NTSC

National Television System Committee standard is an analog television broadcast protocol adopted by North America (U.S., Canada, and Mexico) as well as various parts of South America, Japan and a few other key Pacific Rim countries. The system used 525 interlaced lines at 60 Hz. Transmission of NTSC was discontinued in the United States in 2009, although the technology is still in modified use in 1080i and other interlaced formats.