InPerson operates somewhat like a multiline telephone. A telephone icon launches InPerson, places calls, and rings when you receive a call.
While telephones are just for talking, InPerson is for interacting as if you were face-to-face. Callers appear in an interactive video window if their workstations are equipped with video cameras; if not, static pictures of them appear. You can then interact with the callers and work on a file together, in real time.