Patent ID: 7016612

Claim:
A digital optical communication device comprising: an optical reception circuit converting an optical signal received from any external source to an electric signal; a decoding circuit decoding the electric signal resultant from conversion by said optical reception circuit and judging whether or not the decoding is normally completed; a reception light intensity level judgement circuit judging an intensity level of received light based on the electric signal resultant from conversion by said optical reception circuit; a coding circuit coding transmission data; an optical transmission circuit being configured to determine a light emission intensity based on result of the judgement by said reception light intensity level judgement circuit and result of the judgement by said decoding circuit and to convert the transmission data coded by said coding circuit to an optical signal with the light emission intensity; wherein said optical transmission circuit determines the light emission intensity from a plurality of different light emission intensity values by referring to the intensity level judged by said reception light intensity level judgement circuit in the case where said decoding circuit judges that the decoding is normally completed, where said plurality of different light emission intensity values each correspond to a different range of reception light intensities; and wherein said optical transmission circuit determines the light emission intensity without referring to the intensity level judged by said reception light intensity level judgement circuit in the case where if said decoding circuit judges that the decoding is not normally completed.