In my home built in 1950, I have one wall phone jack. (I do not know what phone/data services the previous residents had) On taking off the jack cover, I found that the wires from the cover to the wall plate were not connected. Attached to the wall plate, I have 2 "cables" (?) or sets of wires. One comes out of the wall. This looks like the original (it has a thick black cover around the wires) has four individual copper strands, with yellow, black, red and green covering. The other, which comes from a different direction (it disappears into the floor) has two strands: yellow and black.
The individual color coded copper strands are all attached to the wall plate, including BOTH yellow wires.
My question: 1) do both yellow wires need to be attached? (the one from the black/yellow/green/red set of four and the one from the black/yellow set of two)
2) I am getting a DSL modem from Century Link along with their local phone service. The salesperson told me the phone would connect into the modem and NOT into the phone jack independently. Do I need all 4 colored wires attached via the jack cover terminals to the wall plate terminals?