Why do captions sometimes disappear during commercial breaks?
When a program is being captioned live and reaches a commercial break or the end of the program, the captioner must send a command to enable the encoder that is processing the captions to accept other data. If the captioner neglects to send this enabling command when finishing the captioning of a segment or program, the captions on the next commercial or program will not be able to access the encoder, and will not appear. The technical staff at the broadcast site must be alert for this situation. Also, the commercials themselves might not be captioned.