Extended Data Services (now XDS, previously EDS), is an American standard classified under Electronic Industries Alliance standard CEA-608-E for the delivery of any ancillary data (metadata) to be sent with an analog television program, or any other NTSC video signal.
XDS is used by TV stations, TV networks, and TV program syndication distributors in the USA for several purposes.
Here are some of the most common uses of XDS:
- The "autoclock" system delivers time data via an XDS "Time-of-Day Packet" for automatically setting the clock of newer TVs & VCRs sold in the USA. Most PBS 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,
- V-chip content ratings 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 USA 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 Enterprises, a manufacturer of related equipment for the TV broadcast industry such as closed captioning 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.
XDS uses the same line in the vertical blanking interval as closed captioning (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.
Famous quotes containing the words extended, data and/or services:
“Only very slowly and late have men come to realize that unless freedom is universal it is only extended privilege.”
—Christopher Hill (b. 1912)
“Mental health data from the 1950’s on middle-aged women showed them to be a particularly distressed group, vulnerable to depression and feelings of uselessness. This isn’t surprising. If society tells you that your main role is to be attractive to men and you are getting crow’s feet, and to be a mother to children and yours are leaving home, no wonder you are distressed.”
—Grace Baruch (20th century)
“O, the difference of man and man!
To thee a woman’s services are due.”
—William Shakespeare (1564–1616)