You must configure MS Teams to route emergency calls using emergency routing policies rather than the same voice routing policies MS Teams uses for normal calls.

The following is a summary of how MS Teams uses components for direct routing of emergency calls.

• Teams User > Emergency routing policy > PSTN usage > Voice routes > SBCs

1. The MS Teams user dials a number:

2. Emergency routing policy

   If the number matches one in the user's associated emergency routing policy, MS Teams uses that policy to route the call. If the number matches one in the policy's Emergency dial mask, MS Teams translated it to the Emergency dial string number. For example, if a user dials 911 or 999, MS Teams translates the number to 112.

3. PSTN usage

   MS Teams uses PSTN usage records to link a user's voice routing policy and the voice routes that the user's calls can use. The same PSTN usage must appear in each.

4. Voice routes

   MS Teams checks the translated number for a match in the available voice routes. MS Teams only checks voice routes with a PSTN usage that match a usage in the emergency routing policy.

5. SBC

   The matched voice route specifies the SBC or SBCs to use.

Routing Failure

In the above call flow, if direct routing fails at any point, MS Teams redirects the call to Microsoft Calling Plans if configured for the user. Otherwise, MS Teams drops the call.