On an old episode of CSI...

Some stalker guy was living in the attic of this woman's home without her knowing. He had tapped into her phone lines which is how he knew where she was going, or some other plot-related reason.

As they're looking around, they find what looks like a Cat3 cable with the outer jacket worn away. They then proceed to take a butt set and just clamp BOTH clips across ALL the conductors of the Cat3 at the same time.