1MC

1MC is the term for the shipboard public address on U.S. Navy vessels. This system broadcasts throughout the entire ship, and is loud enough that all embarked personnel are able to (normally) hear it. In movies, calls to General Quarters are made over the 1MC. 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 words are not passed on certain circuits.There are also specialized circuits such as the 5MC for Flight Deck control. "MC" is an acronym for Main Circuit. These have mostly phased out by using Integrated Voice Communication System (IVCS) nets.

Usage examples

* General Quarters - "This is not a drill, this is not a drill, General Quarters, General Quarters! All hands man your battlestations. Go up and forward on your starboard side, down and aft on your port side. General Quarters, General Quarters!
* Sweepers - "Sweepers, Sweepers, man your brooms. Give the ship a clean sweep down both fore and aft! Sweep down all lower decks, ladder wells and passageways! Dump all garbage clear of the fantail! Now sweepers."
* 8 O'Clock Reports - "Now lay before the mast all eight O'Clock reports."
* Men Working Aloft - "There are men working aloft onboard (ship) , do not rotate, radiate, or energize any electric or electronic equipment, start gas turbines, or sound the ship's whisle while men are working aloft onboard (ship)." (Passed every fifteen minutes and by all adjacent ships)
* Divers Over the Side - "There are divers over the side, do not rotate screws, cycle rudders, take suction from or discharge to the sea or operate any underwater equipment without first contacting the Officer of the Deck and the diving supervisor." (Passed every fifteen minutes)
* Reveille - "Reveille! Reveille! Reveille! All hands heave out and trice up reveille!"
* Taps - "Taps! Taps! Lights out! Maintain silence about the decks. Taps."
* Darken Ship - "Darken Ship! Make Darken Ship reports to Damage Control Central."
* Fire - "Fire, Fire, Fire, Class (A, B, C, or D) Fire in Compartment (Compartment Number). Away the Flying Squad (ships fire fighting team) away, provide form repair 2 (Or nearest Repair station)
* Breakaway music - Popular music played at the conclusion of an underway replenishment evolution. It is used to motivate the crew.
* Submarine diving - "On the 1MC dive, dive, dive." (followed by two klaxon blasts)