The modern submarine periscope consists essentially of a long tube, the top of which is just above the water when diving, while the lower end passes through a stuffing box on the shell of the boat into the control-room.
blast door the corridor turns left into the control room which is in the center of the bunker.
The speaker is muted automatically when the control room muted automatically when the control room mute is active, to prevent feedback.
There is a glass panel looking into the control room.
The cameras are located throughout the complex, and monitored round-the-clock from a purpose-built control room.