An Interrotron works like a teleprompter that shows the interviewer or director’s face as opposed to the script scrolling above the camera. The Director also sees the talent (interviewee) or the subject being filmed.

Now to be specific: One builds the Interrotron by building two Teleprompters, a talent unit (with the camera with which you are shooting) and a director’s unit (a Teleprompter with another camera) This way each person can have a face-to-face conversation with the interviewer while simultaneously looking directly into the camera.