[Rathji]

One pair for sure. The thing is you have Cat5 ran as phone cable. So there are 4 pairs available.

You could do a few things to figure out which pair is live.

1) check another phone jack and see which pair that one uses. Often a contractor will do all jacks at once, and will normally use one wiring scheme on all jacks to prevent themselves from going nuts connecting them at the other end.

2) check the wiring at your utility box, as only the correct pair will be connected to the bix (or whatever you have there). Again this will only work if the same contractor did all your wiring. If it was done in stages by multiple people, all bets are off.

3) Randomly test pairs until one works. Not the best idea, but in a pinch it would work.