Windows operating system license requirements
When an OAS is installed on a Windows Server operating system, the operating system software requires licenses called Client Access Licenses (CALs). A CAL is a license that gives you the right to access the services of the server. Two types of Microsoft operating system CALs are available: a device-based CAL and a user-based CAL. You need to purchase the CALs separately from the ADX server.
For more information on CALs, refer to https://www.microsoft.com/en-us/licensing/product-licensing/client-access-license.