The imager located in Atrus and Catherine's fore-chamber on the island of Myst is a holographic device derived from similar D'ni technology. It is a floor-based unit capable of displaying 3D imagery suspended in the air above the emitter grid, as well as 2D imagery restricted to the plane of the emitter grid itself.
The imager is controlled using a small panel recessed into the wall beside the stairs. Entering a number between 00 and 99 will bring up the relevant entry in the imager. The only existing entries are in slots 08, 40, 47, and 67. Messages can be deleted from the system by pressing the red selection button on the control panel during the second set of high-pitched beeps the control panel makes after making a selection.