FCC documentation reads: “… [all new] television receivers must contain circuitry to decode and display closed captioning.” Further, “Decoders must support the eight fonts listed in EIA-708. Caption providers may specify 1 of these 8 font styles to be used to write caption text. Decoders must include the ability for consumers to choose among the eight fonts. The decoder must display the font chosen by the caption provider unless the viewer chooses a different font.”
For complete guidelines on the FCC requirements please visit the FCC website.