: It was originally designed for closed-circuit television (CCTV) and military displays.
In broadcasting, is a specific ATSC Standard that defines how captions and subtitles are handled in modern digital television. 343 mp4
: It is often referenced in the context of H.264/MP4 encoding hardware designed to capture and compress old analog RS-343 signals into digital formats. 3. ATSC Standard A/343 : It was originally designed for closed-circuit television