What Does a Business Need Before Enabling External Calling in Microsoft Teams?
A practical readiness checklist for enabling external PSTN calling in Microsoft Teams safely and reliably.
External calling in Microsoft Teams requires more than enabling a telephone icon. The business needs a suitable Teams Phone licence, a PSTN connectivity method, numbers, voice policies, network readiness, supported devices and an operational support plan.
Define users and call journeys
Identify who needs external calling, a DDI, queue membership, auto-attendant access or specialist features. Map main numbers, departments, opening hours, emergency arrangements and outbound caller identification.
Confirm licensing
Microsoft’s licensing varies by base subscription and function. Direct Routing users currently require Teams and Teams Phone, with other licences potentially needed for audio conferencing, contact-centre or advanced capabilities. Check the tenant rather than relying on an old quote.
Choose PSTN connectivity
Options can include Microsoft Calling Plans, Operator Connect, Teams Phone Mobile and Direct Routing. The choice affects carrier control, numbers, routing, SBC responsibility and support.
A managed Microsoft Teams Direct Routing service may suit businesses needing a chosen UK provider, existing numbers or more complex integration.
Prepare domains, identity and policies
Users must be correctly created, licensed and assigned voice policies. Direct Routing needs an appropriate verified domain for the SBC. Use role-based administration and protect privileged accounts.
Plan numbers and porting
Inventory main numbers, DDIs and ranges. Define assignments and call queues before porting. Validate losing-provider records and associated services. Do not cancel numbers before migration.
Assess the network
Review each office and remote-working pattern for bandwidth, latency, jitter, packet loss, Wi-Fi and firewall requirements. A suitable business broadband service is part of voice quality, but the LAN and endpoint still matter.
Select devices and headsets
Test Teams-certified headsets, room devices or phones with representative users. Consider reception, common areas, accessibility and home workers. Standardising approved equipment can simplify support.
Configure emergency calling and security
Document location and emergency-call handling for offices and remote users. Apply current Microsoft and provider guidance. Review recording, retention, access and privacy requirements before enabling features.
Test complete call flows
Use test numbers before porting. Verify inbound and outbound calls, caller ID, queues, auto attendants, transfers, voicemail, DTMF, emergency arrangements and failure routing. Capture examples for faults.
Agree ongoing ownership
Decide who manages Microsoft licences, Teams policies, the SBC, PSTN service, numbers, devices and network. Define joiner, mover and leaver procedures and an escalation path that spans supplier boundaries.
Readiness checklist
- Approved user and call-flow requirements.
- Validated licences and PSTN option.
- Number inventory and porting plan.
- Network and firewall assessment.
- Approved endpoints and support model.
- Test, migration and continuity plan.
Ask our UK team to review your Teams Phone readiness before assigning live business numbers.
