 | This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages)
|
_during_ship%27s_return_to_Norfolk.jpg)
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.[1]
During an incident involving a casualty, the 1MC is a communication tool used by DCAs (damage control assistants) 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.[1]
The 1MC is also used for transmitting various alarm sounds to alert the crew of specific impending dangers such as an inbound anti-ship missile, chemical attack, collision, or a flight deck crash.