Microsoft Teams Direct Routing for Australian Business

What is Microsoft Teams Direct Routing?

Microsoft Teams Direct Routing connects your Teams tenant to the Public Switched Telephone Network (PSTN) — the global telephone network — so that your team can make and receive real phone calls without leaving the Teams app. Instead of subscribing to a Microsoft Calling Plan, Direct Routing lets you bring your own voice provider and PSTN numbers. The result is full outbound and inbound calling from the Teams desktop client, mobile app, or a certified Teams handset, using your existing Microsoft 365 licences.

Simtex provides a managed Direct Routing service for Australian businesses. We host and operate Microsoft-certified Session Border Controllers (SBCs) in geo-redundant Australian data centres, handle the SBC configuration, and assign Australian phone numbers directly to your Teams users. You connect through us — no hardware to procure, no SBC to manage on your end.

A SIP trunk built for Teams

Under the hood, Direct Routing works by establishing a SIP (Session Initiation Protocol) trunk between your Teams environment and Simtex's infrastructure. When a Teams user dials an external number, the call passes from Microsoft's cloud to our SBCs over an encrypted TLS 1.2 signalling path, then on to the PSTN. Media travels directly via SRTP-encrypted streams, with media bypass and media optimisation supported to minimise latency.

This architecture is why Direct Routing is often preferred over Microsoft Calling Plans for Australian organisations. All voice infrastructure remains on Australian soil — our primary data centres are in Perth and Sydney — which satisfies data sovereignty requirements and keeps latency low for local calls. Pricing is also structured differently: you pay per simultaneous call channel (concurrent line), not per user, so a 50-person organisation that never has more than ten people on the phone simultaneously pays for ten channels, not fifty licences.

Why not just use a Microsoft Calling Plan?

Microsoft Calling Plans are per-user, per-month subscriptions sold through Microsoft. They are convenient for small deployments but become expensive at scale, are not always available with full feature parity in Australia, and offer less control over numbering, routing, and call recording. Direct Routing gives your business the flexibility to choose a local provider, port your existing Australian numbers, and configure routing rules to suit your operations — including failover routing and emergency services (000) from a registered business address.

How Microsoft Teams Direct Routing works

The Simtex Direct Routing service sits between Microsoft's cloud and the Australian telephone network. Here is what happens when your setup is live:

• Your Teams environment — Users make and receive calls directly inside Microsoft Teams on any device: the Teams desktop client on Windows or Mac, the Teams mobile app on iOS or Android (the so-called Teams softphone), or a Microsoft-certified desk phone. No separate calling app is needed.
• Microsoft's cloud — Teams routes the call to the Direct Routing interface. Microsoft's cloud handles all the Teams-side signalling; your Call Analytics data in the Teams Admin Centre is retained in full.
• Simtex SBCs — Our Microsoft-certified Session Border Controllers (SBCs) receive the call, handle codec negotiation, enforce TLS 1.2 signalling and SRTP media encryption, and route the call to the correct PSTN destination. Our SBCs are geo-redundant across Australia; if one site is unreachable, failover is automatic.
• PSTN termination — The call leaves our infrastructure and reaches any landline or mobile number in Australia or internationally at per-minute rates.

What you need on the Microsoft side

To use Teams Direct Routing, each user who will make or receive external calls needs a Teams Phone Standard licence (or a Microsoft 365 plan that includes Teams Phone, such as E5). This is a Microsoft licence — Simtex provides the PSTN trunk on top of it. If you are unsure which licences apply to your Microsoft 365 subscription, our licence requirements guide covers the options in detail.

Outbound caller ID is fully supported. You can present your main business number for all outgoing calls or assign a personal DID (Direct Inward Dial number, in E.164 format) to individual users. Full call recording options are also available.