Take the adapter, and turn it upside down. You should observe that the bottom fits into the top. Use a pocketknife, small screwdriver, battle axe etc. to remove the bottom. Don't break it.
Detach the two wires not connected to charged poles, and scrap em. Detach the other two wires as well. Take your rheostat, and mount it on the outside of the box, drilling a small hole in the box, to run wires through.
Run wire from the charged connections from the line jack, through the rheostat, to the charged poles. (see diagram).
positive line
\/ +---------+
---------..... : :
linejack+ :......#:rheostat :#........(fuse)....[=====]
---------.. : :
:... +---------+
:............#.........................[=====]
negative line
Key: # - Rheostate poles
. - Wiring path
[=]- Outside posts
Attach the fuse somewhere in the line if you feel like it.
When the phone rings 90 volts of pulsing DC power get shot down
your line, and can really fuck up whatever you have the chart box
hooked up to. Therefore, the fuse is a good idea. You can also hook a switch up to the wiring, to give you more control over when power starts to flow. Once all the wiring is complete, push the wires and the fuse into the casing, and reclose it. Then tape around the side of the box, to hold the wires that come out to the rheostat down. I highly recommend that you mark the charged posts with a marker, so you can easily identify them.
Naturally, the main purpose of the chart box is to leech Ma Bell just like she leeches you.
Hail Discordia!
Naturally, the main purpose of the chart box is to leech Ma Bell!