This holoprojection chamber, situated on the Executor, was located right next to Darth Vader's meditation chamber. It housed a HoloNet transceiver projection pod that Darth Vader used to communicate in secret with The Emperor on a secure channel.
Admiral Firmus Piett was ordered by Vader to maneuver the Executor away from the dangerous Hoth asteroid field. Once the ship was safe, Vader retreated to his private quarters. Leaving his meditation chamber, Vader descended a short set of stairs to reach the hologram projection pod. There, he knelt on his left knee, awaiting instructions from his master. The Emperor then revealed to him the increasing power of Luke Skywalker in the Force, emphasizing the growing danger Skywalker posed to their objectives. Vader proposed converting Skywalker to the dark side. Vader later made use of this chamber shortly after his failed capture of Luke Skywalker, immediately following the interception of a transmission indicating a probable location of the Rebel fleet.
In Star Wars: Rogue Squadron III: Rebel Strike, the endings of the Revenge of Yavin, Defiance on Dantooine, Defenders of Ralltiir, Extraction from Ralltiir, Raid at Bakura, Relics of Geonosis, and Fondor Shipyard Assault levels depicted Darth Vader in communication with Palpatine, using a chamber similar to the one on the Executor. However, it is not clear whether these scenes were intended to represent the same holoprojection chamber.