One number that follows the person, not the desk

Fixed Mobile Convergence

Without FMC, a user has two separate numbers — a work number in Teams and a personal mobile. When they're away from their desk, colleagues can't reach them on their work number, and they can't make work calls without revealing their personal number. Nobody in Teams knows if the person is on a mobile call. The work identity and the mobile identity are completely separate.

With FMC, the user's Teams number is also their mobile number — delivered through Call2Teams Mobile. Calls arrive in Teams on their mobile — whether they're at their desk or not. They make and receive calls from Teams, showing their business number, not their personal one. Colleagues see accurate presence. Business stays business.

Microsoft Teams phone enablement

PSTN-enabled Teams users surpassed 26 million and grew 30% in 2024/25 — but still represent only ~6% of the total Teams user base. The mobile layer is the next frontier.

Mobile innovation

4G VoWiFi, 5G, and eSIM/Dual SIM as standard have removed the technical barriers to native mobile business communications. The infrastructure is ready.

Business compliance and identity separation

Hybrid working has raised compliance and privacy requirements. Businesses need to keep personal and business identities separate on the same device — without restricting how employees work.

Work from anywhere

The expectation to be reachable on a work number — regardless of location or device — is now a baseline requirement, not a premium feature.

Value for you, your customers, and their users

For service providers selling Microsoft Teams, Call2Teams Mobile closes the gap between fixed and mobile — without requiring you to change your network infrastructure or add operational overhead. Connect your existing mobile network to the Converge platform via API, and your customers get one number that works everywhere. You get a mobile upsell that sits naturally on top of your existing Teams offering, strengthening your position in Microsoft deals and making your bundle harder to walk away from.

End customers maintain full control of business numbers — even when staff use personal devices. BYOD becomes straightforward, compliance requirements are easier to meet, and the employee experience improves without IT complexity.

End users — whether hybrid workers moving between office and home, or employees in the field all day — make and receive calls on their Teams number from anywhere. No second number. No separate app. Personal stays personal.

A SaaS bridge. No IMS. No app.

The architecture

Call2Teams Mobile connects Microsoft Teams to the mobile network through the Converge platform — mapping each Teams user identity to a dedicated mobile number. When a call comes in for the Teams extension, it routes through to the user's mobile. When the user makes a call from their mobile, it routes out through Teams — showing the business number, not the personal number.

The connection to the mobile operator uses standard SIP interfaces. No core IMS integration is required. This means faster deployment, less complexity, and significantly lower time-to-market compared to full IMS-based FMC implementations.

Frequently asked questions

Fixed Mobile Convergence (FMC) is a technology that connects a user's mobile phone to a business phone system — so their mobile device behaves like an extension on the office PBX. The user has a single work number that rings on both their desk phone and their mobile. Calls show the work number, not the personal number. Colleagues see accurate presence and line-state regardless of which device the person is using. Call2Teams Mobile delivers FMC natively inside Microsoft Teams — one number, one identity, across fixed and mobile. No separate app, no IMS integration.

No. Call2Teams Mobile connects to the mobile operator using a standard SIP interface — there is no requirement for core IMS integration. This is one of the key commercial advantages of the platform: it avoids the complexity, cost, and time associated with full IMS deployments, while still delivering native FMC behaviour inside Microsoft Teams. The platform maps each Teams user identity onto the user's mobile number through the Converge platform.

No. Call2Teams Mobile is a bridge between your existing mobile network and Microsoft Teams — it does not supply mobile numbers or SIM subscriptions. Service providers bring their own mobile network, and Call2Teams Mobile connects it to Teams via the Converge platform API.

Call2Teams Mobile

Built for service providers selling Microsoft Teams

One number that follows the person, not the desk