Phone system between two M365 tenants

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Occasional Visitor

Greetings,

 

Consider the following scenario.

We have a company A with 10 users with E5 licenses. Phone system and direct routing are enabled.

We have a company B with 10 users with E5 licenses. Phone system and direct routing are enabled. Company A and company B have NO common infrastructure at all.

 

Now, let's say that company A and company B give external access on their tenants to each other.

Is it possible for a user on company A to call a user in company B via an extension number, in such a way that they were behind the same PBX (onnet call - no PSTN provider charges). 

 

Do you have any relevant official documentation for that?

 

Best regards!

1 Reply
For the dialing by extensions, you can add yourself some number normalizations between the two tenants, using dial plans. https://docs.microsoft.com/en-us/microsoftteams/what-are-dial-plans.

For the "no PSTN provider charges", that'll probably be a question for Microsoft support/billing to handle. I'm not sure I've ever seen any documentation that covers cross tenant calling.