Patent ID: 8467684

Claim:
A station side communication device connected to a plurality of subscriber side communication devices via a light multiplex/demultiplex device and deciding an order of optical signal transmissions from the subscriber side communication devices and deciding and instructing a transmission start timing for starting transmission of an optical signal for each of the subscriber side communication devices, the station side communication device comprising: an optical signal monitor unit which monitors powers of optical signals received from the subscriber side communication devices; a transmission time adjusting unit which, based on a power of an optical signal of a first of said subscriber side communication devices that is monitored by said optical signal monitor unit, decides as to how long a length of transmission interval is to be placed before a second of said subscriber side communication devices that will transmit an optical signal next after said first subscriber side communication device, starts to transmit the optical signal, after completion of optical signal transmission by said first subscriber side communication device; and a transmission permission unit which decides the transmission start timing of the second subscriber side communication device by using the transmission interval decided by the transmission time adjusting unit.