Problem with a phone jack...

[PeterB]

There's no question that the jack works for DSL but not for voice-- if I unplug the DSL at the jack in question, and plug in a phone, it doesn't work for the phone.

Anybody know, which colors are used for voice and which for DSL? That could prove it, using a multimeter as mikebw is saying. But that still doesn't help me, since I don't have easy access to the problem splice.

Edit: in the link Carm gave, no doubt that the jack in question is the "unused phone line" that's causing the problem...