Activate Block anonymous calls and you will be unavailable for anonymous incoming calls, Your phone will not ring.
You can create also a list with phone numbers (DND list) that will be blocked if this number is calling you.
Example:
<param name="Telephony.DnD.AnonymousCallBlock" value="0"/><param name="Telephony.DnD.List.Active" value="0"/><param name="Telephony.DnD.List.0.Name" value=""/><param name="Telephony.DnD.List.0.Number" value=""/>