Emergency Services configuration Page 227 of 258
With all sites using the same ESDN, a conflict occurs in the NRS. The conflict is resolved by using a unique prefix for each site that the main office adds as it routes the call. The suggested prefix is the ESN home location code of the SRG, or alternately, the Numbering Plan Area (NPA) code of the SRG if there is not more than one Call Server in the NPA. Virtually any unique string can be used as a prefix, because the call is sent to the NRS as an Special Number (SPN). In the NRS, SPNs have their own separate numbering plan.
The Automatic Number Identification (ANI) data sent to the Public Safety Answering Point (PSAP) identifies the location of the caller. In some constituencies, legislation requires one DID per fixed number of square feet, so the physical location of the emergency can be approximated based on the telephone number delivered to the PSAP. The ESA feature has a comprehensive scheme that can be used to convert an extension into an appropriate DID.
If the branch office is relatively small, it can be easier to use a single DID number for the branch office. For more information on this command, refer to Software Input/Output: Maintenance
Routing Emergency Services Access (ESA) calls
IMPORTANT!
Do not route ESA calls to a node that has no direct ESA trunks.
Ideally, route ESA calls directly over Central Office (CO) trunks to the Public Safety Answering Point (PSAP). In those cases where this routing is not possible, do not route ESA calls to nodes that have no direct ESA trunks.
Main Office Configuration for Survivable Remote Gateway 50 Configuration Guide
