Patent ID: 7493043

Claim:
An optical line termination in a passive optical network system in which each of one or plural first optical network units at user side and the optical line termination at station side are connected to each other through an optical fiber and a splitter, and communication is performed in accordance with an identifier assigned to each of the first optical network units connected to the optical line termination, the optical line termination comprising: a first storage area in which unique numbers of the first optical network units and individual setting information concerning communication and/or users of the first optical network units are stored correspondingly to the identifier of the first optical network unit; a second storage area in which the unique number of the first optical network unit which is specified as a replacement object from among the first optical network units is stored correspondingly to the identifier; and a processing unit to perform a processing to replace one of the connected first optical network units by a second optical network unit, wherein the processing unit receives a replacement instruction including the identifier of the first optical network unit specified as the replacement object from an operation system, acquires the unique number of the first optical network unit corresponding to the specified identifier from the first storage area, and stores the acquired unique number of the first optical network unit into the second storage area correspondingly to the specified identifier, deletes the unique number corresponding to the specified identifier from the first storage area, acquires the unique number of the first optical network unit or a unique number of the second optical network unit newly connected instead of the first optical network unit, judges whether the acquired unique number is stored in the second storage area, stores, in a case where the unique number of the second optical network unit is acquired thereby being judged that the acquired unique number is not stored in the second storage area, the acquired unique number into the first storage area correspondingly to the specified identifier; and repeats, in a case where the unique number of the first optical network unit is acquired thereby being judged that the acquired unique number is stored in the second storage area, the acquiring the unique number of the first or the second optical network unit, the judging and the storing into the first storage area.