Considerations for Enhanced 911

Last Updated : Oct 30, 2012 |

This section provides information about how the Enhanced 911 feature behaves in certain circumstances. Use this information to ensure that you receive the maximum benefits of Enhanced 911 under all conditions.

The following considerations apply to Enhanced 911:

  • The Enhanced E911 feature only applies to emergency calls that go over CAMA, ISDN and SIP trunks.

  • You must provide several call appearances on the last telephone in both the coverage path and the telephone hunting path of the Emergency Location Extension.

  • Do not include voice mail, automated attendant, or announcement extensions for Emergency Location Extensions.

The following two consideration scenarios apply to a Survivable Remote Server (Local Survivable Processor), and to backup duplex servers. These considerations apply if the spare processor is an asynchronous transfer mode wide area network (ATM WAN), or is on a survivable remote expansion port network (EPN).

  • Sending the correct ELIN to the PSAP

    Once each day, the Survivable Remote Server copies administration translations from its primary server. The system never copies translations from the Survivable Remote Server to the primary server. IP telephones can stay under the control of a Survivable Remote Server for 6 days, 10 days, or indefinitely. The length of time depends on what version of software you are running.

    If someone notifies you that an IP extension moved, update the ALI database with the physical location of the IP extension. Also change the Emergency Location Extension field on the IP Address Mapping screen to match the new subnetwork of the IP extension. You can also purchase an adjunct that performs this correlation and update for you.

    If the telephone registers with the Survivable Remote Server before the system copies the translations from the main server, the Emergency Location Extension field is still set to the old value. If the user dials 911, emergency response personnel might go to a different location for the caller instead of to the exact location.

    Never update translations directly on the Survivable Remote Server.

The following considerations apply to the Crisis Alert capability:

  • The Automatic Number Identification (ANI) that the system sends to the CO might not be the same extension as the telephone that the person used to dial the emergency. If the call is disconnected and the public service person call back, the public service person calls the ANI. The public service person might not reach the caller.

    If a telephone has a crss-alert button assigned, the return call is answered by someone who was notified of the extension that made the emergency call. That person can then forward the return call from the public service person to the extension from which the emergency call was placed.

  • Only one crss-alert button can appear on an attendant console or a digital telephone.

  • Attendant consoles or digital telephones without a crss-alert button do not receive emergency notification.