Data transmission system for broadcast distribution in a CATV system.

摘要

In a data transmission system 1, a center 3 and a plurality of terminals 5 are connected by a coaxial cable 7. The center 3 is controlled by a server 11 to transmit mode sense polling signals in succession every predetermined time (for example every 30 seconds) to all of the karaoke terminals 5 connected to the center 3. The center 3 determines whether each terminal 5 is in a karaoke mode or not based on the mode response signal transmitted from each terminal 5 in response to the mode sense polling signals. The center 3 then transmits request polling signal only to terminals 5 determined as being in the karaoke mode, confirms whether a request for a song has been made, and transmits karaoke data to those terminals that have a request.