| 摘要 |
PROBLEM TO BE SOLVED: To shorten a polling waiting time of terminal transmission in emergency by transmitting an incoming message of the length shorter than a minimum outgoing message length from a transmission starting time of an outgoing time from a center device by having a transmitter use a transmission start monitoring means in emergency. SOLUTION: A head end C has a video signal of an autonomy broadcasting or a TV broadcasting and a data signal sent to a transmission line E by using an outgoing channel by way of a mixer. Customer side terminals F1 to Fm provided in the transmission line E have the data signal transmit to the transmission line E by using an incoming channel. In such a CATV system, terminals Z1 to Zm in emergency use a transmission start monitoring means for monitoring a transmission start time of the outgoing message from the center device and transmits the incoming message of the length below the minimum outgoing message length as soon as transmission of the outgoing message is started to the center device. |
