A leased line is a private telecommunications circuit between two or more locations provided according to a commercial contract. It is sometimes also known as a private circuit, private connect, and as a data line. Traditionally, leased lines were used by businesses to connect geographically distant offices for phone and networking. More recently leased lines are used to establish connectivity between businesses for networking between private Data center, Colocation data centre (Colo), and their public clouds.
Unlike traditional telephone lines in the public switched telephone network (PSTN) leased lines are generally not switched circuits, and therefore do not have an associated telephone number. Each side of the line is permanently connected, always active and dedicated to the other. Leased lines can be used for telephone, Internet, or other data communication services. Some are ringdown services, and some connect to a private branch exchange (PBX) or network router.