A digital television adapter (DTA), commonly known as a converter box or decoder box, is a television tuner that receives a

digital television Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative adva ...

(DTV) transmission, and converts the

digital signal A digital signal is a signal that represents data as a sequence of discrete values; at any given time it can only take on, at most, one of a finite number of values. This contrasts with an analog signal, which represents continuous values; a ...

into an

analog signal An analog signal or analogue signal (see spelling differences) is any continuous signal representing some other quantity, i.e., ''analogous'' to another quantity. For example, in an analog audio signal, the instantaneous signal voltage varies ...

that can be received and displayed on an

analog television Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, phase and frequency of an analog ...

set. Some also have an HDMI output since some TVs with HDMI do not have a digital tuner. The input digital signal may be over-the-air

terrestrial television Terrestrial television or over-the-air television (OTA) is a type of television broadcasting in which the signal transmission occurs via radio waves from the terrestrial (Earth-based) transmitter of a TV station to a TV receiver having an ante ...

signals received by a television antenna, or signals from a

digital cable Digital cable is the distribution of cable television using digital data and video compression. The technology was first developed by General Instrument. By 2000, most cable companies offered digital features, eventually replacing their previ ...

system. It normally does not refer to satellite TV, which has always required a

set-top box A set-top box (STB), also colloquially known as a cable box and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of s ...

either to operate the big

satellite dish A satellite dish is a dish-shaped type of parabolic antenna designed to receive or transmit information by radio waves to or from a communication satellite. The term most commonly means a dish which receives direct-broadcast satellite televisio ...

, or to be the integrated receiver/decoder (IRD) in the case of

direct-broadcast satellite Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commo ...

s (DBS). In

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

and

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...

, these

ATSC tuner An ATSC (Advanced Television Systems Committee) tuner, often called an ATSC receiver or HDTV tuner, is a type of television tuner that allows reception of digital television (DTV) television channels that use ATSC standards, as transmitted by te ...

boxes convert from

ATSC Advanced Television Systems Committee (ATSC) standards are an American set of standards for digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard and, like th ...

NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...

, while in most of

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and other places such as

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

and most Asian countries, they convert from

Digital Video Broadcasting Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) ...

(DVB) to

PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

, and in Japan, the Philippines and most countries in South America, they convert from

ISDB-T Integrated Services Digital Broadcasting (ISDB; Japanese: , ''Tōgō dejitaru hōsō sābisu'') is a Japanese broadcasting standard for digital television (DTV) and digital radio. ISDB supersedes both the NTSC-J analog television system and ...

to either NTSC or PAL. Because the DTV transition did nothing to reduce the number of broadcast television system standards (and in fact further complicated them), and due to varying

frequency allocation Frequency allocation (or spectrum allocation or spectrum management) is the allocation and regulation of the electromagnetic spectrum into radio frequency bands, normally done by governments in most countries. Because radio propagation does ...

s and

bandplan A frequency plan, bandplan, band plan or wavelength plan is a plan for using a particular band of radio frequencies, that are a portion of the electromagnetic spectrum. Each frequency plan defines the frequency range to be included, how channels ...

s, there are many other combinations specific to other countries.

United States

On June 12, 2009, all full-power

transmissions ended in the United States. Viewers who watch

broadcast television Broadcast television systems (or terrestrial television systems outside the US and Canada) are the encoding or formatting systems for the transmission and reception of terrestrial television signals. Analog television systems were standardized b ...

on older analog TV sets must use a digital converter box. Since many of the low-power TV stations continued to broadcast in analog for a while, consumers who watch low-power stations needed an adapter with an

analog passthrough Analog passthrough is a feature found on some digital-to-analog television converter boxes. Boxes without analog passthrough only allow digital TV (ATSC standard) to be viewed on older, analog-only ( NTSC standard) TVs. Those with analog passthro ...

feature that allows the viewer to watch both digital and analog signals. Viewers who receive their television signals through cable or satellite were not affected by this change and did not need a digital television adapter (however, see the cable TV exception below). Additionally, viewers who have newer televisions with built-in digital ATSC tuners will not need an external digital television adapter. The United States government had set up a program to offer consumers a $40 "coupon" which could be used toward the purchase of a

coupon-eligible converter box A coupon-eligible converter box (CECB) was a digital television adapter that met eligibility specifications for subsidy "coupons" from the United States government. The subsidy program was enacted to provide terrestrial television viewers with ...

; that program ended in July 2009.

History

At the

Consumer Electronics Association The Consumer Technology Association (CTA) is a standard and trade organization representing 1,376 consumer technology companies in the United States. CTA works to influence public policy, holds events such as the Consumer Electronics Show (CE ...

's Entertainment Technology Policy Summit in January 2006,

Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdicti ...

(FCC)

Commissioner A commissioner (commonly abbreviated as Comm'r) is, in principle, a member of a commission or an individual who has been given a commission (official charge or authority to do something). In practice, the title of commissioner has evolved to in ...

Jonathan Adelstein Jonathan Steven Adelstein is an American political appointee and trade association president. He was nominated to posts by Republican President George W. Bush and Democratic President Barack Obama, serving as a Commissioner of the Federal Commu ...

said many Americans did not know about the February 17, 2006, deadline for ending analog TV. Furthermore, he said, too many people were still buying analog TV sets, meaning more demand for converter boxes. And even if people found out what they would have to do, converter boxes might not do the job adequately.

Tribune Broadcasting Tribune Broadcasting Company, LLC was an American media company which operated as a subsidiary of Tribune Media, a media conglomerate based in Chicago, Illinois. The group owned and operated television and radio stations throughout the United St ...

chief technology officer Ira Goldstone said just buying a converter box did not necessarily mean getting the latest technology. Bob Seidel of CBS said companies (especially in countries other than the US) might use cheaper tuners, and people would need new television antennas for proper reception.

Circuit City Circuit City is an American consumer electronics retail company, which was founded in 1949 by Samuel Wurtzel as the Wards Company, operated stores across the United States, and pioneered the electronics superstore format in the 1970s. After m ...

Chairman Alan McCollough opposed converter boxes, saying people should just buy digital TVs, and

television network A television network or television broadcaster is a telecommunications network for distribution of television program content, where a central operation provides programming to many television stations or pay television providers. Until the mid ...

s should offer only

widescreen Widescreen images are displayed within a set of aspect ratio (image), aspect ratios (relationship of image width to height) used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ...

-format

television program Television, sometimes shortened to TV, is a telecommunication Media (communication), medium for transmitting moving images and sound. The term can refer to a television set, or the medium of Transmission (telecommunications), television tra ...

ming as an incentive to do that.

Prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and software programming. A prototype is generally used to ...

s of the first converter boxes appeared at the NAB show in 2006.

LG Electronics LG Electronics Inc. () is a South Korean multinational electronics company headquartered in Yeouido-dong, Seoul, South Korea. LG Electronics is a part of LG Corporation, the fourth largest '' chaebol'' in South Korea, and often considered ...

, which took over

Zenith Electronics Zenith Electronics, LLC, is an American research and development company that develops ATSC and digital rights management technologies. It is owned by the South Korean company LG Electronics. Zenith was previously an American brand of consumer e ...

in 1999, showed its model connected to a Zenith TV from 1980, while

Thomson Consumer Electronics Vantiva SA, formerly Technicolor SA, Thomson SARL, and Thomson Multimedia, is a French multinational corporation that provides creative services and technology products for the communication, media and entertainment industries. Vantiva's headq ...

used an

RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...

TV from 1987 for its demonstration. Both boxes shown used

electronic program guide Electronic programming guides (EPGs) and interactive programming guides (IPGs) are menu-based systems that provide users of television, radio and other media applications with continuously updated menus that display scheduling information for ...

s using

Program and System Information Protocol The Program and System Information Protocol (PSIP) is the MPEG (a video and audio industry group) and privately defined program-specific information originally defined by General Instrument for the DigiCipher 2 system and later extended for the AT ...

(PSIP). The devices showed program details, V-chip ratings and signal strength. Thomson's model stored three days of TV listings, allowed parental controls, and could set a VCR.

Differences for cable customers

Cable TV systems are under no deadline to convert to digital TV. However, many

Comcast Comcast Corporation (formerly known as American Cable Systems and Comcast Holdings),Before the AT&T merger in 2001, the parent company was Comcast Holdings Corporation. Comcast Holdings Corporation now refers to a subsidiary of Comcast Corpora ...

(and some other cable TV) customers are finding all of their non-local and non-

shopping networks Shopping channels (also known in British English as teleshopping) are a type of television program or specialty channel devoted to home shopping. Their formats typically feature live presentations and demonstrations of products, hosted by on-air pr ...

eliminated on various dates, even though only a few are needed for additional

channels. CECBs (Coupon-eligible converter boxes) will not work on these systems because cable ATSC uses

256QAM Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message signa ...

modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the '' carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informat ...

instead of 8VSB, and so a separate but similar DTA with a QAM tuner is necessary. If the cable company takes away analog channels, at least two of these adapters must be provided for free by the cable company for at least three years so that customers can continue to watch the same channels with existing equipment. Cable companies were required to provide some analog service until October 2006. After that, taking away analog channels allowed faster Internet and more HD channels. An adapter from the cable provider was needed even for digital TVs if the company

scrambled Scrambled eggs is a dish made from eggs (usually chicken eggs) stirred, whipped or beaten together while being gently heated, typically with salt, butter, oil and sometimes other ingredients. Preparation Only eggs are necessary to make scramble ...

its digital signals to prevent

piracy Piracy is an act of robbery or criminal violence by ship or boat-borne attackers upon another ship or a coastal area, typically with the goal of stealing cargo and other valuable goods. Those who conduct acts of piracy are called pirates, v ...

. A digital transport adapter will allow viewing of basic channels, often as many as 99, but not premium channels. It will also not allow

video on demand Video on demand (VOD) is a media distribution system that allows users to access videos without a traditional video playback device and the constraints of a typical static broadcasting schedule. In the 20th century, broadcasting in the form of ...

pay-per-view Pay-per-view (PPV) is a type of pay television or webcast service that enables a viewer to pay to watch individual events via private telecast. Events can be purchased through a multichannel television platform using their electronic program g ...

. DTAs also allow analog sets to receive digital signals using RF output on channel 3 or 4, using

coaxial cable Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a p ...

. Other versions of the DTA (including with an HDMI output) are available.

Pace plc Pace plc was a British company who developed set-top boxes (STBs), advanced residential gateways, software and services for the pay-TV and broadband services industry. Pace's customers included cable, telco, satellite and IPTV operators. Th ...

developed the XiD-P digital transport adapter for

, allowing 4K service and offering the potential to expand the DTA from one-way to two-way. This would involve adding IP capability.

European Union

Most countries that have switched to digital TV use

DVB-T DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in Feb ...

broadcasting with

MPEG-2 MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression methods, ...

MP@ML or H.264 encoding. However, some have considered switching to

DVB-T2 DVB-T2 is an abbreviation for "Digital Video Broadcasting – Second Generation Terrestrial"; it is the extension of the television standard DVB-T, issued by the consortium DVB, devised for the broadcast transmission of digital terrestrial tele ...

such as the UK, being the first to test DVB-T2. This results in a number of different combinations for external digital receivers with the MPEG-2s sold at about €15 to €35 and the MPEG-4 ones reaching €25 to €150. Currently, all set top boxes sold in the EU cannot exceed 0.5 W in standby mode.

Russia

Russia has also introduced digital TV and is now (03.12.2018 – 03.06.2019) ending analog over-the-air transmission. Most new TVs feature a

tuner which allows reception of digital over-the-air TV without need of an external device such a converter box. If using a TV set without a DVB-T2 tuner, an external converter box must be purchased and used. This converter box takes the digital signal from the antenna and outputs

composite video Composite video is an analog video signal format that carries standard-definition video (typically at 525 lines or 625 lines) as a single channel. Video information is encoded on one channel, unlike the higher-quality S-Video (two channe ...

(for SD TVs) or

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controlle ...

(for HD TVs). The RF/antenna output, if present on the box, is usually just a

passthrough In signal processing, a passthrough is a logic gate that enables a signal to "pass through" unaltered, sometimes with little alteration. Sometimes the concept of a "passthrough" can also involve daisy chain logic. Examples of passthroughs * Ana ...

("LOOP OUT" which does not provide the box's output signal, but only provides the raw antenna input signal – to watch analog channels via the TV's tuner if analog broadcast has not ended yet or to connect another DVB-T2 capable device to the same antenna feed) because even older TVs usually have at least composite input; this removes a need for an

RF modulator An RF modulator (or radio frequency modulator) is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source. RF modulators are used to convert signals from devices such as media players, VCRs a ...

in the converter box.

References