In telephone systems nomenclature, a long line is a transmission line in a long-distance communications network such as carrier systems, microwave radio relay links, geosynchronous satellite links, underground cables, aerial cables and open wire, and Submarine communications cables. In the United States, some of this technology was spun off into the corporate entity known as AT&T Long Distance with the breakup of AT&T in 1984. Prior to then, the AT&T Long Lines division of the Bell System, which was what AT&T called itself when it was responsible for providing both long distance and local telephone service before the 1984 breakup, provided maintenance and installation of long line facilities for the Bell System's long distance service.