Abstract: An optical signal adjustment apparatus detects an optical signal intensity level of signal light components with multiple different wavelengths for each of the wavelengths in an optical detection unit and adjusts the signal light components with the wavelengths for each of the wavelengths in a variable optical attenuator to make the optical signal intensity levels of the signal light components uniform. The apparatus includes a control unit configured to successively select a detection signal associated with each of the wavelengths from the optical detection unit and generate a control signal for the wavelength based on the selected detection signal. The control signal generated by the control unit is supplied to the variable optical attenuator associated with the selected detection signal.

Abstract: An optical signal adjustment apparatus detects an optical signal intensity level of signal light components with multiple different wavelengths for each of the wavelengths in an optical detection unit and adjusts the signal light components with the wavelengths for each of the wavelengths in a variable optical attenuator to make the optical signal intensity levels of the signal light components uniform. The apparatus includes a control unit configured to successively select a detection signal associated with each of the wavelengths from the optical detection unit and generate a control signal for the wavelength based on the selected detection signal. The control signal generated by the control unit is supplied to the variable optical attenuator associated with the selected detection signal.

Abstract: A redundant changeover apparatus causing no frame synchronization loss even upon occurrence of changeover between working system and protection system. In case of an in-apparatus synchronization system, when two input signals which are mutually asynchronous in phase are changed over by a changeover switch, a changeover switch, a clock extractor, a PLL circuit, and a clock changing portion transmit signals with clocks before the changeover being gradually changed to clocks after the changeover. Alternatively, in case of an in-apparatus synchronize system, data are separated from clocks so that the data are once changed to data with reference clocks, and then for the data, clocks before the changeover are gradually changed to clocks after the changeover.

Abstract: In a method and an apparatus for determining characteristic deterioration in an individual device, an initial status value of the device is stored, preferably per temperature, a present status value of the device in operation is stored preferably corresponding to the temperature, the initial status value and the present status value are read corresponding to the temperature to normalize the present status value with the initial status value, and it is determined whether or not the normalized value is within a normal range.

Abstract: An optical transmission device in which optical signal switching is performed to allow the device to be reduced in size and also which is capable of efficient recovery from fault, thereby improving system expansibility and communication quality. Overhead terminating section converts an optical signal to an electric signal and performs an overhead process including extraction of fault information and setting of status information. Optical switch section performs a process of switching the optical signal between active and standby lines, and switching control section provides a switching command to the optical switch section in accordance with the fault information.

Abstract: The present invention provides a receiver apparatus for receiving digital data in which stuff data have been inserted by stuffing synchronization. The receiver apparatus has a memory unit having a plurality of memory cells. The digital data other than the stuff data are written in the memory unit in synchronization with a write clock signal, and read from the memory cell in synchronization with a read clock signal. The cycle of the read clock signal is adjusted on the basis of an interval from a reading address to an writing address of the memory cell.

Abstract: A communication apparatus for interfacing various types of signals with different bit-rates is provided. The communication apparatus includes a receiving part receiving input signals, generating frames of a predetermined common format containing control information of the input signals and determining whether the frames are valid and a control part receiving the frames from the receiving part and performing a predetermined internal process based on the result of the determination.

Abstract: A redundant changeover apparatus causing no frame synchronization loss even upon occurrence of changeover between working system and protection system. In case of an in-apparatus synchronization system, when two input signals which are mutually asynchronous in phase are changed over by a changeover switch, a changeover switch, a clock extractor, a PLL circuit, and a clock changing portion transmit signals with clocks before the changeover being gradually changed to clocks after the changeover. Alternatively, in case of an in-apparatus synchronize system, data are separated from clocks so that the data are once changed to data with reference clocks, and then for the data, clocks before the changeover are gradually changed to clocks after the changeover.

Abstract: An optical transmission unit and optical transmission system which have more efficient failure recovery functions to provide improved communication services, without increasing the size of network equipment. A control channel manager manages a control channel, as well as a control channel signal on that channel, for the purpose of failure recovery of optical signal transport. An optical switch fabric switches optical signal paths to perform protection switching between working facilities and protection facilities. A protection switching controller sends a switching command to the optical switch fabric, based on the information provided through the control channel.

Abstract: An optical transmission device in which optical signal switching is performed to allow the device to be reduced in size and also which is capable of efficient recovery from fault, thereby improving system expansibility and communication quality. Overhead terminating section converts an optical signal to an electric signal and performs an overhead process including extraction of fault information and setting of status information. Optical switch section performs a process of switching the optical signal between active and standby lines, and switching control section provides a switching command to the optical switch section in accordance with the fault information.