A pair of copper wires runs from a box at the road to a box (often called an entrance bridge) at your house. From there, the pair of wires is connected to each phone jack in your house (usually using red and green wires).
How do I find a live telephone wire?
Touch the + probe of the multimeter to the green and - probe to the red wires. If you have a second line, + to black and - to yellow. If you get a low DC voltage reading across a pair of wires (red-green or black-yellow), around 48v, you know that you are connected to the telephone company.
Do telephone wires go underground?
So, why arent telephone lines underground? There are two methods used to move cables underground. The cheapest is open trenching. This involves digging into the earth, laying down large stretches of cabling and backfilling the trenches later.