Patent ID: 8200088

Claim:
A communication unit used in an optical communication system including: a first upper apparatus and a second upper apparatus that communicate with each other by an optical signal in a first optical transmission scheme; the communication unit that is located downstream from the first upper apparatus and communicates with the first upper apparatus; an another communication unit that is located downstream from the second upper apparatus and communicates with the second upper apparatus; a first terminal that is located downstream from the communication unit; and a second terminal that is located downstream from the another communication unit, the first terminal and the second terminal communicate with each other by an optical signal in a second optical transmission scheme through the communication unit, the first upper apparatus, the second upper apparatus, and the another communication unit, the communication unit comprising: a first terminator operable to terminate a communication channel in the first optical communication scheme between the communication unit and the another communication unit through the first upper apparatus and the second upper apparatus; a second terminator operable to terminate the optical signal in the second optical communication scheme; a switch which selectively switches between a first setting in which a first optical signal in the second optical communication scheme between the communication unit and the first terminal is terminated at the second terminator and a second optical signal in the second optical communication scheme between the communication unit and the second terminal connected through the communication channel in the first optical communication scheme via the first terminator is terminated at the second terminator and a second setting in which the first optical signal in the second optical communication scheme between the communication unit and the first terminal is output through the communication channel in the first optical communication scheme to be terminated at the another communication unit and the second optical signal in the second optical communication scheme input from the another communication unit through the communication channel in the first optical communication scheme via the first terminator skips a termination process performed by the second terminator and is output to the first terminal.