# Emergency Services - DID Routing Description

The MiVoice Business Emergency DID Routing feature allows a PSAP emergency callback to be routed to an emergency caller's registration telephone DN or hot desk user DN.

To use this feature, you must contact your local carrier and purchase PSTN DID numbers that can also function as CESID numbers for the telephones on your private network. The purchased DID numbers must be assigned as CESID numbers to components within the premise (individual phones, network zones or multiple MiVoice Business systems). You must ensure that the purchased DID numbers (CESID) and related location information are registered with the local PSAP.

Emergency DID Routing requires that all participating hot desk users and registration telephone users are members of the same MiVoice Business cluster.

To use the Emergency DID Routing feature:

- The DID service must be enabled on the trunk service associated with the incoming PSTN gateway trunk in the Direct Inward Dialing Service form.

- The Emergency DID routing feature must be enabled in the Shared System Options form.

- If a customer implements one of the NG911 Vendor solutions to support Ray Baum Act compliance, the DID routing feature is no longer required and should be disabled.

If these conditions are met, and a hot desk user or registration telephone user places an emergency call from a private company network, then MiVoice Business automatically creates an Emergency DID entry in the Direct Inward Dialing Service form with the following information:

- DID number:
  CESID or DID number of the registration telephone of the emergency caller.

- PNI:
  Primary Node Identifier.

- Destination Number:
  The emergency caller’s DN.

- DID type:
  Emergency DID.

If an Emergency DID entry with a duplicate DID number exists, then that entry is replaced with the new Emergency DID entry.

Successful entries of Emergency DID records are captured by the MiVoice Business Audit Trail Logs.

If PSAP needs to call an emergency caller back, then PSAP will dial the emergency caller's CgPN (DID number). The incoming PSTN gateway trunk that has the DID service enabled will receive the PSAP’s callback and check the PSAP agent’s Called Party Number (CdPN) against the Standard and Emergency DID entries in the system. If both an Emergency DID entry and a Standard DID entry match exactly with the CdPN, then the Emergency DID entry will take precedence and the call is routed to the corresponding Destination Number.

The Emergency DID Routing feature is supported on:

- The following telephone sets:

- MiNET IP telephones

- ONS telephones

- SIP telephones

- MiNET Consoles

- Hot desk users logged into the supported telephone sets (listed above).

NOTE: If a customer implements one of the Vendor solutions, the DID routing feature is no longer required and must be disabled.

Related Topics

- Emergency Services - DID Routing Conditions

- Emergency Services - DID Routing Programming

- Emergency Services - DID Routing Maintenance