Communication between navigating bridge and machinery space-
Every ship shall be provided with, two independent means for communicating from the navigating bridge to the position in the machinery space or machinery control room. One of the means shall be an engine room telegraph.
Means of communication shall also be provided to any other position from which the main engines may be controlled.
You may also know engineer’s alarm:
Every ship shall be provided with an engineers alarm which shall be clearly audible in the engineers accommodation when operated from a position in the machinery space or machinery control room.