From Microsoft Technet Forum: If the multifunction printer is connected to a Windows Server network. A multifunction printer accesses server software to; receive an IP address, to receive a job, to communicate that the job is finished, etc. In short, it communicates with the server software. If the multifunction printer is accessing any server software licensed via the Server / CAL licensing model it requires a CAL for that software. The one caveat is, if your users who use the printer have CALs then the printer is covered by their use via their CALs. If not then the printer itself requires a device CAL. The same CAL requirement applies to any other type of networked device – such as networked scanners, networked fax machines, etc. Devices that do not connect to the network or the server software (generally referred to as peripherals) do not require CALs.
Let's say I'm an administrator in a company (hospital for example) with 900 pc users, working in shifts. So I have 300 pc's, used by these 900 users. For the email and file servers, I purchased device 300 CAL's. I also manage 100 MFP's who send email through the exchange server, contact the LDAP-server for searching colleagues email adresses. I also configured the MFP's to send scanned documents to some shared network folders. Do I have to purchase 100 extra device CAL's?