Abstract: Plural optical communication apparatuses are connected through communication lines with a star topology to an optical coupler that is arranged at the center of star topology and can distribute input light. Each optical communication apparatus makes an optically transmitting unit input an optical signal into an optically inputting unit of the optical coupler, and makes an optically receiving unit receive an optical signal output from an optically outputting unit of the optical coupler, for detecting a collision based on the reception signal. After transmitting an optical signal from the optically transmitting unit, each of optical communication apparatuses makes the optically receiving unit receive the optical signal, performs the collision detection based on the comparison between the transmission signal and the reception signal.

Abstract: Plural optical communication apparatuses are connected through communication lines with a star topology to an optical coupler that is arranged at the center of star topology and can distribute input light. Each optical communication apparatus makes an optically transmitting unit input an optical signal into an optically inputting unit of the optical coupler, and makes an optically receiving unit receive an optical signal output from an optically outputting unit of the optical coupler, for detecting a collision based on the reception signal. After transmitting an optical signal from the optically transmitting unit, each of optical communication apparatuses makes the optically receiving unit receive the optical signal, performs the collision detection based on the comparison between the transmission signal and the reception signal.