Never heard of "Hard Phones". ART is designed to handle calls placed from Skinny devices that Call Manager knows about. As long as Call Manager is involved in the call, a record will be created in CDR, and that call record should be passed over to ART. Phones or faxes off a WS-X6624-FXS, or some other MGCP gateway should be able to show in ART reports.
Some pointers on ART itself:
Remember to enable CDR on the Call Manager
ART is centered around the relationship between a phone device and a user, so make sure the device is associated to one and only one user.
Be careful of Modifications, Additions and Changes--disassociate a user and the device FIRST, then delete an inactive user or defective phone.
