525-line (or EIA 525/60) is an American standard-definition television resolution used since July 1, 1941,[1][2][3] mainly in the context of analog TV broadcast systems.
It consists of a 525-line raster, with 486 lines carrying the visible image at 30 (29.97 with color) interlaced frames per second.
It was eventually adopted by countries using 60 Hz utility frequency as TV broadcasts resumed after World War II.
A similar 625-line system was adopted by countries using 50 Hz utility frequency.
[5] The following International Telecommunication Union standards use 525-lines: The following analog television color systems were used in conjunction with the previous standards (identified by a letter after the color system indication): 525-lines is sometimes mentioned when digitizing analog video, or when outputting digital video in a standard definition analog compatible format.