Microsoft Teams Shared Space vs SIP in Australia: when shared phones and reception desks make Teams the expensive voice option

01What changed in April 2026, and what did not

The first thing to clear up is scope. Microsoft states that the Teams Shared Space licence applies to shared devices including Teams Phone devices deployed in common areas, Teams panels, desk docks and Android mobile phones as shared devices. The same page says the licence was called Teams Shared Devices before April 2026. So this is not just a cosmetic wording issue for buyers doing a fresh telephony review, it is the current licensing frame for common-area phones.

There is also a practical distinction between Shared Space and Shared Space - Single Space. Microsoft says a Shared Space licence can be used for one Teams device, or for four bookable desks or BYOD rooms, while Single Space licences are the zero-dollar per-space licences for desks and BYOD rooms. For voice buyers, the key point is simple: a common-area Teams handset consumes a paid Shared Space licence per device.

What did not change is that Shared Space is not a substitute for the rest of the voice design. If you need auto attendants, call queues or other voice application objects, Microsoft still requires resource accounts, each with a free Teams Phone Resource Account licence. Microsoft also states that if those queues or auto attendants transfer calls externally, use callback, or present outbound caller ID on behalf of a queue, the resource account needs extra PSTN capability, such as pay-as-you-go, communications credits, a Direct Routing policy, or Operator Connect assignment depending on the setup.

• Shared Space is the current common-area device licence from April 2026 onward
• Each common-area Teams phone needs its own paid Shared Space licence
• Resource accounts for call queues and auto attendants are still separate
• Outbound PSTN behaviour from queues can trigger extra licensing or routing requirements

02Why reception and common-area patterns distort the Teams cost model

A standard Teams Phone proposal often looks acceptable because user licensing is spread across staff who already live inside Microsoft 365. Reception and common-area telephony break that pattern. A reception desk usually needs queue handling, transfer logic, business hours logic, hunt groups, shared numbers and stable desk-phone behaviour. Common-area handsets often need only inbound and outbound PSTN calling, not full collaboration features.

Microsoft does support common-area phones. Its setup guidance says common area phones are not directly associated with an individual user and are instead signed in with a resource account tied to a Teams Shared Space licence. That is technically clean, but economically it means every hallway, warehouse, reception overflow or break-glass handset becomes a monthly licensed endpoint.

The problem is not just licence count. It is stacking. A reception design may need queue resource accounts, service numbers, Shared Space licences on desk devices, named-user Teams Phone licences for reception staff, plus PSTN connectivity through Operator Connect or Direct Routing. On paper, none of those pieces is individually surprising. In aggregate, they can make Teams expensive for front-of-house telephony compared with a SIP trunk feeding a PBX or even a small hosted PBX focused on voice only.

If you are already redesigning Microsoft licensing more broadly, this is similar to the pattern discussed in Australia Microsoft 365 renewals in 2026: should room mailboxes, scanners and no-reply accounts leave first. Shared or service-style identities change the economics faster than named users do.

• Shared handsets create per-device recurring cost
• Reception often adds queue and transfer complexity
• Front-of-house users may still need separate named-user telephony licences
• PSTN routing and number presentation can add another layer of cost and admin

03Where Teams Phone still makes sense

Teams is still a good fit when the reception or common-area device is part of a broader Microsoft-centric calling model. Microsoft positions Teams Phone as a cloud phone system with PSTN connectivity options from Microsoft or third-party providers, collaborative calling, shared calling and a single admin console. If your receptionists are already heavy Teams users, your supervisors need presence, call history, consult transfer and queue handling inside the same client, and you are standardising on Teams-certified hardware, keeping voice inside Teams can reduce tool sprawl.

It is also stronger when the number of shared endpoints is small. A single reception desk plus one or two common-area handsets is usually not enough to justify running or maintaining separate PBX infrastructure. In that case, the operational simplicity of staying with Teams often beats the theoretical savings of a separate SIP-led stack.

There is also a governance argument. Some IT teams prefer one policy surface for identity, device access and admin controls. If that matters, technology consulting and governance and compliance support should be part of the review, because the cheapest telephony line item is not always the cheapest operating model.

• Few shared phones
• Receptionists are already Teams-first workers
• Presence and integrated transfer behaviour matter
• You want one Microsoft-led admin model

04Where SIP or PBX-led voice starts to win in Australia

SIP or PBX-led voice tends to win when the estate has many shared endpoints and relatively few actual call-handling users. In that model, you pay for call capacity, numbers and PBX capability rather than licensing every shared device as a Microsoft endpoint.

Australian SIP pricing illustrates why. Public pricing from Simtex starts at A$4.99 per channel per month for pay-as-you-go SIP trunks, with unlimited local and national calling from A$14.95 per channel per month. 2talk publishes cloud and calling pricing with plans from A$0 to A$320 per month, local and national rates from 3c per minute and mobile bundles from 6.5c per minute equivalent on bundled plans. These are not universal benchmarks, but they show the cost unit difference: SIP usually prices around channels, numbers and call traffic, while Teams common-area voice prices around licensed endpoints plus the surrounding Teams voice structure.

That matters in practical Australian layouts. A school campus, warehouse, aged-care site, retail chain or manufacturing facility may have a large number of handsets but only a handful of concurrent calls. In that environment, five to ten SIP channels and a PBX can support many phones, whereas Teams Shared Space licensing scales with each handset.

This does not mean SIP is automatically cheaper. You still carry PBX hosting, support, failover, handset provisioning and security overhead. But if your estate is endpoint-heavy and concurrency-light, it is usually the first model worth costing seriously. If you are migrating from old telephony infrastructure, Legacy PBX to SIP trunk migration is the internal primer to read before you start numbers work.

• Many shared handsets, few concurrent calls
• Reception function is voice-heavy, not collaboration-heavy
• You want to size on call channels, not device licences
• Desk phones are mainly there for availability and coverage

05The hidden cost items buyers miss

The wrong comparison is Teams licence versus SIP channel. The right comparison is operating model versus operating model. For Teams, include Shared Space device licences, named-user Teams Phone licences where needed, resource accounts, service numbers, PSTN connectivity design, handset certification and queue requirements. Microsoft is explicit that resource accounts are required for auto attendants and call queues, and that resource account licensing is free but still mandatory.

For SIP, include PBX software or hosted PBX fees, SIP channels, DIDs, 1300 numbers, handset procurement, SBC requirements where relevant, security hardening, monitoring and support. Independent Australian market guides note that SIP pricing is shaped by per-channel fees, DID hosting, call bundles, emergency calling fees and whether you self-host or use hosted PBX. Even if you do not rely on those guides for final procurement, they are useful for building a complete checklist.

The biggest effort cost is usually cutover complexity. Teams looks simpler when your tenant is already mature. SIP looks simpler when your organisation already knows PBX operations. The answer often depends less on headline price and more on which operational capability you already own. If not much of that capability exists, a partner that can handle telephony infrastructure, cloud infrastructure and managed support matters more than saving a few dollars on a licence line.

• Do not compare a Teams device licence with a single SIP channel in isolation
• Model all queue, number, handset and support components
• Operational familiarity changes the real cost more than list price often does
• Migration and support overhead can wipe out small paper savings

06Questions to ask before you commit

Start with concurrency, not handset count. How many simultaneous external calls actually occur at reception peak, site peak and failure peak. Then ask which charges scale by device, which by user, which by queue and which by concurrent call path.

For Teams vendors, ask them to separate the cost of common-area phones under Shared Space licensing, named reception users, PSTN connectivity method, and any outbound queue features that trigger additional requirements under Microsoft's voice applications licensing rules. Ask them specifically whether every shared phone really needs to be a Teams-native endpoint.

For SIP or PBX vendors, ask how they handle emergency calling, internet outage behaviour, handset survivability, number porting, SBC requirements, fraud controls, and support boundaries between carrier, PBX and site network. Ask for a cutover plan that names exactly who owns numbers, routing, call flow testing and rollback.

If your organisation is already comparing Teams-based calling choices, the adjacent posts Australia Teams Phone with shared reception and call queues: when the PSTN design makes per-user licensing the wrong model and Teams Phone in Australia when Calling Plans are not the fit: Operator Connect, Direct Routing or leave Teams for voice? help frame the routing side of the decision.

• What scales by device, user, queue and call path
• What happens to reception during WAN failure
• How external transfer, callback and caller ID are licensed or routed
• Who owns number porting and rollback
• What support boundary exists between carrier, platform and your network team

07A workable rule for Australian IT directors

Use Teams Phone when shared phones are few, reception staff are already Teams-centric, and the operational value of one Microsoft environment outweighs the extra per-device cost. Start costing SIP or PBX-led voice as soon as shared endpoints become numerous, call concurrency stays low, or reception behaves more like a traditional operator function than a collaboration workflow.

The April 2026 Shared Space change did not make Teams wrong. It made the common-area cost line easier to see. That is useful, because it exposes where Teams is being asked to solve a voice pattern that a SIP model may price more naturally.

If you need a neutral design review, SyncTrix can help scope the telephony architecture and migration options. The right answer is usually not Teams everywhere or PBX everywhere. It is matching the commercial model to the actual way your reception desks and shared phones are used.