Extended Data Services (now XDS, previously EDS), is an American standard classified under

Electronic Industries Alliance The Electronic Industries Alliance (EIA; until 1997 Electronic Industries Association) was an American standards organization, standards and trade organization composed as an alliance of trade associations for electronics manufacturers in the ...

standard EIA-608

for the delivery of any ancillary

data Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...

(

metadata Metadata (or metainformation) is "data that provides information about other data", but not the content of the data itself, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive ...

) to be sent with 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, ...

program, or any other

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 ...

video signal Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) ...

. XDS is used by

TV station A television station is a set of equipment managed by a business, organisation or other entity such as an amateur television (ATV) operator, that transmits video content and audio content via radio waves directly from a transmitter on the earth's ...

s, TV networks, and

TV 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 over-the-air, satellite, and cable, or distributed digitally on streaming platf ...

syndication

distributor A distributor is an electric and mechanical device used in the ignition system of older spark-ignition engines. The distributor's main function is to route electricity from the ignition coil to each spark plug at the correct time. Design ...

s in the US for several purposes. Here are some of the most common uses of XDS: * The "autoclock" system delivers

time Time is the continuous progression of existence that occurs in an apparently irreversible process, irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequ ...

data via an XDS "Time-of-Day Packet" for automatically setting the

clock A clock or chronometer is a device that measures and displays time. The clock is one of the oldest Invention, human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, a ...

of newer TVs & VCRs sold in the US. Most

PBS The Public Broadcasting Service (PBS) is an American public broadcaster and non-commercial, free-to-air television network based in Arlington, Virginia. PBS is a publicly funded nonprofit organization and the most prominent provider of educat ...

stations provide this service. * Rudimentary program information which can be displayed on-screen, such as the name and remaining time of the program, *

Station identification Station identification (ident, network ID, channel ID or bumper (broadcasting), bumper) is the practice of radio and television stations and broadcast network, networks identifying themselves on-air, typically by means of a call sign or brand na ...

, * V-chip

content rating A content rating (also known as maturity rating) rates the suitability of TV shows, movies, comic books, or video games to this primary targeted audience. A content rating usually places a media source into one of a number of different categories, ...

s data. XDS is also used by the American TV network ABC for their Network Alert System (NAS). NAS is a one-way communication system used by ABC to inform and alert their local affiliate stations across the US of information regarding ABC's network programming (such as program timings & changes, news special report information, etc.), using a special decoder manufactured for ABC by EEG Enterprisesbr>
a manufacturer of related equipment for the TV broadcast industry such as

closed captioning Closed captioning (CC) is the process of displaying text on a television, video screen, or other visual display to provide additional or interpretive information, where the viewer is given the choice of whether the text is displayed. Closed cap ...

and general-purpose XDS encoders. The CBS Television Network uses a similar method to transmit three separate internal messaging services to stations: one for programming departments, one for master control operations, and one for newsrooms. Many standard definition receivers produced by

Dish Network DISH Network L.L.C., often referred to as DISH, an abbreviation for Digital Sky Highway, is an American provider of satellite television and IPTV services and wholly owned subsidiary of EchoStar Corporation. The company was originally establ ...

encode XDS data into their output signal. Data encoded includes time of day, program name, program description, program time remaining, channel identification, and content rating. This data is obtained from the satellite service's EPG and replaces any data which may have been present when the signal was uplinked. XDS uses the same line in the

vertical blanking interval In a raster scan display, the vertical blanking interval (VBI), also known as the vertical interval or VBLANK, is the time between the end of the final visible line of a frame or field and the beginning of the first visible line of the next fra ...

(NTSC line 21), and shares the available second video field bandwidth with the closed captioning channels CC3 and CC4, and with the text channels TXT3 and TXT4. XDS information is used by

TV commercial A television advertisement (also called a commercial, spot, break, advert, or ad) is a span of television programming produced and paid for by an organization. It conveys a message promoting, and aiming to market, a product, service or idea. ...

detection software to skip advertisements.

External links

Does anybody really know what time it is?
- Faults & Failures October 2000 IEEE Spectrum - about some failures in the autoclock system in 2000 {{Video formats Television technology Standards of the United States