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 and trade organization composed as an alliance of trade associations for electronics manufacturers in the United States. They devel ...

standard CEA-608-E

for the delivery of any ancillary

data In the pursuit of knowledge, data (; ) is a collection of discrete Value_(semiotics), values that convey information, describing quantity, qualitative property, quality, fact, statistics, other basic units of meaning, or simply sequences of sy ...

( metadata) to be sent with an analog television program, or any other

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 ...

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) sy ...

. 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 ...

TV 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 mi ...

s, and

TV 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, ...

syndication Syndication may refer to: * Broadcast syndication, where individual stations buy programs outside the network system * Print syndication, where individual newspapers or magazines license news articles, columns, or comic strips * Web syndication, ...

distributor A distributor is an enclosed rotating switch used in spark-ignition internal combustion engines that have mechanically timed ignition. The distributor's main function is to route high voltage current from the ignition coil to the spark plug ...

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 continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, ...

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

clock A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and t ...

of newer TVs &

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. ...

s 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 or channel ID or bumper) is the practice of radio and television stations and networks identifying themselves on-air, typically by means of a call sign or brand name (sometimes known, particularly in th ...

, *

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 ...

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) and subtitling are both processes of displaying text on a television, video screen, or other visual display to provide additional or interpretive information. Both are typically used as a transcription of the audio po ...

and general-purpose XDS encoders. The

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 ...

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 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 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 ...

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 In video, a field is one of the many still images which are displayed sequentially to create the impression of motion on the screen. Two fields comprise one video frame. When the fields are displayed on a video monitor they are "interlaced" so th ...

bandwidth with the closed captioning channels CC3 and CC4, and with the text channels TXT3 and TXT4.

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