Via Flickr:
"From the window with the golden grill, the Sultan or the Valide Sultan was able to follow deliberations of the council without being noticed. The window could be reached from the imperial quarters in the adjacent Tower of Justice (Adalet Kulesi). When the sultan rapped on the grill or drew the red curtain, the Council session was terminated, and the viziers were summoned one by one to the Audience Hall (Arz Odası) to present their reports to the sultan."
Topkapi Palace Wikipedia
en.wikipedia.org/wiki/Topkap%C4%B1_Palace
Suggested readings from Amazon.com:
In The Topkapi Palace
Palace of Gold and Light: Treasures from the Topkapi, Istanbul
Topkapi Palace Inside and Out: A Guide to the Topkapi Palace Museum and Grounds