Submarine Communication Systems

This section of the database is still under construction content heavily taken from Wikipedia.

Integrated Voice Communications System

The Integrated Voice Communications System (IVCS) is maintained by the communications division of the Operations Department. The IVCS is made up of various parts that can be cross-linked in order to provide the best form of communication for each possible situation the boat may find itself in. They are made up of announcing circuits (one-way communication), intercoms (two-way communications), sound powered communications (backup/emergency situation comms), and the Voice Over Internet Protocol (VOIP) phone system.

1 Main Circuit

1 Main Circuit (1MC) is the term for the shipboard public address circuits on United States Navy and United States Coast Guard vessels. This provides a means of transmitting general information and orders to all internal ship spaces and topside areas, and is loud enough that all embarked personnel are (normally) able to hear it. It is used to put out general information to the ship’s crew on a regular basis each day.

The system consists of an amplifier-oscillator group which is located in the IC/gyro room, a microphone control station, portable microphones at each control station and loudspeakers located throughout the ship. Control stations for the 1MC announcing system are located at the pilot house, OOD stations on the quarterdecks, aft steering and Damage Control Central area.

During an incident involving a casualty, the 1MC is a communication tool used by DCA (damage control assistant) to keep ship members alerted and informed of casualty location area, status, and incident response efforts by the DC organization.

The 1MC is divided into smaller sub-circuits, such as officer’s quarters and topside. At the option of the officer of the deck, some details are not passed on certain circuits.

The 1MC is also used for transmitting various alarm sounds to alert the crew of specific impending dangers such as an inbound torpedoes, collision, and diving/surfacing.

Some circuits function via a squaw box setup and operate as an intercom, noted below.

Common Sub-Circuit List

This section is being reviewed by the staff.

Sound Power Phones

Sound powered phones can be used as both an internal telephone and used as a two-way radio when responding to damage control incidents or at battle stations. When calling a station via the sound powered phone (unless being used as a two-way radio) the following syntax is used:

Station Being Called, Station Calling – await acknowledgement, answering station may include name of person answering – message, may include who is calling – acknowledgement


“Radio, Conn!”

“Conn, Radio, Vossler.”

“Radio, Captain, at next trip to photonics depth permission to transmit and receive crew email is approved.”

“Transmit and receive crew email, aye sir.”

VOIP Phone System

While in port and available for hookup to a landline phone line or ethernet connection to internet the VOIP phone system operates as a traditional phone system for external and internal communications. This system operates internally while underway. When answering a phone the station and person answering should be announced and then the caller should state their name, watch position as necessary, and where they are calling from as appropriate (see sound power phone syntax).

Scroll to Top