Teams User can call extensions on the PBX as they could from any other phone on the PBX as long as the Normalization Rule created in the Direct Routing setup is set as below. In the event there is a problem making extensions calls, please review these settings in the Microsoft Teams Admin portal.
If a Teams User dials another Teams User using their Teams registered number (i.e. 1001) or using Internal Teams dialing, the call will NOT be routed through the PBX. Often the Teams registered number (Phone Number in the User setup) is the same as the PBX extension. A solution is to append a 9 in front of the Teams registered number (i.e. 91001) to fake out Microsoft. Do this on the user profile in the ConnecttoTeams Enterprise Portal.
ConnecttoTeams adds a Normalization Rule (see Epilogue for everything added). Here is where you can go to review that or change it manually to settings that work better for your organization:
In the Microsoft Teams Admin portal under Voice>>Dial-plan, you can manually add in a Translation that clears away any appended digits (or to conform to the PBX dial plan you prefer).
Here is what we added to tell ms Teams to output dialed digits if the number is 7 or shorter:
match expression:^([0-9*#+]{1,7})$
translates to:
$1