Science Fair Project Encyclopedia
Cable television or Community Antenna Television (CATV) (and often shortened to 'cable') is a system of providing television, FM radio programming and other services to consumers via radio waves transmitted directly to people’s televisions through fixed 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 common in Canada, the United States, Europe, most of Australasia and much of eastern Asia, though it is present in many other countries.
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 system (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 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 in which a number of 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.
History of U.S. cable TV and its regulation
During the television licensing freeze of the late 1940s, the demand for television increased. Since new television licenses were not being issued, the only way the demand was met was by Community Antenna Television. The first commercial CATV System was developed in 1948 by John Walson . He had interest in an appliance store that began to carry televisions. A major problem in selling televisions in Mahanoy City, Pennsylvania was that the stations which were available were received very poorly. Walson built an antenna on the top of a nearby mountain and strung a wire from it to his shop. A neighbor asked for the wire to be connected to his house and Walson connected it to his own house. He said he would extend the wire to anyone who would buy one of his television receivers, and in 1949 he started charging for the service.
Another system in Mahanoy City was founded by Jerrold Electronics Corp. which served the other side of town. Both were originally three-channel systems and were upgraded to five. Other systems were built: some conceived the idea independently, others didn't, and others laid claim to the title of first.
On August 1, 1949 T.J. Slowie , a secretary of the Federal Communications Commission, sent a letter to a CATV pioneer in Astoria, Oregon, L.E. Parsons , requesting he "furnish the Commission full information with respect to the nature of the system you may have developed and may be operating." He did. This is the first known involvement of the FCC in CATV. An FCC lawyer, E. Stratford Smith , determined the Commission could exercise common carrier jurisdiction over CATV. The FCC didn't act on this opinion and Smith later changed his mind after working in the cable industry for some time and testifying in Senate committee hearings. Senator and future Federal Communications Commissioner Kenneth A. Cox attended and participated in these hearings. He prepared a report entitled the Cox Report for the Senate Committee on Interstate and Foreign Commerce. This report was against CATV and supported the FCC policy of a television station in every community.
In 1959 and 1961 bills were introduced in Congress that would have determined the role of the FCC in CATV policy. The 1959 bill, which actually made it to the floor of the Senate, would have limited FCC jurisdiction to CATV systems within the contours, i.e. the broadcast range, of a single station. It was defeated. The 1961 bill proposed by the FCC would have given the Commission authority over CATV as CATV, and not as a common carrier or broadcaster. The Commission could then adopt rules and regulations "in the public interest" to govern CATV in any area covered both by CATV and broadcast television. No action was ever taken on this bill.
More important than Congressional action in determining Federal Communications Commission CATV policy were court cases and FCC hearings. Frontier Broadcasting Co. v. Collier was a hearing in which broadcasters tried to get the FCC to exercise common carrier authority over 288 CATV systems in 36 states. The broadcasters maintained that CATV went against the FCC's Sixth Report and Order, which advocated at least one television station in every community. In 1958, the FCC decided that CATV was not really a common carrier since the subscriber did not determine the programming. Carter Mountain Transmission Corp., a common carrier that already transmitted television signals by microwave to CATV systems in several Wyoming towns, wanted to add a second signal to two of the towns and add two signals to a previously unserved town. A television station in one town opposed this and protested to the FCC on the grounds of economic damage. A hearing examiner supported Carter Mountain but the Commission supported the television station. The case was taken to appeal, as most are, and the Federal Communications Commission won. "The fact that no broadcaster has actually gone off the air due to CATV competition at the time the government moved to expand its authority (nor have any since) did not stay the momentum for the expansion of regulatory authority. That some economic impact was merely plausible sufficed as the basis for government concern and government action." The FCC overruled a hearing examiner in favor of broadcasters again in the "San Diego Case". The CATV systems in San Diego, California wanted to import stations from Los Angeles, some of which could be seen in San Diego; the television stations in San Diego didn't want the signals imported. The television stations won, not allowing the signals on future cable lines in San Diego and its environs. The FCC's reasoning was to protect the present and future UHF stations in San Diego.
In the First Report and Order by the Federal Communications Commission on CATV the FCC gave itself the power to regulate CATV. This Report and Order was designed to protect small town television stations. It did this by imposing two rules, which in slightly altered form still stand: one requires that a CATV system carry all local stations in which the CATV system is in the "A" (best reception) contour of the station. The second prohibits the importation of programs from a non-local station that duplicates programming on a local station if the duplication is shown either 15 days before or 15 days after its local airing. This 1965 report reasoning is as follows: 1) CATV should carry local stations because CATV supplements, not replaces, local stations and the non-carriage of local stations gives distant stations an advantage since people will not change from the cable to the antenna to see a local station; 2) non-carriage is "inherently contrary to the public interest"; 3) CATV duplication of local programming via distant signals is unfair since broadcasters and CATV do not compete for programs on an equal footing; the FCC recommends "a reasonable measure of exclusivity".
The 1966 Second Report and Order made some minor changes in the First Report and Order and added a major regulation. This was designed to protect UHF stations in large cities. The new rule disallowed the importation of distant signals into the top 100 markets, thus making CATV profitable only in cities with poor reception. In 1968 the Supreme Court upheld the FCC's right to make rules and regulations concerning CATV. In its decision on United States v. Southwestern Cable, the "San Diego Case", it said "the Commissions authority over 'all interstate ... communications by wire or radio' permits the regulation of CATV systems."
The Birth of Public Access Television
In 1969 the FCC issued rules requiring all CATV systems with over 3500 subscribers to have facilities for local origination of programming by April 1, 1971. The date was later suspended. In 1972, Dean Burch steered the FCC into a new area of regulation. It lifted its restrictions on CATV in large cities, but now put the burden of more local programming on CATV operators. In 1976, the FCC used its rule making power to require that new systems now had to have 20 channels, and that cable providers with systems of 3500 subscribers or more had to provide PEG (public, education, and government access) channel capacity, and facilities and equipment necessary to use this capacity.
In the United States, cable television programming is often divided between basic and premium programming. Basic cable TV networks are generally transmitted without any scrambling or other special methods and thus anyone connected to the cable TV system can receive them. Basic cable networks receive at least some funding through fees paid by the cable TV systems for the right to include the network in its channel lineup. Most basic cable TV networks also include advertising to supplement the fees, due to their programming cost being greater than the fees paid by cable TV systems. Premium cable refers to networks, such as HBO and Showtime, that scramble or encrypt their signals so that only those paying additional monthly fees to their cable TV system can legally view them (via the use of cable box). Because these networks command much higher fees from cable TV systems, their programming is generally commercial free.
There are several features of cable programming that distinguish it from broadcast television. Because cable television carries more bandwidth than broadcast TV (10 to 20 times as many channels), there is room for more specialized channels catering to a particular genre or groups such as sci-fi or woman’s oriented programming. Also, because cable TV networks rely much less, or in some cases not at all, on revenue from commercials, they can feature programming (such as minority sports or ethnic programming) that draws much smaller viewer numbers than what broadcast networks would find acceptable. And finally, since cable TV signals, unlike broadcast TV, cannot be picked up by just anyone with a TV, including children, the FCC’s rules regarding acceptable content do not apply to cable TV networks, allowing greater freedom in the use of language, nudity, and violence.
The lack of restrictions on content has led to cable TV programs with more adult-oriented content such as nudity and strong language, including some premium cable networks broadcasting so-called soft-core porn programs. Premium cable networks have traditionally been the loosest with regard to content, since they require a cable box to view, making it easier to restrict children’s access to them. Thus, one can find nudity, foul language, and even soft-core pornography on these networks, though, so far, not hard-core pornography, possibly due in part to such factors as the risk of cable TV systems dropping them or legal risk. Basic cable, on the other hand, has not traditionally been as loose with regard to content. While there are no FCC rules that apply to content on basic cable networks, because most such networks rely at least partly on advertising revenue, they have succumbed to pressure from advertisers to keep their content more in line with that of broadcast TV. Thus, many basic cable networks voluntarily censor their programs, particularly with regard to language and nudity. In recent years though, some basic cable networks have begun to relax their self-imposed restrictions, particularly late at night. Thus, programs like Comedy Central’s South Park often contain content unsuitable for broadcast TV. Some basic cable networks have also recently aired R-rated movies, uncut, late at night.
Cable TV Fees and Programming Lineups
Cable TV systems impose a monthly fees depending on the number and perceived quality of the channels offered. Cable TV subscribers are offered various packages of channels one can subscribe to. The cost of each package depends on the type of channels offered (basic vs. premium) and the quantity. These fees cover the fees paid to individual networks for the right to carry their network as well as the cost of operating and maintaining the cable TV system so that their signals can reach subscribers homes. Additional fees and taxes are often tacked on by local, state, and federal governments. The fee the cable TV system must pay to a cable TV network will vary depending on whether it is a basic or premium channel and the perceived popularity of that channel. Because cable TV system are not required to carry any basic cable channel they often try and negotiate the fee they will pay for carrying a channel. Thus more popular networks thus have been able to command much higher fees then less popular networks. The fees paid to basic cable networks has a benefit in that advertisement breaks on basic cable are either absent or their number and duration are far lower than on broadcast TV, where ads make up around 25% of programming in the US.
Most cable systems divide their channel lineups into three or four basic channel packages. A must-carry rule requires all cable TV system carry local broadcast stations on their lineups. Cable TV systems are also required to offer a subscription package that provides these broadcast channels at a lower rate then the standard subscription rate. The basic programming package offered by cable TV systems is usually known as basic cable and provides access to a large number of basic cable tv networks, as well as broadcast channels, and local-access television channels. Some system refer to this package a expanded basic with their most minimal package being referred to as basic cable. In addition to the basic cable packages, all system offer premium channel add-on packages offering either just one premium network (i.e. HBO) or several premium networks for one price (i.e. HBO and Showtime together). Finally, most cable systems offer pay-per-view channels where users can watch individual movies, live programs, sports, etc. for an additional fee for single viewing at a scheduled time. Some cable systems have begun to offer on-demand programming , where customers can select programs from a list of offerings including recent releases of movies, concerts, sports, and reruns of tv shows and specials and start the program whenever they wish as if they where watching a DVD or tape. Some of the offerings have a cost similar to renting a movie at a video store while others are free.
Starting in the late 1990s, advances in digital signal compression (primarily Motorola's DigiCipher 2 technology in North America) technology have given rise to wider implementation of digital cable services. Digital cable provides many more television channels over the same available bandwidth, by converting cable TV channels to a digital signal and then compressing the signal. Currently, most system offer a hybrid analog/digital cable system. This means they offer a certain number of analog channels via basic cable service with additional channels being made available via digital cable service. Thus subscribers wishing to have access ot digital cable channels must have a special cable box to receive them. Additional subscription fees is also usually required to receive these digital channels. Digital cable channels can offer a higher quality picture then their analog counterparts though digital compression has a tendency to soften the quality of the television picture, particularly of channels that are more heavily compressed.
Many cable systems operate as local monopolies in the United States, as cable companies typically receive exclusive rights to serve a region as a result of a franchise agreement with a local government. In some areas that is changing as competition has been allowed to enter the market, including in some cases city run cable systems. The rise of DSS Satellite systems, which provide the same type of programming using small satellite receivers, has also provide competition to cable TV systems.
Cable TV in Other Countries
Cable television has spread to many parts of the world including Canada, Mexico, Europe, Japan, Asia, and Australia.
In Canada, cable television also provides viewers with access to American commercial networks that otherwise cannot be received (save for a limited number of communities located close to the U.S. border). When cable was introduced to the country in the 1970s, local broadcasters attempted to stop it, fearing loss of advertising revenue and ratings. As a result, simultaneous substitution was introduced. As it pertains to Canadian cable broadcasts, whenever an American network program is scheduled to run at the same time as an identical program originating from a Canadian broadcaster, the Canadian signal (including all local advertisements and station identification) replaces the American signal for the duration of the program. There have also been occasions where scheduled programming on an American broadcaster has been "blacked out" or replaced with different programming. This has occurred when still-active criminal cases in Canada have been made the basis of made-for-TV films or television series episodes in the United States, or when a broadcast violates a licensing agreement. (For example, in the spring of 2004, Spike TV, an American broadcaster, aired a series of James Bond films. Canadian viewers, however, saw substituted programming as a domestic broadcaster held exclusive rights to air those films in Canada.)
See also Cable television in Canada.
i-Cable Communications Limited is the holding company that runs Hong Kong's only cable television provider service. Established as Wharf Cable, the current 12-year licence will expire in 2005. It is listed on the Hong Kong Stock Exchange and NASDAQ. Wharf Holdings Limited owns 67 per cent of the cable provider and the rest amongst public shareholders.
Due to the small market, many in Hong Kong watch TV without cable. Wharf Cable is also commonly referred to as "Cable Television", and is branded as "CableTV".
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 the bandwidth available over coaxial lines. This leaves plenty of space available for other digital services such as broadband internet and digital telephony.
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 allways-on convenience, though these upgrades are expensive.
Another service being added to many cable systems is digital telephone service. Digital telephony is accomplished by installing a special telephone interface at the customer's premises that coverts 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 digital 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 perhaps future 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.
A chart showing the North American cable television bandplan can be found here.
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