| 摘要 |
PURPOSE: To obtain a telecommunication system which can make simultaneous communication between one terminal and other one or more terminals. CONSTITUTION: In an optical telecommunication system provided with a direct access transmission medium 1, a plurality of terminals 3, 4, 5, and 6 corresponds with each other by using various kinds of optical carriers. In order to enable the third terminal to transmit messages to the first and second terminals while the first and second terminals are connected to each other, each terminal is provided with a modulation circuit 9 and a demodulation circuit 28 for modulating and demodulating data carriers with a subcarrier so that signals from the first and second terminals may be distinguished from the signals from the third terminal. |
