In a Direct Routing environment, how to send calls to SBC?

[pauljackson]

We have a Direct Routing deployment with an Audiocodes Mediant SBC handling PSTN calling. We have a legacy IP-PBX users in our environment, with a trunk established between the IP-PBX and the SBC. How can we enable calling from Teams to the IP-PBX (through the SBC)? When dialing a 3 or 4 digit extension, the call gets dropped by the Teams client before it can reach the SBC. One possible solution would be to add a normalization rule that pads the extension, ie +1 (555) 555-1234, where 1234 is the extension. Is there a better way to do this?

[#2]

Hi Paul,

The best way would be whenever a user dial's an extension is to normalize the call and route the call to the AudioCodes SBC using the Dial Plan configuration on Microsoft Teams Tenant.

Creating and Managing Dial Plans
https://docs.microsoft.com/en-us/microsoftteams/create-and-manage-dial-plans

With Regards,
Satish U

[#3]

Thanks Satish.

That document does not specify how to send calls to an SBC. It only covers the translation of numbers from one format to another.

[#4]

Paul,

Microsoft 365 will only process the E.164 format, In case we want to route the call from Teams to Third Party PBX we can route those using the Dial Plans to the SBC and define which SBC to be used with such Dialing pattern is configured.

With Regards,
Satish U

[#5]

Thanks Satish. This makes sense. The best way I can think to do this would be to pad the extension with extra digits to make it E.164 compatible, then strip those digits at the SBC. Is there any other way to accomplish this?