Fujitsu Corporation

Yoshihisa Ikeda

Takanori Yasui

Chikashi Hashimoto

Masahiro Shioda

Atsuki Taniguchi

Junichi Moriyama

Hiroyuki Iwaki

Tsutomu Chikazawa

Masato Hashizume

An abnormality in operation is detected by meticulously monitoring the operation of a monitored device that comprises a state machine. The state number, indicating the state the monitored device is currently in, is output from the device. The upper and lower limit values of current consumption is set for each state number. A monitoring circuit, using the upper and lower limit values for the present state number, judges the value of current consumption detected by a current detection circuit and detects whether there is abnormality in operation.

Abnormal circuit operation detection system

In an optical transmission apparatus controlling an optical output portion by a working optical output controller and a protection optical output controller, the optical output controllers separately generate (inverted) preset value signals corresponding to a common output preset value provided from outside, and perform an analog addition of a common optical output monitoring signal and the preset value signal with an integrating circuit. An optical output portion generates an optical output signal which is an optical input signal controlled based on an output of the wired-OR of the optical output controllers, and generates the optical output monitoring signal corresponding to the optical output signal. When the optical output monitoring signal exceeds the preset value signals, the optical output controllers substantially control input terminals of the integrating circuits respectively to a ground potential by using control circuits.

Optical transmission apparatus

An optical transmission technique for a ring transmission system that can transmit time-division-multiplexed optical signals in dual directions. An optical transmitting apparatus comprises a data link reading section, a topology creating section, a data link writing section, a squelch table creating section, a squelch table, an RIP table creating section, an RIP table, a node recognizing section, an east-side receiving unit, an east-side transmitting unit, a west-side transmitting unit, and a west-side receiving unit. When a transmission route is switched at plural positions, the squelch table and the RIP table are automatically created as soon as a crossconnect is set. With minimum setting, the ring transmission system can be normally operated without increasing the number of setting items, the squelch table can be created at a high speed using existing hardware, and an alarm can be automatically transmitted from a secondary node until each table is created.

Optical ring transmission system using squelch method

A line switching method and apparatus for switching multiplex transmission lines to select, for each of channels of transmission data transmitted in the lines, one of the lines in accordance with line alarm information in the transmission data of the channel, have a pointer value detection function, an alarm detection supervision function and a line switching function for time division multiplexed data of digital signals which are processed serially. The line switching apparatus includes a serial processing circuit provided for each line for detecting line alarm information of the channels by serial processing, and a line switching circuit for switching, for the channels, the lines in a time series relationship in response to the results of detection by the serial processing circuits. Each serial processing section includes a pointer frame top position detection circuit for detecting frame top positions of the channels in multiplexed transmission data from pointer information by serial processing, and a line alarm detection circuit for detecting line alarm information of the channels by serial processing in accordance with the results of detection by the pointer frame top position detection circuit.

Growing community of inventors

Yokohama, Japan

Yoshihisa Ikeda