Government mandating digital television information
Another demonstration of closed captioning followed at Gallaudet College (now Gallaudet University) on February 15, 1972.
Suddenly, everyone who had been shut out from the world of broadcast media could enjoy television programs along with hearing people.
At the First National Conference on Television for the Hearing Impaired in 1971, two possible technologies for captioning television programs debuted.
Both technologies displayed the captions only on specially equipped sets for deaf and hard-of-hearing viewers.
Galvanized by these successful tests, the Federal Communications Commission (FCC) reserved line 21 for the transmission of closed captions in the United States in 1976.
With the FCC’s approval, PBS engineers innovated the caption editing consoles that would be used to caption prerecorded programs, the encoding equipment that broadcasters and others would use to add captions to their programs, and prototype decoders.
The Bureau wanted to use a portion of the network television signal to send precise time information nationwide, digitally encoding this data in a part of the television signal that didn’t carry picture information.