An access circuit from the network edge to the customer premises, a local loop is a short haul circuit for access to a local exchange. The most common example of a local loop is an electrically based, two-wire, copper access circuit between a telephone company central office (CO) switching center and a residential or small business premises. Such a circuit is provisioned over a single unshielded twisted pair (UTP), within which two wires are required to complete the electrical circuit, with the current in one wire opposite to the current in the other, and with both wires carrying the information signal. The two conductors comprise an electrical loop, with one wire carrying the go signal and the other carrying the electrical return signal. In the broader contemporary sense, any access circuit between the customer premises and the edge of the telco network, or that of any other service provider, is termed a local loop, whether it is electrically based or employs optical or radio energy. See also last mile.
A logical network interface on a computer having TCP/IP networking software. A local loop interface is used for the interprocess communication of two processes on the same machine. Modeled within the kernel memory, it is faster than a connection made through a real-network interface.