Hi,
Do I need RDS user CALs if I plan to purchase a Windows Server External Connector License?
The external connector is only for external users who are not employees while RDS CAL is used when you deploye RDS servers.
Once you have bought windows server per user/per device CAL and also would like to utilize the remote desktop service for multiple users/devices, you shall configure the RDS deployment and buy additional RDS CAL (also per user/device).
So when you deploy Windows EC license + RDS, you may consider RDS EC CAL.
Moreover, you could confirm with VLSC on the CAL details by phone call.
VLSC contact:
https://www.microsoft.com/Licensing/servicecenter/Help/Contact.aspx
Hope this helps.
Thanks,
Jenny