Extended Data Services

XDS (eXtended Data Services), previously known as EDS, is an American standard classfied under EIA standard EIA-766 for the delivery of any auxillary data to be sent with a television program, or NTSC video signal.

XDS is used by tv stations, networks & program syndicators in the USA for several purposes. The most common uses are for time data for automatically setting the clock of newer TV's & VCRs sold in the USA, rudimentary program information which can be displayed on-screen, and V-Chip content advisory data. It is also used for CGMS-A (Copy Generation Management System-Analog) data used by PVRs (Personal Video Recorder) such as TiVO and ReplayTV.

XDS is also used by the American tv network ABC for their NAS (Network Alert System). 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 [1], a manufacturer of related equipment for the TV broadcast industry such as closed captioning encoders.

XDS uses the same line in the VBI as closed captioning (NTSC line 21), but it utilizes the second field (as opposed to closed captioning's line 21, field 1).