The PBX in the branch back office costs more to maintain than it ever cost to install.
The typical credit union phone system includes legacy PBX hardware that’s aging out of vendor support. All too often, firmware updates require on-site visits, carrier contracts lock in pricing with no flexibility, the system doesn’t connect to the collaboration tools staff already use, and remote employees can’t access it at all.
For a two-person IT team managing five or six branches, keeping the phones running is a full workload in itself.
Credit unions already running Microsoft 365 are moving calling into the same platform their staff uses for chat, meetings, and file sharing. Microsoft Teams becomes the phone system rather than another tool alongside it.
Teams Phone replaces the PBX, the carrier contract, and the patchwork of tools around them. Licensing, network readiness, number porting, and core system integration each shape how the migration lands. Getting them right is the difference between a clean cutover and a disruptive one.
What's driving credit unions away from legacy phone systems
The global on-premises PBX market declined 4.6% in 2025 to $1.8 billion, with Metrigy forecasting another 8.7% drop in 2026. More than half of businesses now use a cloud platform as their only phone system, and credit unions are part of that move.
The reasons are operational. A legacy credit union phone system creates drag in a few predictable areas:
- Multi-branch management: Every branch runs its own phone configuration. Adding a location, moving an extension, or changing a call flow means a vendor call or an on-site visit. The more branches, the more overhead.
- Disconnected from Microsoft 365: Most credit unions already use Teams for chat and meetings. The phone system sits completely outside that environment. Staff switch between platforms for every call, with no shared directory, presence, or call history.
- No visibility into call data: Legacy systems give little insight into call volume, wait times, or missed calls across branches. Without that data, staffing decisions and service gaps are mostly guesswork.
- Copper line exposure: Many credit unions still depend on analog lines for fax machines, elevator phones, and alarm systems. As carriers retire copper infrastructure, replacing copper-based phone lines becomes its own project on top of the phone migration.
Legacy PBX hardware has no upgrade path to a cloud-based voice platform. When a credit union is ready to move, the system gets replaced entirely.
What Microsoft Teams Phone replaces and what it adds
Microsoft Teams Phone for credit unions is already a well-established path. Microsoft holds 22% of global UCaaS seats and leads the market. Teams Phone itself has reached 26 million PSTN users, a 30% increase in 20 months. For credit unions already on Microsoft 365, the question is what changes when they turn it on.
What it replaces
Teams Phone removes the on-premises PBX and replaces it with cloud-based calling inside Microsoft Teams.
Voicemail, auto-attendants, and call queues all move into the same platform staff already use for chat and meetings. Phone numbers port over, so members keep calling the same numbers. There’s no need to reprint materials or confusing interactions with members.
The carrier relationship changes too. Instead of a standalone voice circuit tied to PBX hardware, calling runs through the cloud. How that connection works depends on the path the credit union chooses.
What it adds
Once calling lives inside Teams, it becomes the foundation for capabilities a PBX could never support.
Texting and faxing layer on without a separate platform. Contact center functionality connects directly to the same environment. Call analytics give branch and operations leaders visibility they never had.
On the AI side, Copilot brings call summaries, action item extraction, and meeting recaps into the daily workflow. These are built into the Teams platform. For credit unions, that means less time on post-call notes and more time with members.
How credit unions connect Teams to the phone network
Teams Phone handles calling inside the platform. But it still needs a connection to the public phone network so members and outside callers can reach the credit union. There are three ways to set that up, and the right choice depends on the credit union’s size, existing carrier relationships, and how much it wants to manage.
| Operator Connect | Direct Routing | Microsoft Calling Plans | |
| How it works | A carrier connects to Teams through Microsoft’s operator portal | The credit union or a partner manages session border controllers (SBCs) to route voice traffic into Teams | Microsoft provides the calling plan and phone numbers directly |
| Carrier flexibility | Choose from a list of certified operators | Use any carrier with SIP trunking | Microsoft is the carrier |
| Who manages it | The carrier handles provisioning and number management | The credit union or its partner manages the SBCs and routing | Microsoft manages everything |
| Best fit | CUs that want managed support with carrier choice | CUs with existing SIP infrastructure or complex routing needs | Smaller CUs that want the simplest setup |
For most credit unions, Operator Connect is the most practical starting point. The carrier manages the connection, numbers are provisioned through the Teams admin center, and the credit union keeps its existing phone numbers. It balances control with simplicity.
Direct Routing offers greater flexibility but requires additional infrastructure. The credit union or its managed services provider runs SBCs that connect SIP-based voice delivery to Teams. This path makes sense when the credit union has complex routing requirements or existing SIP trunk contracts worth keeping.
Microsoft Calling Plans are the simplest option but offer the least flexibility. Microsoft acts as the carrier, which limits number porting options and geographic coverage. For a credit union VoIP deployment spanning multiple branches, this path quickly runs into coverage and number availability limits.
What to evaluate before migrating
A Teams Phone migration touches more than the phone system. Licensing, network performance, carrier coordination, and core system connectivity all need clear answers before the first branch goes live.
- Microsoft 365 licensing: Teams Phone requires add-on licenses beyond a standard Microsoft 365 plan. Confirm what the credit union already has and what needs to change before provisioning begins.
- Network readiness: Voice quality depends on bandwidth, QoS configuration, and branch connectivity. Every location needs enough headroom to handle concurrent calls without degrading other traffic. Test before the migration, not after.
- Number porting timeline: Porting existing numbers to Teams takes coordination between the current carrier and the new provider. Timelines vary, and delays can push go-live dates. Start early.
- Core system integration: Credit unions run on platforms like Fiserv, FIS, or Jack Henry. The voice and network environment needs to maintain reliable, encrypted connections to those systems through and after the migration.
- Staff training: The interface changes. Call handling changes. Voicemail works differently. Staff need hands-on time with Teams calling before cutover, not a PDF and a go-live date.
- Phased vs. full cutover: Most credit unions start with one branch or department, validate the setup, and expand from there. A phased approach limits risk and gives IT time to solve problems before they scale.
How a single communications platform strengthens credit union operations
Moving calling into Microsoft Teams is the first step. Once it’s there, texting, faxing, contact center, and call analytics layer on without adding separate platforms or starting over. Each capability connects to the same environment staff already work in.
A single credit union communications platform where calling, messaging, and member engagement share one environment changes how the organization operates, leading to fewer vendors, tickets, and gaps between tools.
Momentum designs, deploys, and manages that environment across 36,000+ enterprise locations and 132,000+ active Microsoft Teams users. One provider handles network architecture, Teams Phone provisioning, and ongoing support. You get one bill, one team, and one complete solution.
Talk to a Momentum Teams expert about designing a Teams Phone migration for your credit union.
Teams Phone FAQs
Can a credit union keep its existing phone numbers when moving to Microsoft Teams?
Yes. Phone numbers port over as part of the migration. Members keep calling the same numbers they always have. No need to reprint marketing materials, update directories, or notify members of a change. The porting timeline depends on the current carrier and the connection method the credit union chooses, but the numbers themselves carry over.
How long does it take a credit union to migrate to Teams Phone?
It depends on branch count, network readiness, and how many phone numbers need to port. Many credit unions start with a single branch or department and expand from there. A small deployment can go live in a few weeks. Larger, multi-branch rollouts with complex routing typically take a few months from planning through full cutover.
Does Teams Phone work with credit union core systems?
Yes. The network and voice environment can be designed to maintain reliable, encrypted connections to core platforms like Fiserv, FIS, Jack Henry, and others. The migration changes how voice traffic is delivered, but it does not need to disrupt connectivity to the systems that run daily operations.
Do credit union employees need new desk phones for Teams Phone?
Not necessarily. Teams Phone works on certified desk phones and also on computers, mobile devices, and headsets through the Teams app. Many credit unions reduce their desk phone footprint during the migration and shift to a mix of devices that match how staff actually work across branches and remote locations.
Can a credit union run Teams Phone alongside its existing PBX during the migration?
Yes. Most migrations run both systems in parallel during the transition. This lets the credit union move one branch or department at a time, validate call quality and routing, and resolve issues before expanding. The existing PBX stays active until each location is fully cut over and verified.
