Honestly, it doesn't matter. If your contractor uses CAT5 cable, which is used for network cables like ethernet, it uses 4 pairs of wire. You can use a regular phone jack to terminate it so it should be fine. You'd only need to use a 6 or 8 conductor if you actually used the cable as a network connection. In my house, I ran 2 CAT 5 cables, 1 for phone use and the other for network use. I have one terminated as a phone and the other as an 8 conductor.