EIA-608
EIA-608, also known as line 21 captions and CEA-608, used to be the standard for closed captioning for NTSC TV broadcasts in the United States, Canada and Mexico. It also specifies a Extended Data Service, which is a means for including a VCR control service with a now/next EPG for NTSC transmissions that operates on the even line 21 field, similar to the TeleText based VPS that operates on line 16 which is used in PAL countries.
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