To transmit additional information to a terminal even if a space does not exist in a transmission band.
When a communication service unit 1 is connected to the respective communication terminals 3, it temporarily stops the transmission of communication information before the transmission of communication information including a video, sound and data, which are transmitted for the original purpose of communication or during the communication of communication information, or transmits additional information accumulated in an additional information accumulation part 2 after the completion of the transmission of communication information which is the original purpose of communication when the communication of communication information is terminated. A communication service unit 1-side reduces the transmission band of communication information or sends an instruction from the communication service unit 1 to the communication terminal 3 being a communication information transmission source. A communication terminal 3-side reduces the transmission band of communication information and reduces temporarily the transmission rate of communication information or during communication from the first to the last. Thus, information can be transmitted while the transmission band of communication information, which is set at first, is secured.
MURAYAMA OSAMU
HORII YUJI
OKA SUSUMU
