Dammit, you beat me to it. As JK said, telephone wiring does NOT have enough twists to get away with 100BT ether. in fact, many versions of phone wires have NO twists at all, which is a BAD THING. Look at the ends of the wire coming out of the shielding. If they're flat, you're in trouble. If they're twisted, it may work until your wife turns on her hair dryer or someone uses the blender.