In 1941, the first NTSC standard was introduced by the National Television System Committee. This standard defined a transmission scheme for a black and white picture with 525 lines of vertical resolution at 60 fields per second. In the early 1950s, this standard was superseded by a backwards-compatible standard for color television. The NTSC standard was exclusively being used in the Americas as well as Japan until the introduction of digital terrestrial television (DTT). While Mexico have ended all its analogue television broadcasts and the US and Canada have shut down nearly all of their analogue TV stations, the NTSC standard continues to be used in the rest of Latin American countries except for Argentina, Paraguay and Uruguay where PAL-N standard is used, while testing their DTT platform.