CATV: Cable Television
From Network Dictionary Wiki
Cable Television (CATV), formerly called Community Antenna Television, is a communication network where multiple channels of programming material are transmitted to homes using broadband coaxial cable.
It is most commonplace in North America, Europe, Australia and East Asia, though it is present in many other countries, mainly in South America and the Middle East. Cable TV has had little success in Africa, as it is not cost-effective to lay cables in sparsely populated areas, and although so-called "wireless cable" or microwave-based systems are used, "direct-to-home" satellite television is far more popular, especially in South Africa.
Technically, both cable TV and CATV involve distributing a number of television channels collected at a central location (called a headend) to subscribers within a community by means of a network of optical fibers and/or coaxial cables and broadband amplifiers.
As in the case of radio broadcasting, the use of different frequencies allows many channels to be distributed through the same cable, without separate wires for each. The tuner of the TV, VCR or radio selects one channel from this mixed signal.
The same program is often simultaneously broadcast by radio and distributed by cable, usually at different frequencies. Other programs may be distributed by cable only; rules restricting content (e.g. regarding nudity and pornography) are often more relaxed for cable than for over-the-air TV.
Traditional cable TV systems worked strictly by way of analog signals (i.e. using standard radio waves) but many modern cable TV systems also employ the use of digital cable technology, which uses compressed digital signals, allowing them to provide many more channels than they could with analog alone.
Many cable television systems were formerly known as CATV (Community Antenna Television) systems as they were originally composed simply of a shared antenna located in a high location to which multiple households could have their TVs connected via coaxial cable. This was designed to provide access to television signals in areas where reception was traditionally poor. As cable-only networks began to appear on CATV systems, picked up via satellite rather than by antenna, the use of the term CATV has largely faded and the term cable television has taken its place.
Cable television is normally regarded as a natural monopoly, and most areas are served by a single provider, though Australia is characterised by extensive duplication.