Microsoft Windows Server CAL 2012 1 Client (R18-03665)
Licensing software with CALs and MLs can be complicated due to the technical nature of server products and networks. Microsoft offers a device-based CAL (Device CAL) or a user-based CAL (User CAL) for purchase. In addition, an External Connector (EC) license is offered for some products as an optional alternative to address specific customer scenarios.
For managing devices, Microsoft offers Server MLs for managing server Operating System Environments (OSEs). For managing non-server devices, Microsoft offers OSE Client MLs and User Client MLs.
This overview is for reference purposes only. Before purchasing, you should visit the "How to Buy" section for each product and consult your Microsoft representative or local reseller regarding your specific licensing needs.
User CALs
With the User CAL, you purchase a CAL for every user who accesses the server to use services such as file storage or printing, regardless of the number of devices they use for that access. Purchasing a User CAL might make more sense if your company's employees need to have roaming access to the corporate network by using multiple devices, or from unknown devices, or if you simply have more devices than users in your organization.