A telephone company provides near broadband service with DSL by using lines it already has. Twisted pair connects most telephones to a local telephone switch. It's what we call the local loop , two wires making a metallic circuit to switching equipment. Although better, more capable wire exists, twisted pair makes a cost effective, good quality, low noise connection to the switch. Over the decades twisted pair, otherwise called unshielded twisted pair or UTP, has been installed throughout America for local telephone service.
Twisted pair forms the backbone of local telephone infrastructure.
The FCC says as of 1998, the United States had179,822,123 local loops, the vast majority still on copper. The twisting is deliberate. Wires laid in straight lines next to each other pick up signals from each other. It's something called induction, a problem that produces cross talk with voice calls and, mangles information in data calls. Regular, sharp twists of the pair counter the electrical forces at work.