46 CFR § 113.30-25 - Detailed requirements.
(a) Multiple stations must be able to communicate at the same time.
(b) The loss of one component of the system must not disable the rest of the system.
(c) The system must be able to operate under full load for the same period of operation as required for the emergency generator. See 46 CFR 112.05-5, Table 112.05-5(a).
(d) Each voice-communication station device in the weather must be in a proper enclosure as required in 46 CFR 111.01-9. The audible-signal device must be outside the station enclosure.
(e) Each station in a navigating bridge or a machinery space must be in an enclosure meeting at least Type 2 of NEMA 250 or IP 22 of IEC 60529 (both incorporated by reference; see 46 CFR 110.10-1).
(f) In a noisy location, such as an engine room, there must be a booth or other equipment to permit reliable voice communication while the vessel is operating.
(g) In a space throughout which the voice communication station audible-signal device cannot be heard, there must be another audible-signal device or a visual-device, such as a light, either of which is energized from the final emergency bus.
(h) If two or more voice communication stations are near each other, there must be a means that indicates the station called.
(i) Each connection box must meet at least Type 4 or 4X of NEMA 250 or IP 56 of IEC 60529.
(j) Voice communication cables must run as close to the fore-and-aft centerline of the vessel as practicable.
(1) No cable for voice communication may run through any space at high risk of fire such as machinery rooms and galleys, unless it is technically impracticable to route it otherwise or it must serve circuits within those spaces.
(2) Each cable running through any space at high risk of fire must meet IEC 60331-11 and IEC 60331-21 (both incorporated by reference; see 46 CFR 110.10-1).
(k) If the communications system uses a sound-powered telephone, the following requirements also apply:
(1) Each station except one regulated by paragraph (d) of this section must include a permanently wired handset with a push-to-talk button and a hanger for the handset.
(2) The hanger must be constructed so that it holds the handset away from the bulkhead and so that the motion of the vessel will not dislodge the handset.
(3) Each talking circuit must be electrically independent of each calling circuit.
(4) No short circuit, open circuit, or ground on either side of a calling circuit may affect a talking circuit.
(5) Each circuit must be insulated from ground.