Battle telephone circuits. Battle telephone circuits are sound-powered circuits. Vibrations of the voice actuate a diaphragm and cause an armature to move in a field of permanent magnets, thus generating electrical current. This current is conducted by wiring through the receiver, where it causes the receiver diaphragm to vibrate. Vibrations of the transmitter diaphragm are in frequency with vibrations of the receiver diaphragm; hence, sounds produced at the transmitter are reproduced at the receiver. Since no outside source of electrical power is involved, these phones may continue to function after all power systems of the ship have been knocked out. Outlets for sound-powered telephones are located in numerous stations aboard ship. The wiring interconnecting these outlets (in various combinations) constitutes the sound-powered battle telephone system. The normal damage control sound-powered circuits of a large ship are as follows:
Circuit Name Function

• 2JZ Damage and stability control Provides communication between the damage control officer and all repair control parties; also personnel stationed in pump rooms, at draft gauges, at Diesel fire pumps, and, in carriers only, primary and auxiliary flight-control stations, hangar control and conflagration stations.
• 3JZ Upper deck repair Provides communication between the officer at Repair I and each Repair I patrol party, each battle dressing station in the superstructure, and, in carriers, each hangar-deck patrol party and Repair VII.
• 4JZ Forward repair Provides communication between the officer at Repair II and each Repair II patrol party, each forward battle dressing station, and each remote valve control station forward of engineering spaces.
• 5JZ After repair Provides communication between the officer at Repair III and each Repair III patrol party, each battle dressing station aft, and each remote valve control station aft of engineering spaces.
• 6JZ Amidship repair Provides communication between the officer at Repair IV and each Repair IV patrol party, each amidship battle dressing station, and each remote valve control station amidships.
• 7JZ Engineer's repair Provides communication between the officer at Repair V and each remote valve operating station (steam and fuel oil), each engine room, each fireroom, each auxiliary engine room, and each amidship battle dressing station.
• 8JZ Flight deck repair Provides communication between the officer at Repair VIII and each flight deck patrol party, and each topside battle dressing station.   201   Circuit Name Function
• 9JZ Magazine sprinkling and ordnance repair Provides communication between the officer at Repair VI forward, Repair VI aft, sprinkling control forward, sprinkling control aft, each 5-inch powder handling room, each turret powder handling room, and damage-control station.
• 3JG Aircraft service These circuits are found on carriers only and are primarily for use by the air group for gassing planes, bomb and torpedo handling, and like services. In the event of a casualty they are to be used for disposing of gasoline, bombs and torpedoes to prevent further damage to the ship.
• 5JG Conflagration control
• 7JG Aviation ordnance
• 1JA Captains battle circuit Provides communication between the Captain and the heads of departments at their battle stations, including the damage control officer.
• 11JV Maneuvering, docking, and catapult control This circuit is provided for communication between the stations concerned with ship handling and aircraft, but may well be used by repair parties in the event of emergency.
• 12JV Engineer's (main engines) These circuits are provided for communication between all stations concerned with propulsion and auxiliary power plants, and are used by engineering damage-control party.
• 3JV Engineer's (boilers) 4JV Engineer's (fuel and stability)
• 5JV Engineer's (electrical) 1JL Lookouts (surface and sky) This circuit is primarily for conveying information from the lookouts to the officer of the deck, Captain, gunnery officer, and combat information center. Due to the locations of these stations they may be used to locate damage due to high-angle gunfire and bombs.