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

television tuner In electronics and radio, a tuner is a type of receiver subsystem that receives RF transmissions, such as AM or FM broadcasts, and converts the selected carrier frequency into a form suitable for further processing or output, such as to a ...

that receives a

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

(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; ...

into an

analog signal An analog signal (American English) or analogue signal (British and Commonwealth English) is any continuous-time signal representing some other quantity, i.e., ''analogous'' to another quantity. For example, in an analog audio signal, the ins ...

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, instantaneous phase and frequency, ...

set. Some also have an

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gam ...

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 content is signal transmission, transmitted via radio waves from the terrestrial (Earth-based) transmitter of a TV station to a TV rece ...

signals received by a

television antenna A television antenna, also called a television aerial (in British English), is an antenna specifically designed for use with a television receiver (TV) to receive terrestrial over-the-air (OTA) broadcast television signals from a television s ...

, 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 previo ...

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.ITU Radio Regulations, Section IV. Radio Stations and Systems ...

, which has always required a

set-top box A set-top box (STB), also known as a cable converter box, cable box, receiver, or simply box, and historically television decoder or a converter, is an information appliance device that generally contains a Tuner (radio)#Television, TV tuner inpu ...

either to operate the

big Big or BIG may refer to: * Big, of great size or degree Film and television * Big (film), ''Big'' (film), a 1988 fantasy-comedy film starring Tom Hanks * ''Big'', a 2023 Taiwanese children's film starring Van Fan and Chie Tanaka * ''Big!'', a ...

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 An integrated receiver/decoder (IRD) is an electronic device used to receive 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 a ...

(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.ITU Radio Regulations, Section IV. Radio Stations and Systems ...

s (DBS). In

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia. It constitutes the southern half of the Korea, Korean Peninsula and borders North Korea along the Korean Demilitarized Zone, with the Yellow Sea to the west and t ...

, 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 tel ...

boxes convert from ATSC to

NTSC NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170. In 1953, a second ...

, while in most of

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and other places such as

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

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) o ...

(DVB) to

PAL Phase Alternating Line (PAL) is a color encoding system for analog 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 almost all countries in Latin 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 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 ...

standards (and in fact further complicated them), and due to varying

frequency allocation Frequency allocation (or spectrum allocation) is the part of spectrum management dealing with the designation and regulation of the electromagnetic spectrum into frequency bands, normally done by governments in most countries. Because radio pr ...

s and

bandplan The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularl ...

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 ...

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 commonl ...

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 the analog passthrough feature only allow older, analog-only TVs to view digital TV. Those with analog pass-through allow both digital and a ...

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 North America's largest standards and technology trade organization representing more than 1,200 technology companies. CTA is led by CEO and Vice Chair Gary J. Shapiro. Trade shows CES 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 government that regulates communications by radio, television, wire, internet, wi-fi, satellite, and cable across the United States. The FCC maintains j ...

(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 incl ...

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 Commun ...

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 station, television and radio stations thro ...

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 (an abbreviation of its original name, Columbia Broadcasting System), is an American commercial broadcast television and radio network serving as the flagship property of the CBS Entertainme ...

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 Corporation, Inc., formerly Circuit City Stores, Inc., 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 th ...

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

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

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 A television show, TV program (), or simply a TV show, is the general reference to any content produced for viewing on a television set that is broadcast via Terrestrial television, over-the-air, Satellite television, satellite, and cable te ...

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 prototyping, software programming. A prototype ...

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

LG Electronics LG Electronics Inc. () is a South Korean Multinational corporation, multinational major appliance and consumer electronics corporation headquartered in Yeouido-dong, Seoul, South Korea. LG Electronics is a part of LG, LG Corporation, the fourth ...

, 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, Thomson SA, and Thomson Multimedia) is a French multinational corporation that provides technology products and services for the communication, media and entertainment industries. Headquarter ...

used an

RCA RCA Corporation was a major American electronics company, which was founded in 1919 as the Radio Corporation of America. It was initially a patent pool, patent trust owned by General Electric (GE), Westinghouse Electric Corporation, Westinghou ...

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 fo ...

s using

Program and System Information Protocol The Program and System Information Protocol (PSIP) is the MPEG (Moving Picture Experts Group, a video and audio industry group) and privately defined program-specific information originally defined by General Instrument for the DigiCipher 2 sys ...

(PSIP). The devices showed program details,

V-chip V-chip is a technology used in television set receivers in Canada, Mexico, 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 telev ...

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 Comcast Holdings,Before the AT&T Broadband, AT&T merger in 2001, the parent company was Comcast Holdings Corporation. Comcast Holdings Corporation now refers to a subsidiary of Comcast Corporation, not th ...

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

shopping networks Shopping channels (also referred to in British English as teleshopping) are television programs or specialty channels dedicated to home shopping. These channels typically feature live presentations and product demonstrations, with on-air hosts and ...

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

modulation Signal modulation is the process of varying one or more properties of a periodic waveform in electronics and telecommunication for the purpose of transmitting information. The process encodes information in form of the modulation or message ...

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 sign ...

, 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 D ...

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 December 2015. 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 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 valuable goods, or taking hostages. Those who conduct acts of piracy are call ...

. 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, television shows and films Digital distribution, digitally on request. These multimedia are accessed without a traditional video playback device and a typica ...

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 ...

. 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 Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulat ...

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

Pace plc Pace plc was a British company which 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. T ...

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 Fe ...

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 telev ...

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.

Other countries

Some countries have also introduced digital television and ended analog over-the-air transmissions. Most new TVs feature a digital 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 digital tuner, an external converter box must be purchased and used. A converter box takes the digital signal from the antenna and outputs

composite video Composite video, also known as CVBS (composite video baseband signal or color, video, blanking and sync), is an analog video format that combines image information—such as brightness (luminance), color (chrominance), and synchronization, int ...

(for SD TVs) or

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

passthrough Passthrough (or pass-through) may refer to: * Passthrough (electronics), a device used to pass an unmodified signal ** Analog passthrough ** Pass through device (automotive) ** Passthrough, a term used to describe the use of cameras with head-up d ...

("LOOP OUT" which does not provide the box's output signal, but only provides the raw antenna input signal to watch analog channels via a TV set's tuner if analog broadcasts have not ended yet or to connect another 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 (radio frequency modulator) is an electronic device used to convert signals from devices such as media players, VCRs and game consoles to a format that can be handled by a device designed to receive a modulated RF input, such ...

in a converter box.

References