two decades researching and covering every detail of the phone industry, traveling the world to tour factories, interview CEOs, and get every last spec and photo Phone Scoop readers have come to expect. As an industry veteran, Rich is a respected voice on phone technology of the past, present, and future.
