Fiber optic (or "optical fiber") refers to the
medium and the technology associated with the transmission of information
as light impulses along a glass or plastic wire or fiber. Fiber optic wire
carries much more information than conventional copper wire and is far less
subject to electromagnetic interference. Most telephone company long-distance
lines are now fiber optic.
Transmission on fiber optic wire requires repeating at distance intervals.
The glass fiber requires more protection within an outer cable than copper.
For these reasons and because the installation of any new wiring is labor-intensive,
few communities yet have fiber optic wires or cables from the phone company's
branch office to local customers (known as local loop).
