A CO is a structure used by telecommunications companies to house equipment needed to direct telephone calls and data traffic. A CO, also known as telephone switching centers, wire centers, or telephone exchanges, is centralized in a specific locality. The CO has switching equipment which enables the handling of local or long distance calls for that locality. Telephone lines are connected to the CO on a local loop. A central office is typically a multi-story, windowless, concrete structure, designed to withstand major weather events such as hurricanes or tornadoes.