Microsoft Teams Phone needs a PSTN connection to call external numbers. There are three main options, and many multinational organisations use more than one.
Calling Plans
Microsoft acts as the carrier. It is the simplest to deploy, with no SBC, but has limited country coverage and the least control over routing and number porting.
Operator Connect
A participating carrier connects its network directly to Microsoft and manages the SBC infrastructure. You assign numbers in the Teams admin center. It offers a good balance of simplicity and carrier choice.
Direct Routing
You connect your own certified SBC, such as Cisco CUBE, to Microsoft's SIP proxies. This is maximum control: any carrier, existing PBX and CUCM integration, media bypass, Location-Based Routing and complex dial plans. It also means you own the SBC operations.
How to choose
- Need to integrate with CUCM, analogue devices or contact centres? Direct Routing.
- Want carrier-grade service without running SBCs? Operator Connect, where available.
- Small sites in supported countries with simple needs? Calling Plans.
Go deeper: our Teams Direct Routing training covers this topic with hands-on labs.