Fax migration touches the network before it touches the app.
Teams that treat fax as a simple app swap run into problems fast. They sign up for a cloud fax platform and then discover they still have analog lines to disconnect, numbers to port, and compliance requirements to carry over. The fax itself is easy to set up, the infrastructure behind it takes more planning.
That planning gets easier when you break the project into phases. Organizations that have moved faxing into Microsoft Teams successfully tend to follow a consistent sequence: inventory first, then numbers, then analog lines, then the app.
The steps below walk through each phase so you can plan and execute the move without interrupting a workflow your organization still depends on.
What to inventory before you move
Before anything changes, document what you have. Most organizations find more fax activity than they expected once they start looking. Understanding how cloud faxing works and how the in-tenant model compares to traditional options gives useful context for the decisions ahead. The list below covers what to gather before the migration starts.
- Active fax numbers: List every number in use, who owns it, and what it connects to. Some numbers route to shared machines. Others serve individual lines in specific departments.
- Monthly fax volume: Pull send and receive counts by number. Low-volume lines may not need to be ported. They can be consolidated onto fewer numbers during the move.
- Dependent workflows: Identify which departments and processes rely on fax. Healthcare organizations often have clinical intake tied to specific numbers. Legal teams may use fax for court filings. These workflows set the priority order for migration.
- Compliance and retention requirements: Confirm how long fax records need to be stored and where. Regulated industries like healthcare and finance have specific retention rules. Cloud fax platforms that store records inside your Microsoft 365 tenant keep this simple.
- Analog line inventory: Count how many copper lines carry fax traffic. Some of those lines may also serve alarms, elevators, or building security systems.
Porting your fax numbers
Once you know which numbers matter, the next step is moving them. Number porting transfers your existing fax numbers from your current carrier to the provider that will handle them inside Microsoft Teams.
The process works the same way it does for voice lines. Your new provider submits a port request to your current carrier with your account details, the numbers to transfer, and a letter of authorization. The FCC requires simple ports (single-line, no complex switch work) to be processed in one business day. Multi-line business port fax numbers requests are more involved and typically take one to three weeks depending on the carrier and how many numbers are in the batch.
Gather your current account details before you start. You will need the account number, authorized name, and billing address from your existing carrier. Most providers also require a Customer Service Record (CSR), which lists the exact numbers and services on the account. Having this ready before the port request goes in avoids back-and-forth that slows the timeline.
Your existing lines stay active until the port completes. There is no gap in service. Patients, clients, and vendors keep reaching the same number throughout the transition.
Retiring the analog lines
Porting moves the numbers. Retiring the lines removes the copper.
Fax machines have been one of the last devices keeping analog lines active in many buildings. Once the numbers port to a cloud provider, those copper lines no longer carry fax traffic and can be disconnected. This is where most of the ongoing cost savings land, since analog lines carry monthly recurring charges that have been climbing for years. Some carriers have raised per-line pricing sharply as they push remaining customers off legacy infrastructure, turning what used to be a low fixed cost into a growing line item.
The FCC’s March 2026 Network and Services Modernization Order streamlined the process for carriers to retire copper infrastructure, reducing regulatory barriers and compressing disconnection timelines. Carriers have already begun decommissioning copper in hundreds of wire centers nationwide. The window to migrate off copper on your own schedule is getting shorter.
Fax lines rarely exist in isolation. When you plan your analog line replacement, check for other devices sharing the same copper infrastructure: elevator emergency phones, fire alarm panels, building security systems, postage meters, and gate controls. Each needs its own migration path. Organizations that handle POTS replacement alongside fax migration avoid revisiting the same lines twice.
Setting up faxing in Microsoft Teams
With numbers ported and analog lines scheduled for disconnection, the fax application itself is the final configuration step.
1. Assign numbers and user access
Map each ported fax number to the correct department or user group inside Microsoft Teams. The admin assigns numbers through the Teams admin center, the same interface used for voice. Users authenticate with their existing Microsoft 365 credentials, so there is no separate login to manage.
2. Point storage at SharePoint
One of the key advantages of in-tenant Microsoft Teams faxing setup is that fax records write directly to SharePoint. Configure the storage location so that sent and received faxes land in the correct document library. This keeps records under your existing retention policies and access controls.
3. Build cover page templates
Set up cover page templates that match your organization’s branding. Departments with specific compliance language (healthcare disclaimers, legal confidentiality notices) get their own templates. Users select the right one when sending a fax from Microsoft Teams.
4. Configure delivery notifications
Set up inbound fax notifications so users know when a fax arrives. Teams can route notifications to specific channels, email addresses, or individual users based on the receiving number. For departments with high fax volume, configure routing rules that direct incoming faxes to shared document libraries rather than individual inboxes.
Validating and rolling out
Before the old hardware comes out, confirm everything works.
Start with a test group. Pick a department with moderate fax volume and have them send a fax from Teams to both internal and external recipients. Confirm that inbound faxes arrive, records write to SharePoint correctly, and cover pages render as expected. The day-to-day sending workflow is straightforward, but testing catches configuration issues before they reach a wider group.
Roll out in waves. Move one department at a time rather than switching everyone over at once. Each wave gives you a chance to catch issues and adjust templates, permissions, or storage paths before the next group goes live. Once the final group is active, decommission the old fax machines and cancel any remaining analog line contracts. Document the cutover date for each department so your compliance team has a clear record of when fax storage moved from the old system to SharePoint.
What a clean fax migration looks like
A clean fax migration follows the same pattern every time: inventory, port, retire, configure, validate. The entire process runs in weeks for most organizations, and fax never goes down during the transition because the old lines stay active until the new setup is tested and confirmed.
The difference between a smooth migration and a difficult one is scope. Organizations that treat fax as an isolated app swap miss the network side: the analog lines, the number porting, the other devices sharing that copper. When you plan for all of it, the project stays on track.
Momentum manages fax migrations inside Microsoft Teams alongside voice, network, and POTS replacement projects for organizations with 132,000+ active Teams users across 36,000+ enterprise locations. One provider handles the numbers, the lines, and the app.
Talk to a Momentum faxing expert about planning a Teams faxing migration that retires your analog lines without any downtime.
FAQs
How long does it take to port a fax number?
Simple, single-line ports are processed in one business day under FCC rules. Multi-line business ports typically take one to three weeks depending on your current carrier and the number of lines involved. Your existing fax lines stay active until the port completes, so there is no gap in service.
Can I keep faxing during the migration?
Yes. The existing analog lines and fax numbers remain active throughout the porting process. The old setup keeps running until the new Teams-based fax is tested and confirmed. You disconnect the analog lines only after everything is validated.
Do I need new hardware to fax from Microsoft Teams?
No. Faxing from Teams runs entirely in software. Users send and receive faxes from their existing desktops, laptops, and mobile devices using their Microsoft 365 credentials. No fax machine, modem, or analog line is required.
What happens to fax records stored on the old system?
Records already stored on your previous fax system stay there until you migrate or archive them. New faxes sent and received through Microsoft Teams write directly to SharePoint, where they fall under your existing retention and access policies. Plan to export or archive older records before decommissioning the legacy system so nothing is lost during the transition.
Can I fax to recipients who still use traditional fax machines?
Yes. Cloud faxing from Microsoft Teams sends and receives using standard fax protocols, so it works with any traditional fax machine or fax number on the other end. The recipient does not need to be using Teams or any specific platform. From their side, the fax arrives the same way it always has.
