A one way mirror reflects the image of the director/interviewer, in front of the camera lens.  The subject makes eye contact with the director... and simultaneously does the same with the camera. 

EyeLiner®:  The basics of a teleprompter are obvious here; however, this unit requires no electricity and turns the reflected image, left to right correct

Select these Images below for related information

 Exploded view of device
 Shipping case
  Motion control shot of director &      camera view of subject