System that distributes television signals by means of coaxial or fibre-optic cables. Cable television systems originated in the U.S. in the late 1940s to improve reception in remote and hilly areas, where broadcast signals were weak. In the 1960s they were introduced in large metropolitan areas where reception is sometimes degraded by reflection of signals from tall buildings. Since the mid-1970s there has been a proliferation of cable systems that offer special services and which generally charge a monthly fee. Besides providing high-quality signals, some systems can deliver hundreds of channels. Another feature increasingly offered by cable operators is two-way, interactive communication by which viewers can, for example, participate in public-opinion polls as well as connect to the Internet. Cable operators are also involved in the development of video compression, digital transmission, and high-definition television.