Adding a phone jack
 

I want to stick a single-line phone jack here -

http://www.mightywombat.com/wire.jpg

I assume I should see what color wires are being used on other phones in my house, then find those wires in this mess. Then what?

For the sake of this discussion, lets say the red and green wires are in use elsewhere. Should I red and green and splice an outlet in the middle of them?

Gimme some guidence here. Thanks!

That looks like at least 4 pair wire. The first line in a given dwelling unit is the blue/white(ring)(-) white/blue(tip)(+) pair. Obtain a modular jack which will mount to the box shown-failing that use a low voltage foldable plaster/drywall mount.

Attach the wires as identified above to the jack using the included plastic punchdown tool, or if screw terminals identified for quad cable (red/green/yellow/black), remember red=ring and green=tip.

If still confused, post again, and I'll try to confuse you further. :thumbsup: