Published: 8 October 2026 | By AOLC
If your business already runs on Microsoft 365, you are probably paying for a separate phone system alongside it — a hosted PBX, a SIP trunk, or a legacy on-premises switchboard. What many South African business owners do not realise is that Microsoft 365 already includes the collaboration side of the equation: Teams messaging, meetings, and video calls. For a relatively modest additional step, you can bring external phone calls into that same app and retire the separate phone system entirely.
That is what Microsoft Teams Calling — officially called Teams Phone — makes possible. This guide explains how it works, what you need, the three ways to connect it to the South African phone network, and what to watch out for before you make the switch.
Teams Calling is not part of your standard Microsoft 365 subscription. It requires a Teams Phone add-on licence — and then a choice of how you connect to the public phone network. Get those two steps right and your team makes and receives calls from within Teams, on any device, with no separate phone system to manage.
Microsoft Teams started as a collaboration and meetings platform. Teams Calling extends it to handle real phone calls — meaning your business number rings inside Teams, your team answers on a laptop, mobile, or Teams-certified desk phone, and clients on a normal landline or mobile can reach you without knowing you are on Teams at all.
The technical name is Teams Phone (previously called Phone System). It is Microsoft's cloud-hosted PBX engine, and it includes the features you would expect from a modern business phone system:
Teams Calling means one app for chat, meetings, file sharing, and phone calls — removing the context switch to a separate phone system your team may not use effectively.
Teams Phone on its own is a cloud PBX — it handles calls between your staff on Teams. To connect it to the public telephone network (so clients can call you from a normal phone number), you need to choose one of three PSTN connectivity options:
Microsoft provides your South African phone numbers and a bundle of minutes directly. You buy a Calling Plan licence per user and Microsoft handles everything: number porting, call routing, and the connection to the South African telephone network. This is the simplest option — no third-party supplier, no infrastructure to manage — and it suits businesses that want a single, predictable monthly bill from Microsoft. The trade-off is that call rates are fixed by Microsoft and may not always be the most cost-effective choice for high-volume outbound callers.
You connect your own SIP trunk — from an ICASA-licensed VoIP provider in South Africa — to Teams via a Session Border Controller (SBC). The SBC sits between your Teams tenant and your VoIP provider's network and handles the translation between Microsoft's signalling protocol and your carrier's SIP trunks. Direct Routing is the most flexible option: you choose your VoIP provider, negotiate your own call rates, and can port your existing numbers. It is also the most technically involved, which is why most South African businesses implementing it work with an IT partner like AOLC who manages the SBC and the carrier relationship on their behalf.
Tip
Before signing with any VoIP provider for Direct Routing, confirm their ICASA registration — either a full Individual ECS licence or an exempt-reseller registration from a licensed upstream carrier. A provider that cannot confirm either status operates outside South Africa's regulatory framework.
A participating carrier — such as MTN South Africa — joins Microsoft's Operator Connect programme and manages both the PSTN infrastructure and the SBC on your behalf. You assign numbers to users directly from the Teams admin centre, and the carrier handles the technical connection. This reduces the setup complexity of Direct Routing while still giving you the choice of a local South African carrier and their call rates. The number of Operator Connect partners in South Africa continues to grow, so this option is increasingly practical for businesses that want simplicity without committing to Microsoft's own Calling Plans.
Teams Calling licensing has a logical two-part structure. First, your users need a Microsoft 365 plan that includes Teams — Microsoft 365 Business Basic, Business Standard, Business Premium, or an equivalent enterprise plan all qualify. Then you add:
For businesses already on Microsoft 365 through a South African CSP partner like AOLC, adding Teams Phone is a line-item addition to your existing subscription — no new tenant, no migration, and no change to any of your other Microsoft 365 services. Contact your CSP partner for current per-user pricing, which varies by plan and whether you combine it with a Calling Plan.
Teams Calling requires no desk phone hardware. Every user can make and receive calls on a laptop, PC, or smartphone running Teams. You only need a physical phone if your team prefers one — and Teams-certified desk phones are available for those users.
One of the practical advantages of Teams Calling is that it is software-first. Your team makes and receives calls inside the Teams app on whatever device they already use — laptop, desktop, iOS, or Android. For most knowledge-worker roles, this means zero additional hardware spend.
Where physical phones still make sense:
Teams-certified desk phones run a version of Android with the Teams app baked in and appear in the Teams admin centre as managed devices, just like any other Teams endpoint. They are not traditional IP phones and require no separate PBX configuration — they register directly to your Microsoft 365 tenant.
This is the question every South African business owner asks, and it is a legitimate concern. Teams Calling is a cloud service — your phone system lives in Microsoft's datacentres, and your internet connection is the only path to it. During load shedding, if your office internet router loses power, so do your calls.
The solution is the same as for any VoIP-based phone system: a small UPS that keeps your router, network switch, and a few IP phones running through a typical two-to-four-hour outage. A UPS adequate for most small offices costs between R1,500 and R3,500. That is a once-off investment that eliminates the most common cause of Teams Calling disruption.
Beyond the UPS, Teams Calling has a built-in advantage over a traditional on-premises PBX: if your office is unreachable, your staff can still take calls from home or on their mobile using the Teams app on their personal device. Calls to your business number can be routed to a backup number (such as a mobile) or forwarded to voicemail automatically — configurable per user or per queue from the Teams admin centre, with no physical hardware to touch.
A traditional on-premises PBX goes completely dark when power fails. With Teams Calling, your staff can answer business calls on their mobile the moment load shedding starts — no forwarding setup required, no call centre overhead, no missed opportunities.
Teams Calling is an excellent fit for businesses that:
Teams Calling may not be the right fit if your business has high-volume outbound calling (where negotiating SIP trunk rates through Direct Routing becomes important to manage costs), very specific call-centre requirements that exceed what Teams queues offer, or staff who strongly prefer a traditional phone interface and are resistant to using a PC or mobile app for calls.
Before committing to Teams Calling, run through this practical checklist:
AOLC is a Microsoft CSP partner with hands-on experience deploying Teams Phone for South African businesses — including Direct Routing via ICASA-licensed carriers, number porting, and UPS protection planning. Contact us for a no-obligation assessment.
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