Page 226 of 258 Emergency Services configuration
IMPORTANT!
In Normal Mode, an IP Phone must have a Virtual Trunk available and configured between the main office and branch office in order to complete an emergency services call.
IMPORTANT!
Do not route ESA calls to a node that has no direct ESA trunks.
For SRG applications, Nortel recommends two alternative general methods to specify which digit string results in a call to emergency services:
•Use the Emergency Services Access (ESA) feature. This is the preferred method in North America, the Caribbean and Latin America (CALA), and in those countries that are members of the European Union (EU). ESA provides specific features and capabilities required by legislation in these jurisdictions.
•Use of a special dialing sequence, such as a Special Number (SPN) in the Network Alternate Route Selection (NARS) data block. This does not result in ESA features or capabilities.
The main office Call Server forwards emergency services calls to the SRG PSTN. Calls are redirected over a Virtual Trunk using the services of the NRS.
Emergency Services Access (ESA)
The ESA configuration specifies the digit sequence (a DN) that the user dials to start an emergency call, known as the Emergency Services Directory Number (ESDN). There can only be one ESA configuration per customer and thus only one ESDN per customer, which means that all telephones on the same network must be in the same numbering plan.
If the SRG and the main office do not use the same ESDN, the SRG must replace the incoming digits for the tandem ESA call from the main office with its own ESDN. Refer to Emergency Services Access: Description and Administration
