PURPOSE: To constitute easily a system of an optional size by providing a coupling device connecting among star couplers and relaying/sending an optical signal from a terminal equipment and applying the transmission control of an optical signal by the terminal equipment according to the carrier detection multiplex access collision detection system.
CONSTITUTION: When a transmission request takes place in a terminal equipment 11 and other terminal equipments 12∼14 are not in transmission, the terminal equipment 11 starts the transmission. The transmission optical signal is branched by the star coupler 15 and sent to own terminal equipments 11, 12 and a coupler 17. The transmission terminal equipment 11 uses the returned optical signal to detect collision and when the collision detection at other terminal equipment, the transmission is stopped and retransmission is operated after a prescribed time. The coupler 17 amplifies the optical signal attenuated by the star coupler 15 so as to be the same intensity as the direct transmission to the star coupler 16 by the terminal equipments 11, 12 and the result is fed to the star coupler 16. Thus, the coupler 17 is a kind of a terminal equipment when viewed from the star coupler 16. This is applied to the case that the coupler 17 is viewed from the star coupler 15.
OKADA AKIHIRO
MATSUDA TAKASHI
