The various stations within a ship must be able to communicate with one another. For example, the ship’s damage-control parties must be able to communicate with Damage Control Central and the bridge during an emergency, and the bow lookouts must be able to report what they see and hear to the officer of the deck.
To accomplish this, ships need reliable means of communicating internally. In battle conditions or during other emergencies, ships may lose some or all electrical power, and battery-powered communication systems are good only as long as the batteries hold out. Also, radio systems (such as walkie-talkies) are not always effective through steel bulkheads and decks, and they broadcast radio signals into the air where they might be detected by enemy forces.
Because of these potential problems, ships must have some means of communicating internally that does not require an outside source of electrical power. For decades, the Navy has used a simple but reliable invention called the sound-powered telephone, which relies on the energy generated by the user’s voice to create enough current to power the circuit—akin to the childhood use of two tin cans connected by a string. Instead of cans and string, users plug specially designed headsets into outlets located at key points throughout the ship.
Newer ships have the Integrated Voice Communication System that combines the features of sound-powered phones, dial telephones, and intercom units into one sophisticated system with many advanced operating features. Sound-powered systems, however, remain on many ships as the primary system or as an important backup system that will continue to function in all but the worst battle-damage scenarios. Because of that, and because historical references to these important systems sometimes appear without adequate explanation, further details about them are offered.
Sound-powered systems are recognizable by the letter J in their circuit designations. Some of the more common sound-powered circuits found on board ships are:
JA Captain’s battle circuit
JC Weapons control
JL Lookouts
JW Navigation
JX Communications
1JV Maneuvering and docking
21JS Surface search and radar
22JS Air-search radar
61JS Sonar information
2JZ Damage control
Numbers may precede the J to differentiate among circuits of the same general type. For example, in a ship that has only one primary weapon system, the circuit connecting key weapons stations would be simply designated the JC circuit. But on board a ship with two major weapon systems, there would be two separate circuits, designated 1JC and 2JC.
Vital circuits are duplicated by what are called auxiliary circuits. Even though these circuits connect the same stations as the primary circuits, the wires connecting them are deliberately run through different parts of the ship so that damage to one is less likely to result in simultaneous damage to the other.
Supplementary circuits are short, direct lines used to connect key stations that need a source of quick, reliable communications. These typically use a handset, similar to a conventional telephone. For example, a supplementary circuit connects the captain’s sea cabin and the bridge, so that the officer of the deck can quickly notify the captain of matters of importance. Because supplementary circuits are not manned, most contain a buzzer system (sometimes called a growler) so that one station can alert another that communications between the two are desired.
The letter X precedes both auxiliary circuits and supplementary circuits, but you can tell the difference because supplementary circuits do not have an additional letter after the J. For example, the XJL and X22JS circuits are auxiliaries of the JL and 22JS primary circuits, while the X1J and X8J would be supplementary circuits.
Individual stations on a circuit are distinguished from each other by the addition of yet another number at the end of the sequence. For example, 22JS7 identifies outlet number 7 on the 22JS circuit. Other outlets on the same circuit would be assigned individual numbers like 22JS6 and 22JS8, and so on.
Modern ships (hopefully) may no longer have to use sound-powered systems, relying instead on contemporary equivalents, but these systems were absolutely vital through decades of naval history, and it is good to know that they remain as a backup for future operations.
