Coaxial cable is often used to transmit
cable television into the house.
Cable television or Community Antenna Television (CATV) (often shortened to cable) is a system of providing television, FM radio programming and other services to consumers via radio frequency signals transmitted directly to people’s televisions through fixed optical fibers or coaxial cables as opposed to the over-the-air method used in traditional television broadcasting (via radio waves) in which a television antenna is required.
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.
Cable television deployments
Australia
Cable television services have been available in Australia since 1995. There are currently three major and four minor digital cable television providers in Australia - Foxtel, which is a 50/50 joint agreement by Telstra and News Corp, Optus TV and Austar. A newcomer, SelecTV, provides a cheaper service with a more limited array of channels and features. Other minor providers include TransACT, Bright Telecommunications and Neighbourhood Cable, which only operate in specific regional areas.
Services, channels and usability have drastically improved since the days of analogue. While many people outside the capital cities are still unable to reach the cable network, satellite services provided by the top providers have now been able to provide the same standard of quality and usability (Video on Demand, Live TV Manipulation, Dolby Digital) that cable subscribers are able to access.
Most providers are able to offer in excess of 60 channels, including 24-hour news services, movie channels, on-demand events and films, as well as terrestrial digital (DVB) free-to-air channels. Features such as timeshifting, on-demand recording, games and interactive TV are also available. Channels include but aren't limited to Discovery Channel, History Channel, Showtime Australia, Sky News Australia, Movie Network (A group of 3 separate movie channels), CNN, BBC World, MTV, ESPN and more.
Due to its history, financial backing and market dominance, most locally produced content and channels are either owned directly by Foxtel or through subsidiary companies. Channels that Foxtel own are then wholesaled to other providers, while individual channels not owned by Foxel will sell their licensing rights in content sharing agreements. This way, all providers are able to share from the same pool of channels, while still being able to set their own pricing, packages and brand.
In terms of coverage, Foxtel's cable network covers most of Sydney, Melbourne, Brisbane, Adelaide, and Perth. Optus's network covers small parts of Sydney, Melbourne, and Brisbane, though its restrictive subscription rules means that many people living in apartments or confined living areas are unable to be connected. Austar is available by satellite in regional and rural Australia, but does have a small cable network in the city of Darwin. Austar and Foxtel only compete for customers in the Gold Coast but by a mutual non-compete agreement, Foxtel limits its market to the capital cities and Austar limits its market to regional and rural areas.
The other provider, TransACT, is only available in the city of Canberra, where a custom cable network was developed. A simular situation exists in Perth where a small area is covered by Bright Telecommunications as well in parts of Geelong, Ballarat and Mildura that are reached by Neighbourhood Cable.
Canada
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Hong Kong
Only one traditional cable provider operates in Hong Kong, i-Cable Communications Limited (branded as "CableTV"). Another three operators offers pay-TV via DSL, they are Now Broadband TV (PCCW), HKBN Digital TV and TVB PayVision.
Many in Hong Kong instead watch subscription TV using satellite systems like STAR TV.
Mexico
The first cable system started to operate in the early Sixties in Monterrey, as a CATV service (an antenna at the top of the Loma Larga, which could get TV signals from South Texas). Most of the other major cities didn't develop cable systems until the late Eighties, due to government censorship. By 1989 the industry had had a major impulse with the founding of Multivisión—a MMDS system who started to develop its own channels in Spanish—and the later development of companies such as Cablemas and Megacable.
Over the past few years, many US networks have started to develop content for the Latin American market, such as CNN en Español, MTV, Cartoon Network, Disney Channel, and others. The country also has a DTH service called SKY (Televisa & News Corp. owned). Recently DirecTV merged with Sky. The dominant company nowadays is Megacable and Grupo HEVI.
Republic of Ireland
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Singapore
StarHub Cable Vision is the sole cable television operator in Singapore, where private ownership of satellite dishes is banned. StarHub Cable Vision was formed as a result of a merger between StarHub and Singapore Cable Vision on 15 May 2002. The latter first began broadcasting as a terrestrial pay-television operator in 1992 as the first cable network was not completed until 1995. Around 15% of households and offices in Singapore are connected to the StarHub network.
United Kingdom
In the UK Cable Television had its origins in 1938, when the first Community Antenna TV systems were setup in towns including Bristol and Hull, for homes which couldn't receive transmissions over the air; however these signals were on the 405-line system. In the 1960s Rediffusion Vision was setup to provide cable television in the newer 625-line and PAL formats.
In the early 1980s Rediffusion Vision supplemented its service with other channels including The Music Box, Screensport, Sky Channel and TEN. The service was renamed to Rediffusion Cablevision.
In the United Kingdom, the current generation of cable television began in the late 1980s with the issue of franchises to many local operators. These small operations proved uneconomic and there has been a continuing process of consolidation and re-financing.
By 2000 the two principal cable operators were NTL and Telewest. NTL's cable service was originally known as CableTel and grew rapidly through the acquisition of, among others, ComTel (which itself had bought Telecential), Comcast, Diamond Cable and finally, in 1999, the residential and small business operations of Cable & Wireless. Telewest also steadily acquired local operators.
In 2005 it was announced that NTL and Telewest would merge, after a period of co-operation in the preceding few years. This merger was completed on 3rd March 2006 with the company being named ntl Incorporated. For the time being the two brand names and services will still be marketed separately however are to be slowly integrated to create a single cable operator for more than 95% of the UK market, likely under the Virgin Group brand if NTL's April 2006 aqusition of Virgin Mobile is accepted.
There are a small number of other surviving cable television companies in the UK outside of NTL including Kingston Communications (East Riding of Yorkshire) and WightCable (Isle of Wight, Ayrshire, Carlisle and Lancashire).
Cable TV faces intense competition from SkyDigital's satellite television service, although most channels on that platform are also carried on cable (however they do lack features- for example interaction news or football - available to Sky Digital viewers). Very few channels are now exclusive to cable, usually channels showing local programming. However, subscription-funded digital terrestrial television proved less of a competitive threat, as ITV Digital went into liquidation in 2002. The re-launch of DTTV as the free Freeview service has been a success in introducing people to multichannel digital TV and seems not to have adversely affected the growth of cable and satellite subscribers.
Another potential source of competition in the future will be TV over broadband. This was initially launched, using ADSL, in London, where it is provided by HomeChoice. An IPTV service was also provided in Hull by Kingston Communications, but this ceased operations in April 2006. As the speed and availability of broadband connections increase, more TV content can be delivered using protocols such as IPTV.
United States
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Europe
According to the European Audiovisual Observatory, there was 58 millions cable households in the European Union as at 31 December 2004, i.e. a rate of penetration of 32 % of the television households. 5.7 millions were connected to digital networks.
Switzerland
In Switzerland, there is practically no household that doesn't have cable TV. Ironically, despite this good coverage, Switzerland has only a few state TV stations (two each for the German, French and Italian-speaking parts of the country); there are no private stations with an outreach comparable to these state channels. To watch news or political information; Swiss channels are preferred, but in the entertainment sector (feature movies, comedies, talk shows), private TV stations from Germany, France and Italy are dominant.
Other cable-based services
Coaxial cables are capable of bi-directional carriage of signals as well as the transmission of large amounts of data. Cable television signals use only a portion of the bandwidth available over coaxial lines. This leaves plenty of space available for other digital services such as broadband internet and cable telephony.
Unlike North America, many cable operators in Europe have already introduced telephone services, which operate just like existing fixed line operators.
Broadband internet is achieved over coaxial cable by using cable modems to convert the network data into a type of digital signal that can be transferred over coaxial cable. One problem with some cable systems is the older amplifiers placed along the cable routes are unidirectional thus in order to allow for uploading of data the customer would need to use an analog modem to provide for the upstream connection. This limited the upstream speed to 56k and prevented the always-on convenience broadband internet typically provides. Many large cable systems have upgraded or are upgrading their equipment to allow for bi-directional signals, thus allowing for greater upload speed and always-on convenience, though these upgrades are expensive.
Another service being added to many cable systems is cable telephone service. This service involves installing a special telephone interface at the customer's premises that converts the analog signals from the customer's in-home wiring into a digital signal, which is then sent on the local loop (replacing the analog last mile, or POTS) to the company's switching center, where it is connected to the PSTN. The biggest obstacle to cable telephone service is the need for nearly 100% reliable service for emergency calls. One of the standards available for digital cable telephony, PacketCable, seems to be the most promising and able to work with the Quality of Service demands of traditional analog POTS service. The biggest advantage to digital cable telephone service is similar to the advantage of digital cable TV, namely that data can be compressed, resulting in much less bandwidth used than a dedicated analog circuit-switched service. Other advantages include better voice quality and integration to a VoIP network providing cheap or unlimited nationwide and international calling. Note that in most cases, digital cable telephone service is separate from cable modem service being offered by many cable companies and does not rely on IP traffic or the Internet.