Abstract: A transmission device includes a receiver receiving a signal transmission frame from a network, where a client signal is mapped to the signal transmission frame; a separator separating the client signal from the signal transmission frame; a phase synchronizer generating a clock based on a frequency adjustment information set of the client information included in the signal transmission frame; a transmitter transmitting the client signal to a client transmission path by using the clock generated by the phase synchronizer; a memory storing the frequency adjustment information set included in the signal transmission frame in response to receiving the signal transmission frame from the network by the receiver; and a switch controller causing the phase synchronizer to generate a clock based on the frequency adjustment information set stored in the memory in response to not receiving the signal transmission frame from the network by the receiver.

Abstract: The light transmitting and receiving module includes a light outputting section; alight receiver which receives input light and which outputs an electric signal having an intensity corresponding to a light intensity of the input light; a first variably attenuation controller which variably attenuates the light output from the light outputting section; a second variably attenuation controller which variably attenuates the input light to the light receiver; a first switch which selectively switches a path through which the light from the first variably attenuation controller is output between a light transmitting path and an alternative path different from the light transmitting path; and a second switch which selectively switches light to be output to the second variably attenuation controller between light from an external entity and the light through the alternative path of the first switch.

Abstract: A transmission device includes a receiver receiving a signal transmission frame from a network, where a client signal is mapped to the signal transmission frame; a separator separating the client signal from the signal transmission frame; a phase synchronizer generating a clock based on a frequency adjustment information set of the client information included in the signal transmission frame; a transmitter transmitting the client signal to a client transmission path by using the clock generated by the phase synchronizer; a memory storing the frequency adjustment information set included in the signal transmission frame in response to receiving the signal transmission frame from the network by the receiver; and a switch controller causing the phase synchronizer to generate a clock based on the frequency adjustment information set stored in the memory in response to not receiving the signal transmission frame from the network by the receiver.

Abstract: The light transmitting and receiving module includes a light outputting section; alight receiver which receives input light and which outputs an electric signal having an intensity corresponding to a light intensity of the input light; a first variably attenuation controller which variably attenuates the light output from the light outputting section; a second variably attenuation controller which variably attenuates the input light to the light receiver; a first switch which selectively switches a path through which the light from the first variably attenuation controller is output between a light transmitting path and an alternative path different from the light transmitting path; and a second switch which selectively switches light to be output to the second variably attenuation controller between light from an external entity and the light through the alternative path of the first switch.

Abstract: A feedback control device capable of continuously performing high-accuracy, stable control even in cases where any of multiple controllers for controlling a controlled system becomes incapable of control action. A controller (master controller) generates control data for stably controlling a heater by feedback control, controls the heater in accordance with the control data, and sends the control data to the other controller (slave controller). The slave controller receives the control data from the master controller but does not control the heater while the master controller is operating normally. If the master controller develops anomaly and becomes incapable of normal control action, the slave controller initiates feedback control of the heater in accordance with the control data received from the master controller immediately before the anomaly occurred, and controls the heater thereafter in accordance with control data generated thereby.

Abstract: An optical communication device for detecting a defect in a standby optical fiber. An active optical output unit converts an electrical signal to an optical signal, and a standby optical output unit is provided as a substitute for the active optical output unit. An optical router is connected to the active optical output unit by an active optical fiber, and is also connected to the standby optical output unit by a standby optical fiber. The optical router outputs the optical signal received from the active optical output unit to the subsequent stage, and also outputs part of the optical signal to the standby optical output unit. A defect detector detects a defect in the standby optical fiber on the basis of the light level of the optical signal output from the optical router to the standby optical output unit through the standby optical fiber.

Abstract: When switching over of a first optical transmitting section and a second optical transmitting section is performed, a monitor signal from a monitor section of each of the first optical transmitting section and the second optical transmitting section is supervised. Then, on the basis of each of the monitor signal, an optical switch section provided in each of the first optical transmitting section and the second optical transmitting section is controlled, and an optical level adjusting section provided in each of the first optical transmitting section and the second optical transmitting section is controlled.

Abstract: A feedback control device capable of continuously performing high-accuracy, stable control even in cases where any of multiple controllers for controlling a controlled system becomes incapable of control action. A controller (master controller) generates control data for stably controlling a heater by feedback control, controls the heater in accordance with the control data, and sends the control data to the other controller (slave controller). The slave controller receives the control data from the master controller but does not control the heater while the master controller is operating normally. If the master controller develops anomaly and becomes incapable of normal control action, the slave controller initiates feedback control of the heater in accordance with the control data received from the master controller immediately before the anomaly occurred, and controls the heater thereafter in accordance with control data generated thereby.

Abstract: An optical communication device for detecting a defect in a standby optical fiber. An active optical output unit converts an electrical signal to an optical signal, and a standby optical output unit is provided as a substitute for the active optical output unit. An optical router is connected to the active optical output unit by an active optical fiber, and is also connected to the standby optical output unit by a standby optical fiber. The optical router outputs the optical signal received from the active optical output unit to the subsequent stage, and also outputs part of the optical signal to the standby optical output unit. A defect detector detects a defect in the standby optical fiber on the basis of the light level of the optical signal output from the optical router to the standby optical output unit through the standby optical fiber.