This is a User Client Access License (CAL) for Windows 2003 Server Standard. A CAL is needed for every device or user accessing the server for using file services, printing services, remote access service, or terminal services, or any authenticated users accessing Windows 2003 as a Web server or an application server. For a significant number of authenticated Internet users, an External Connector license(ECL) is available.

With Windows 2003, CALs can be accounted for either per server or per user or device. This CAL is for licensing per User; Device CALs are a separate item. Either CAL can be used in per-server mode. A User CAL allows access for one user regardless of device used (i.e. an employee who accesses the server from work and from home), a Device CAL allows access for one computer regardless of the number of users (i.e. a shared workstation).