Be careful when working around or testing an RJ31X provided / installed by ADT. They have such a big customer base that it allows them to purchase hundreds of thousands of RJ31X jacks. They have convinced their supplier, because of the huge numbers that they buy, to create jacks with a different (opposite) color code from the "official" ones.
Instead of the dial tone coming in on the red/green pair, it goes OUT on the red/green. This can cause much confusion if you are not aware of it. They do it for no other reason than to mess with the competition.
I had exactly that problem on a site about a year ago. Extremely frustrating until we figured it out!!
