When I had my DSL hooked up, they didn't do anything in or on the house hookups. I am assuming they did something to at the box up on the corner of the street. Then they gave me a bunch of line filters to install on the actual phone jacks in the house. I has to install these on any phone jack in the house that I didnt want to use for the DSL. I cant figure out why they would have screwed with the wiring in your house.
Can anybody confirm that the black 4 conductor cable is for the DSL line? Could the DSL be coming thru existing wiring on an unused pair?