Exchange Server 2010 Standard 5 Device CALs through the Microsoft Open Business Licensing Program
This product comes pre-bundled with 5 CALs. If you need additional CALs you may order them seperately.
The Standard CAL is designed to help users be more productive from virtually any platform browser or mobile device with new features in Exchange Server 2010 that help manage communications overload and lower helpdesk costs. The Standard CAL works with either server edition.
A Device CAL permits one device (used by any user) to access or use Exchange Server. Device CALs are likely to be more cost-effective than User CALs if there are multiple users per device (for example a call center or an airport kiosk). This product comes pre-bundled with 5 CALs. You can order additional CALs if needed.