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

television tuner A tuner is a subsystem that receives radio frequency (RF) transmissions, such as FM broadcasting, and converts the selected carrier frequency and its associated bandwidth into a fixed frequency that is suitable for further processing, usually be ...

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 into an analog signal that can be received and displayed on an analog television 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 A television antenna (TV aerial) is an antenna specifically designed for use with a television receiver (TV) to receive over-the-air broadcast television signals from a television station. Television reception is dependent upon the antenna as ...

, or signals from a digital cable system. It normally does not refer to

satellite TV 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 ...

, 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 sign ...

either to operate the

big Big or BIG may refer to: * Big, of great size or degree Film and television * ''Big'' (film), a 1988 fantasy-comedy film starring Tom Hanks * ''Big!'', a Discovery Channel television show * ''Richard Hammond's Big'', a television show present ...

satellite dish, or to be the

integrated receiver/decoder An integrated receiver/decoder (IRD) is an electronic device used to pick up a radio-frequency signal and convert digital information transmitted in it. Consumer IRDs Consumer IRDs, commonly called set-top boxes, are used by end users and are ...

(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 and

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korean Peninsula and sharing a land border with North Korea. Its western border is formed by the Yellow Sea, while its eas ...

, 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 to

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 subcontinent of Eurasia and it is located entirel ...

and other places such as Australia and most Asian countries, they convert from Digital Video Broadcasting (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 to either NTSC or PAL. Because the

DTV transition The digital television transition, also called the digital switchover (DSO), the analogue switch/sign-off (ASO), the digital migration, or the analogue shutdown, is the process in which older analogue television broadcasting technology is conv ...

did nothing to reduce the number of

broadcast television system 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 by ...

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 analog television transmissions ended in the United States. Viewers who watch broadcast television on older analog TV sets must use a digital converter box. Since many of the

low-power TV Low-power broadcasting is broadcasting by a broadcast station at a low transmitter power output to a smaller service area than "full power" stations within the same region. It is often distinguished from "micropower broadcasting" (more commonly " ...

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

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 CBS Broadcasting Inc., commonly shortened to CBS, the abbreviation of its former legal name Columbia Broadcasting System, is an American commercial broadcast television and radio network serving as the flagship property of the CBS Entertainm ...

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 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 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 ratio greater than t ...

-format

television program Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, ...

ming as an incentive to do that. Prototypes 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 a ...

, 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 V-chip is a technology used in television set receivers in Canada, Brazil and the United States, that allows the blocking of programs based on their ratings category. It is intended for use by parents to manage their children's television view ...

ratings and signal strength. Thomson's model stored three days of TV listings, allowed parental controls, and could set a

VCR A videocassette recorder (VCR) or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other source on a removable, magnetic tape videocassette, and can play back the recording. ...

Differences for cable customers

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

eliminated on various dates, even though only a few are needed for additional digital cable 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 instead of

8VSB 8VSB is the modulation method used for broadcast in the ATSC digital television standard. ATSC and 8VSB modulation is used primarily in North America; in contrast, the DVB-T standard uses COFDM. A modulation method specifies how the radio sig ...

, and so a separate but similar DTA with a

QAM tuner QAM is a digital television standard using quadrature amplitude modulation. It is the format by which digital cable channels are encoded and transmitted via cable television providers. QAM is used in a variety of communications systems such as Di ...

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 scrambled ...

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 ...

or pay-per-view. DTAs also allow analog sets to receive digital signals using RF output on channel 3 or 4, using coaxial cable. 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 Comcast, 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 broadcasting with MPEG-2 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 (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 ("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