Abstract: A transmission apparatus includes: a plurality of signal transmission circuits on a transmission path; a monitoring unit that detects a fault by monitoring an operating status of each of the signal transmission circuits; a controlling unit that outputs a reset instruction when the monitoring unit detects the fault; and an individual resetting unit that receives the reset instruction and resets individually each of the signal transmission circuits.

Abstract: A distributed power supply circuit supplying common power to multiple packages in an apparatus so that a primary voltage of the common power is converted into a secondary voltage in a voltage conversion part so as to be supplied to a circuit in each of the packages is disclosed. The distributed power supply circuit includes a power supply monitoring part configured to monitor the primary voltage; a reset part configured to stop the supply of the primary voltage to the voltage conversion part when the power supply monitoring part detects the abnormality of the primary voltage; and a discharge part configured to release a stored charge on the primary side of the voltage conversion part when the power supply monitoring part detects the abnormality of the primary voltage. The power supply monitoring part is separated from the reset part by multiple diodes so as to be provided in parallel with the reset part.

Abstract: A distributed power supply circuit supplying common power to multiple packages in an apparatus so that a primary voltage of the common power is converted into a secondary voltage in a voltage conversion part so as to be supplied to a circuit in each of the packages is disclosed. The distributed power supply circuit includes a power supply monitoring part configured to monitor the primary voltage; a reset part configured to stop the supply of the primary voltage to the voltage conversion part when the power supply monitoring part detects the abnormality of the primary voltage; and a discharge part configured to release a stored charge on the primary side of the voltage conversion part when the power supply monitoring part detects the abnormality of the primary voltage. The power supply monitoring part is separated from the reset part by multiple diodes so as to be provided in parallel with the reset part.

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: A transmission apparatus includes: a plurality of signal transmission circuits on a transmission path; a monitoring unit that detects a fault by monitoring an operating status of each of the signal transmission circuits; a controlling unit that outputs a reset instruction when the monitoring unit detects the fault; and an individual resetting unit that receives the reset instruction and resets individually each of the signal transmission circuits.

Abstract: An optical multiplex communication system includes a transmission part and a receiving part, wherein the transmission part includes a transmission quality detecting part which measures and transmits a transmission quality information for the channels based on a request from the transmission part; the receiving part includes a variable optical attenuation part controls the optical signal level for the channels, an optical level setting part controls the variable optical attenuation part based on a setting value, a setting control part adding the setting value to the optical level setting part based on a request for setting.

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: An optical multiplex communication system includes a transmission part and a receiving part, wherein the transmission part includes a transmission quality detecting part which measures and transmits a transmission quality information for the channels based on a request from the transmission part; the receiving part includes a variable optical attenuation part controls the optical signal level for the channels, an optical level setting part controls the variable optical attenuation part based on a setting value, a setting control part adding the setting value to the optical level setting part based on a request for setting.

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.

Abstract: A format converting system includes a first converter which converts an input signal into N parallel signals (N is an integer). Each of the N parallel signals has a bit rate less than that of the input signal. A latch circuit temporarily latches the N parallel signals in accordance with a clock signal and outputs a plurality of latched signals having a number larger than the N. A selector selectively outputs the latched signals from the latch circuit and stuff bits to be inserted in the N parallel signals in accordance with a control signal so that N parallel output signals having the N parallel signal and the stuff bits are output from the selector. The stuff bits are used for converting a frame format of the input signal into a different frame format.