His office contained an elaborate array of communication devices, 50 speaking tubes, 50 electric bells and 50 annunciators which connected to all departments.
The now mostly obsolete speaking tube served to transmit sounds to a remote location with minimal loss and distortion, as a simple coaxial cable or waveguide does for electrical signals.
These holes acted as the receiving area for the acoustics, which were transmitted to the back of the throne via a speaking tube, and into the king's ear.
