With a Device CAL, you purchase a CAL for every device that accesses your server, regardless of the number of users who use that device to access the server. Device CALs may make more economic and administrative sense if your company has workers who share devices, for example, on different work shifts.
If the workstations in your organization are networked, you likely depend on network server software to perform certain functions, such as file and print sharing. To access this server software legally, a Client Access License (CAL) may be required. A CAL is not a software product; rather, it is a license that gives a user the right to access the services of the server.