All over the ship there are different divisions working to keep the ship moving and running smoothly. To communicate between one another there are several different sound powered circuits. The different circuits are labeled by small brass plates on the jack boxes. The 2JV circuit is for engineering. Having different circuits makes it easier to each division to communicate without being bothered by the other divisions around the ship.

The sound powered phone system is a very simple system. Just a set of hand sets located around the different spaces and a whole lot of wiring. Some of the circuits are amplified so they are easier to hear in loud spaces, like the engine rooms. There is also a set method of using the phones. They are not to be used to talk with your buddy on watch in the aft engine room, besides everyone on the circuit will hear you.

To use the system correctly first you mention the station you are calling. Then you state where you are calling from. Then wait until who you are calling answers. Then state why you are calling.

Here is an example.

Me: “Central, MER1”

EOOW:”Central”

Me : "Request permission to shift fuel oil suction forward.”

EOOW: “Permission to shift fuel oil suction forward.”

Me: “Permission to shift fuel oil suction forward. MER1 Aye!”

I then head down toward the valves and make last call.

Me: “Aye! Shifting Fuel oil suction forward.”

Then I go and switch the tank we are using to use fro the main engines fuel supply.

Me: “ Central, MER1”

EOOW: “Central”

Me : "Completed shifting fuel oil suction forward.”

EOOW: “Aye! Completed shifting fuel oil suction forward. Central out”

That whole conversation may seem strange, but it gets the point across to both parities. Both people know what is happening and both know the other side knows what is happening. Also the EOOW will log when I told him I was starting to shift and when I was done.

Other sections around engineering will also hear this same conversation. So they will also know there is something going on in the forward engine room. So incase something goes wrong and there is a problem. People can automatically react and not have to ask a whole lot of questions.