Fujitsu Corporation

Tsutomu Chikazawa

Masahiro Shioda

Koichi Sugama

Ryuji Kayama

Takashi Kaiga

Yukio Katayanagi

Kenichi Yajima

Yutaka Hayama

Kouji Kurihara

Masaaki Iwasaki

Atsushi Suzuki

Atsuki Taniguchi

Hideo Abe

Junichi Moriyama

Yasushi Tateno

Yoshihisa Ikeda

Jun Wakabayashi

Takanori Yasui

Seiji Nakazumi

Noboru Shimizu

Nobuyuki Fukuchi

Toshiyuki Sakamoto

Hiroshi Fukaya

A first transmission device transmits a signal to a third transmission device by using an active line and a spare line. The first transmission device includes a CRC generator and an SN adder. The CRC generator calculates the CRC value of the signal. The SN adder stores, in a FCS byte filed in the signal, the FCS calculated value obtained by adding the SN representing consecutiveness of the signal to the CRC value. Furthermore, the first transmission device outputs the signal in which the FCS calculated value is stored to the second transmission device by using the active line and the spare line.

Transmission device, transmission system, and transmission method

An apparatus for switching multiple communication channels having a redundant configuration, includes a fault determining section configured to determine an occurrence of a fault of data received from a transmitting apparatus via one of the multiple communication channels having the redundant configuration, the data being set with one of multiple classes; a class control section configured to switch the data in one of the multiple classes being determined as having the fault, to one of the multiple communication channels having the redundant configuration being unused for transmission of the data in the class; a switching control section configured to generate switching information including information about the class determined to have the fault and a destination communication channel for the data in the class to be switched to; and a transmission section configured to transmit the switching information to the transmitting apparatus.

Apparatus and method for switching communication channels having redundant configuration

A transmission device in which a bus of a central processing unit is used to synchronize timing signals between units, thereby restraining enlargement in scale of wiring. A reference signal generator generates a reference signal. A reference signal receiver is mounted on a unit set as an active or standby unit and receives the reference signal. A timing signal generator divides the frequency of the received reference signal by means of a frequency divider/counter to generate a timing signal. A count holder holds the count value of the frequency divider/counter. The bus connects the units and the central processing unit. A count receiver receives, via the bus, the count value from the count holder of the active unit. A count updater updates the count value of the frequency divider/counter to the count value received by the count receiver.

Device for synchronizing between an active unit and a standby unit

In a power supply monitoring device, a power supply voltage monitoring portion always monitors a power supply voltage supplied to a monitored circuit and outputs a voltage reduction signal when detecting that the power supply voltage is reduced below a predetermined threshold (e.g. a second voltage higher than a voltage guaranteeing a normal operation of the monitored circuit and lower than a rated voltage). A monitoring controller having received the voltage reduction signal determines whether or not an operational malfunction has occurred in the monitored circuit by comparing operation data of the monitored circuit with reference data of the monitoring controller itself. Also, the monitoring controller executes recovery processing (reset processing or reference data overwrite processing) suitable for the monitored circuit referring to a prestored recovery processing type specific to the monitored circuit when detecting an operational malfunction of the monitored circuit.

Power supply monitoring device

A transmission apparatus to switch a line from a working line to a protection line in the event of a transmission-line failure on the working line. The transmission apparatus includes a classifying unit inputting cross-connect information from an external source and classifying the information into cross-connect categories for each channel; a communication unit gathering the cross-connect categories of each signal-adding or signal-dropping transmission apparatus of a channel and node information identifying the signal-adding or signal-dropping transmission apparatus by communications with an adjacent transmission apparatus for each channel; and a connection-implementation-classifying unit classifying an implementation of a connection between terminals into a corresponding connection category from among connection categories corresponding to a variety of connection implementations in accordance with gathered cross-connect categories of other transmission apparatuses and the cross connect category of the transmission apparatus employed in the station to create a table for executing control to switch a line in the event of failure for each channel.

Transmission apparatus with a function to switch a line in the event of a transmission failure

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 communication device includes a time switch array unit which performs a switching of transmission lines. A switch unit performs a switching connection from a protection channel line among the transmission lines to a working channel line, for each channel formed in the transmission lines. A bridge unit performs a switching connection from a working channel line among the transmission lines to a protection channel line, for each channel formed in the transmission lines. A control unit performs a recovery of a signal transmission on the working channel lines by controlling the switching connections of the switch unit and the bridge unit.

Communication device for switching connection from a working channel

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Kawasaki, Japan

Tsutomu Chikazawa