46 CFR § 113.35-5 - Electric engine order telegraph systems.
(b) Each engineroom indicator must be capable of acknowledgment of orders.
(d) Each telegraph instrument must meet the protection requirements of § 111.01-9 of this chapter.
(e) Each system must have an alarm which -
(1) Automatically sounds and visually signals a loss of power to the system;
(2) Is on the navigating bridge; and
(3) Has a means to reduce the audible signal from 100 percent to not less than 50 percent.