Wansegu (1seg)

1seg (ワンセグ wansegu^?) is a mobile terrestrial digital audio/video and data broadcasting service in Japan, Argentina, Brazil, Chile, Uruguay and Peru.

Service began experimentally during 2005 and commercially on April 1, 2006. In Brazil, the broadcast started in late 2007 in just a few cities, with a slight difference from Japanese 1seg: a 30 frame/s transmission, while in Japan they use a 15 frame/s transmission.

The first mobile phone handsets for 1seg were sold by KDDI to consumers in autumn 2005.

ISDB-T, the terrestrial digital broadcast system used in Japan, Argentina, Brazil, Chile, Peru and Uruguay, is designed so that each channel is divided into 13 segments, with a further segment separating it from the next channel. An HDTV broadcast signal occupies 12 segments, leaving the remaining (13th) segment for mobile receivers. Thus the name, "1seg" or "One Seg".