To use Call2Teams and Call2Teams Go, you need a Microsoft 365 license per employee, an available Microsoft 365 license, and one Microsoft Teams Phone license per solution.
For Call2Teams and Call2Teams Go, you must have a Microsoft 365 license for each employee, as well as an extra available Microsoft 365 license (the available Microsoft 365 license is only necessary during setup or updates).
If you are using Call2Teams Go, you only need one Microsoft Teams Phone license per solution.
If you wish to use Call2Teams, you need a Microsoft Teams Phone license for each user.
The reason you need at least one Microsoft Teams Phone license is that it triggers a Microsoft Teams Phone Resource Account license, which is required to use Call2Teams and Call2Teams Go.
Note: The Microsoft Teams Phone Resource Account license must be activated through the Microsoft portal. If the Microsoft portal is in Danish, the license is called Microsoft Teams-telefonressourcekonto.
If you also want the ability to create conference calls in Microsoft Teams that external phone numbers can dial into, you will need the Microsoft Teams Audio Conferencing license.
If the Microsoft portal is in Danish, the license is called Microsoft Teams-lydmøde.
You can view an overview of the contents of the different Microsoft 365 licenses here.