Regulation 37
At least two independent means shall be provided for communicating
orders from the navigating bridge to the position in the machinery
space or in the control room from which the engines are normally controlled:
one of these shall be an engine-room telegraph which provides visual
indication of the orders and responses both in the machinery spaces
and on the navigating bridge. The second means of communication shall
be independent of the engine-room telegraph and shall also provide
for verification of engine orders and responses. A means of communication
which provides for verification of both engine orders and responses
shall also be provided from the navigating bridge and the engine-room
to any other position from which the speed or direction of thrust
of the propellers may be controlled.