| 摘要 |
PURPOSE:To obtain the similar effect to the case of video telephone set communication in one room by sending a dual tone multi-frequency signal to a control system so as to select a video signal and a sound signal of a conference participant by the intention of participants. CONSTITUTION:Video telephone sets 11, 12,..., 1n of n-sets are in existence and they are connected to n-sets of MODEMs 211, 212,..., 21n of a video telephone conference controller 20 via a public line. A mixed signal comprising a sound signal and a video signal received by each MODEM is separated into the sound signal and the video signal by each of demultiplexer means 221, 222,..., 22n. The sound signal is given to a sound signal matrix conversion circuit 23 and the video signal is given to a video signal matrix conversion circuit 24. The matrix conversion circuits 23, 24 select the connection of lines for video telephone sets under the control of a CPU 25. The sound signal and the video signal selected by the matrix conversion circuits 23, 24 are given to mixer means 261, 262,..., 26n, in which the signals are mixed while being synchronously with each other based on a signal from a synchronization means 27 received via the CPU 25. |
