Will I no longer be able to use fax with Teams calling?

The telephone system is to be phased out, with Microsoft Teams taking over telephony in future. Then the order management team pipes up: ‘And what do we do about our fax number and the orders?’ A detailed question quickly turns into what appears to be a deal-breaker for the entire migration.

As with many myths, there is a grain of truth to this. Microsoft Teams does not support fax services. However, this does not mean that, after switching to Teams you will no longer be able to send faxes. Fax and Teams coexist without any problems. You simply need to keep the technical aspects separate.

Microsoft Teams Phone is designed for voice communication. Microsoft does not provide native fax integration. You should therefore not base your migration planning on integrating fax machines or fax servers directly into Teams.

Occasionally, attempts are made to connect fax machines to Teams’ SIP interface via an analogue telephone adapter (ATA). Technically, this is possible in principle. However, it is not a good choice for reliable fax communication.

Experience shows that problems can arise quickly, particularly with multi-page documents: the first page arrives, but the second might not. This is not a viable situation for business-critical processes.

The more sensible approach: Teams handles the phone calls, whilst faxing remains separate from Teams. With Telekom’s CompanyFlex, there are two ways to do this.

In the simplest case, you exclude the fax number from the range of numbers used for Microsoft Teams.

Telekom’s CompanyFlex plans allow you to assign number ranges to different SIP trunks. Put simply, a SIP trunk is the IP-based connection between the public telephone network and the relevant telephony solution.

Your employees’ phone numbers are then routed to Teams via a SIP trunk, whilst the fax number is routed via a second one. An existing telephone system could be connected at the other end of this second trunk. However, a fax-to-email service is often a good option: incoming faxes are received digitally and forwarded as files to a specified email inbox.

A typical example: A company uses the number range 0228 12345-00 to -99. In future, employees’ direct lines are to ring in Microsoft Teams, whilst the fax number -40 – which has been in use for years – is to remain unchanged. If the number range can be divided up accordingly, the -40 is simply assigned to a separate fax solution. Nothing changes for customers and business partners. They continue to dial the same number.

It is not always possible to split up a block of telephone numbers as you wish. This is precisely where migration becomes an interesting option.

Imagine that the fax number is in the middle of the number range. Immediately before and after it are extensions that are to be used in Teams in future. The existing number granularity may then not be sufficient to move just the fax number to a different SIP trunk.

Changing the fax number would be one option. In practice, however, this is often not an option: a fax number has been on file with customers and suppliers for years, appears on forms or is firmly embedded in business processes.

For such cases, Telekom offers Inbound Fax Routing. With this service, an incoming call to the fax number is recognised within the Telekom network – even before it is routed to the line. Instead of following the normal route to the Teams SIP trunk, the fax traffic is diverted beforehand and redirected to a separate fax infrastructure. This could be a fax-to-email service or another fax platform.

The main advantage is that the familiar fax number remains the same, even though it falls within the Teams number range.

Telekom sets up the inbound fax routing free of charge. The infrastructure, or the service to which the fax traffic is forwarded, must be provided separately.

The ‘fax myth’ highlights a fundamental pattern in the modernisation of business telephony: not every function of the old telephone system needs to be replicated within teams at a later stage. The more important question is which communication channels are actually still needed – and how they can be integrated effectively into the new architecture.

You should therefore clarify the following before the migration:

• What other fax numbers are there?
• Are they actually still in use?
• Do the existing numbers have to be retained?
• Can they be assigned to a separate infrastructure based on number granularity?
• Or is inbound fax routing required because of the number range?
• Should we continue to use a physical fax machine, or would a fax-to-email service be a better option?

This turns what might seem like an obstacle into a manageable planning task. If you don’t want to tackle it on your own: In the free migration consultation , our experts will review your current set-up, check number ranges and fax routes, and draw up a recommendation for your team’s telephony system.

Microsoft Teams does not support fax. However, switching your telephony to Teams does not mean you have to do without fax. The key is not to force the integration of fax into Teams, but to provide a suitable technical workaround – via a second SIP trunk or via inbound fax routing.

And that’s a good guiding principle for any Teams migration: not every existing feature needs to be moved to Teams. It just needs to work reliably afterwards.