In a domestic television market where 9 million sets are sold annually, whether these figures are low or high can be debated either way. DBS digital broadcasting is a revolutionary event in Japanese broadcasting history, more significant even than the switch from black and white to color broadcasting in the 1960s. DBS digital broadcasting uses the BSAT-5 satellite built by the American firm Orbital Science. Satellite broadcasts are regulated by the International Telecommunication Union, which allocates each country certain frequencies and relays. Programming can also only be broadcast within domestic borders.
Japan is allotted four relays and eight channels.
Eight broadcasting companies are involved in Japan's digital DBS television. Japan, on the other hand, limits the number of recognized formats to five. These formats will be for both surface wave digital broadcasts, scheduled to begin in 2003, and CS digital broadcasts using communications satellites. With the interlace scanning mode, the effective scanning lines are divided into even and odd numbers and shown on the screen alternately. In the progressive scanning mode, all scanning lines are shown simultaneously.