Contents
Executive summary
Enterprise voice environments have grown increasingly complex. Many organisations now operate a mix of on-premises PBXs, cloud platforms, and multiple calling providers across regions. Even those that are fully cloud-based often run several voice solutions in parallel. What began as flexibility has, over time, created operational overhead, inconsistent user experiences, and rising risk.
This white paper examines why consolidation is difficult, and why hesitation around moving to a single platform or provider is understandable. Concerns about resilience, local requirements, lock-in, and migration risk are common among both business leaders and technical managers.
It then outlines how Microsoft Teams Phone provides a practical foundation for consolidating enterprise voice. By bringing telephony into a platform many organisations already use for collaboration, Teams Phone simplifies user experience and centralises management, while still supporting enterprise-grade requirements.
The paper explains how PSTN connectivity works within Teams Phone, including Operator Connect, customer-managed Direct Routing, and Direct Routing as a service. It shows how provider-managed models, such as Operator Connect and Direct Routing as a service, reduce operational burden while retaining control and flexibility.
Finally, it highlights how LoopUp enables organisations to adopt Teams Phone at global scale. By managing PSTN connectivity, resilience, and ongoing service operations, LoopUp helps enterprises simplify fragmented voice estates without sacrificing reliability or local fit.
The conclusion is clear. Consolidation does not have to mean loss of control. With the right platform and the right calling provider, organisations can reduce complexity, lower risk, and build a voice environment that supports how modern enterprises operate.
Consolidating enterprise voice without losing control
Why enterprise voice estates become complex
Most organisations did not set out to build a complicated voice environment. Complexity crept in over time, driven by growth, mergers, geography, and the steady evolution of telephony technology.
Some enterprises still run entirely on on-premises PBXs that have been carefully maintained for years. Others sit in the middle, with a blend of legacy PBXs, hosted voice platforms, and collaboration tools layered on top. Increasingly, many are fully cloud-based but far from simple. They may run different voice platforms in different regions, use multiple calling providers, or maintain parallel solutions for specific use cases.
At a glance, this diversity can look like flexibility. In practice, it often creates operational drag. Multiple contracts, inconsistent user experiences, uneven call quality, and fragmented support models all add up. For business leaders, voice becomes a hidden tax on time and budget. For technical managers, it becomes a constant exercise in coordination and compromise.
Against this backdrop, platforms like Microsoft Teams Phone promise consolidation. Yet hesitation remains. Moving to a single platform, or a single calling provider, can feel like giving something up rather than gaining control.
The hesitation behind consolidation
When organisations resist consolidation, the reasons are usually rational. One concern is resilience. A distributed estate with several providers can appear safer than relying on one. If one platform fails, surely another can take over.
Another concern is local fit. Different countries have different regulatory requirements, numbering rules, and calling patterns. A global standard can sound good in theory but risky in execution.
There is also fear of lock-in. Once voice is tied closely to a collaboration platform, or to a single provider, it can feel harder to change course later. For teams that have spent years building optionality into their voice strategy, this is not a small emotional or technical shift.
Finally, there is simple disruption risk. Voice is business critical. Any migration that affects calling touches customer experience, internal productivity, and in some cases safety or compliance. Even when the destination looks better, the journey can feel daunting.
These concerns deserve to be taken seriously. The question is not whether consolidation is risk-free. It is whether the risks of maintaining fragmented voice estates are now greater.
What Microsoft Teams Phone actually is
Microsoft Teams Phone is the cloud telephony capability built into Microsoft Teams. It enables users to make and receive external telephone calls directly from the Teams interface, using the public switched telephone network, or PSTN.
PSTN is the global network that carries traditional telephone calls. Even in a cloud-first world, PSTN connectivity remains essential for reaching customers, partners, and external numbers.
Teams Phone replaces or supplements traditional PBXs by moving call control, routing, and user management into the Microsoft 365 environment. Users keep one client, Teams, for meetings, messaging, and voice. Administrators manage users, numbers, and policies through familiar Microsoft tools.
What Teams Phone does not do by itself is provide PSTN connectivity. That connection is delivered through specific models that determine how calls enter and leave Microsoft’s cloud.
How PSTN connectivity works in Teams Phone
There are several primary ways enterprises connect Teams Phone to the PSTN.
Operator Connect allows organisations to use approved calling providers that integrate directly with Microsoft. The provider manages the PSTN connection, numbers, and call routing, while Teams remains the user experience and control layer.
Direct Routing enables organisations to connect Teams Phone to SBCs, or Session Border Controllers, which then connect to one or more carriers. In a customer-managed model, the organisation owns and operates this infrastructure itself. This offers flexibility and reuse of existing assets but also places responsibility for design, resilience, and ongoing management on internal teams or specialist partners.
Direct Routing as a service is an alternative approach within the same technical framework. Here, the calling provider operates and manages the SBCs and carrier connectivity on the customer’s behalf.
From the customer perspective, this is operationally much closer to Operator Connect. PSTN connectivity, resilience, and service management sit with the provider, while Teams Phone remains the user experience and control layer.
Microsoft also offers Calling Plans in some markets, where Microsoft acts as the calling provider. Availability varies by country and may not meet the needs of global enterprises.
Choosing between these models is not purely technical. It reflects how much control an organisation wants to retain, how globally consistent it needs to be, and how much operational overhead it is willing to carry.
The real trade-offs of fragmented voice estates
Before looking at consolidation, it is worth being clear about the costs of staying as you are.
Fragmented voice estates often mean fragmented accountability. When call quality drops, or outages occur, responsibility can be hard to pin down. Collaboration vendors, carriers, and local providers may all be involved, slowing resolution.
User experience is another hidden cost. Employees moving between regions or roles encounter different calling behaviours, features, and limitations. Training and support become more complex, and adoption of collaboration tools can stall.
From a financial perspective, multiple platforms and providers drive duplicated spend. Licences overlap. Contracts renew on different cycles. Volume discounts are harder to achieve. Costs may be acceptable locally but inefficient globally.
Security and compliance add further pressure. Ensuring consistent call recording, data handling, and lawful intercept capabilities across disparate systems is challenging, especially as regulations evolve.
Over time, what once felt like flexibility can start to look like technical debt.
What consolidation actually changes
Consolidating onto Microsoft Teams Phone does not mean collapsing all decision-making into a single, inflexible model. It means standardising the user and management layer, while making deliberate choices about connectivity underneath.
For end users, the impact is straightforward. One application for internal and external communication. One number identity. Fewer handoffs between tools.
For IT teams, consolidation simplifies policy, security, and lifecycle management. Changes can be rolled out globally without rebuilding solutions in each location.
The remaining question is how to consolidate PSTN connectivity without reintroducing risk or losing local capability. This is where the choice of calling provider matters.
Where LoopUp fits
LoopUp provides PSTN connectivity for Microsoft Teams Phone, using the Operator Connect and Direct Routing models, depending on customer requirements. The goal is not to abstract away complexity by ignoring it, but to manage it centrally and transparently.
For organisations concerned about resilience, LoopUp designs voice services with redundancy and geographic diversity. This addresses the fear that one provider equals one point of failure, without requiring customers to manage multiple carriers themselves.
For global enterprises, LoopUp focuses on consistent service across countries. That includes number management, call quality monitoring, and regulatory alignment, delivered through a single operational relationship rather than dozens of local ones.
For teams wary of lock-in, using Teams Phone with a provider like LoopUp separates collaboration choice from carrier operations. Teams remains the user platform, while PSTN services can evolve independently if requirements change.
Addressing common concerns head-on
Will we lose local flexibility?
Consolidation does not mean ignoring local needs. It means meeting them within a common framework.
Local numbers, dialing rules, and compliance requirements can still be addressed, but without building bespoke platforms in each region.
Is call quality good enough?
Call quality in cloud telephony depends on network design, monitoring, and carrier integration.
A managed calling provider focused on Teams Phone can often deliver more consistent quality than a patchwork of local solutions, precisely because performance is measured and managed end to end.
What about migration risk?
Voice migrations do not have to be big-bang events. Many organisations move in phases, starting with specific regions or user groups.
Hybrid models can exist during transition, reducing disruption while benefits begin to accrue.
Are we putting too much into Microsoft?
For organisations already standardised on Microsoft 365, Teams Phone often extends an existing investment rather than creating a new dependency.
In many cases, organisations using Microsoft 365 E5 already have Teams Phone included in their licensing, which lowers the barrier to adoption. Voice becomes part of a broader productivity platform that users already rely on daily.
The business case beyond cost
While cost efficiency is part of the story, it is rarely the most compelling reason to consolidate voice.
Faster onboarding matters when organisations grow or restructure. A consistent voice platform reduces the friction of adding users, locations, or acquisitions.
Operational focus matters when IT teams are stretched. Simplifying voice frees time and attention for higher-value work.
Employee experience matters when collaboration is central to productivity. Reducing tool sprawl helps people communicate more naturally.
Taken together, these factors often outweigh licence savings alone.
A clearer path forward
Enterprise voice is at a turning point. The tools now exist to simplify without oversimplifying, to consolidate without surrendering control.
Microsoft Teams Phone provides a stable, familiar platform for enterprise telephony. The choice of PSTN connectivity determines whether that platform delivers on its promise or recreates old problems in a new form.
Working with a calling provider like LoopUp allows organisations to address long-standing concerns around resilience, global consistency, and operational burden, while moving toward a more coherent voice strategy.
The result is not just fewer platforms or providers. It is a voice environment that supports how modern enterprises actually operate, across locations, time zones, and teams.
Summary
Fragmented voice estates create hidden cost, risk, and complexity.Hesitation around consolidation is understandable, but maintaining the status quo carries its own growing risks.
Microsoft Teams Phone standardises enterprise voice within a widely adopted collaboration platform.
LoopUp provides the PSTN connectivity that enables Teams Phone to work at global enterprise scale.
Together, they offer a practical path to simplification without loss of control.
