I am designing a network and I've come to the point of specifying out the number of CALs required for this network. Microsoft licensing has always confused me, it's just not always clear to me.

I plan to have 1 2008 std domain controller, another 2008 server (not a domain controller) and 200 Windows 7 devices connected to the domain for domain services.

The 200 W7 devices will all authenticate to the domain controller with the same domain account. (this is a special type of network, not a user workstation network)

Therefore, do I need to purchase 200 CALS for the 200 devices, or can I purchase say 10 CALS (user CALS) as the amount of unique user accounts is very low.

Many thanks for looking.