A caller who needs emergency assistance dials one of the following Universal Emergency Numbers (UENs):
The system routes the call through a local central office (CO), through an emergency tandem office, to the appropriate public safety answer point (PSAP). The PSAP answers the call.
A tandem office can route the call to a PSAP in surrounding areas. In the United States, a tandem office can route the call to nearby area codes. If the PSAP that receives the call is the incorrect PSAP to handle the emergency, the PSAP transfers the call to the correct PSAP. Transfers can only occur between geographically adjacent or nearby PSAPs.
Each PSAP usually covers one city, or one rural county or community. At the PSAP, emergency operators determine the nature of the emergency, and contact the appropriate response agency. In the United States, a PSAP is usually responsible for an area that covers several independent police and fire departments.
With E911, the system sends the call and the Calling Party Number (CPN) over Centralized Automatic Message Accounting (CAMA) trunks. The system can also send the call and the CPN through the calling number information element (IE) over Integrated Services Digital Network (ISDN) trunks.
To learn how CAMA and ISDN trunks translate an extension to the PSAP, see Administering Avaya Aura® Communication Manager.
The public emergency system maintains a database that stores location and background information to help public safety agencies respond quickly with the appropriate assistance. The PSAP uses the CPN or the Caller Emergency Service Identification (CESID) number to look up the street address of the caller. The PSAP uses an Automatic Location Information (ALI) database. The ALI database is usually owned and managed by local exchange carriers (LEC). Instead of a LEC, customers can also contract with a third party to update the ALI database for them.
The E911 feature does not provide PSAP with the location of the person who placed the emergency call if the call came from a telephone that is on:
A system that is not equipped with CAMA, ISDN trunks, or SIP trunks
An adjunct computer system that is associated with CAMA, ISDN trunks, or SIP trunks
Instead, the E911 system identifies only the location of the trunk termination.
To solve this problem, you can report the emergency location extension as the CPN. After someone moves a telephone, you can manually correlate the CPN with the new telephone location. You can also purchase an adjunct that performs this correlation and update for you. You do not have to update the ALI database for the public switched telephone network (PSTN) after each telephone move.
The E911 feature transmits the extension of a direct inward dialing (DID) telephone that is associated with the calling party. The E911 feature transmits either:
CESID over CAMA trunks
CPN over ISDN trunks
The calling party might be at or near a telephone on a remote port network. The calling party might also be at a remote location that is served by an off-premises telephone.
Important:
If you use the digit 9 on the Dialplan Analysis Table screen as the ARS access code, also administer the dial string 11 as either an emer or alrt number. That way, when a user dials 911, the digit 9 provides an outside line, and the digits 11 indicate an emergency or crisis alert call.
For Avaya IP Softphone, if the Remote Softphone Emergency Calls field on the Station screen is set to as-on-local, the system processes information based on certain criteria. For more information on what the system does when the Remote Softphone Emergency Calls field is set to as-on-local, see Administering Avaya Aura® Communication Manager.
