Definition:
This is an introduction not an indepth analysis of 911. According to the National Emergency Number Association, the main characteristic of E-911 is the capability of the E-911 Tandem CO-Central Office to selectively route a 911 call originated from any station (telephone number) in the E-911 service area to the correct primary (controlling) PSAP-Public Service Answering Point designated to serve the originating station's location.