By law, all television sets manufactured after 1993, with screens of 13 inches or greater, must include a decoder to read captions. For analog television, this is the only requirement. If a set-top box (STB) is being used, the device transmits the closed caption to the TV.
There are several necessary factors for obtaining captions on digital television (DTV). If you use a set-top box (STB), this box must allow the captions to appear on the screen. You must activate this option on your television set. If the STB does not allow captions to appear on the screen, it might be because the box is one that “reads” the caption and sends the image to the television. In this situation, the caption option must be activated on the STB. When buying one of these boxes, make sure that the STB includes at least one of these two options since there are some STBs on the market that do not support the use of captions.
If the DTV signal is received through an antenna, the caption option must be activated on the television menu.