isr.co.ro : glossary Local loop The telephone line between the central office (switching office) and a subscriber. In most cases, it's a twisted pair of copper wires. With present technology, twisted-pair local loops can carry data at only slow-to-medium rates--up to roughly 100 kilobits/second. So local loops tend to be a bottleneck in communications links to homes and to businesses too small for a dedicated high-speed link. This is the so-called "last mile" problem. However, telephone companies are saying that sometime in the next year or two they will begin to deploy a new technology called ADSL (asymmetric digital subscribed line) that will boost those speeds by nearly a factor of 100.