Fujitsu Corporation

Takashi Sekiguchi

Hirofumi Imabayashi

Mitsuo Kaetsu

Shozo Shimada

Noboru Nakama

Yoshihiro Kaneda

Yoshihiro Onoda

Takao Sumiya

The invention relates to an optical transmitting device. Particularly, the invention provides a loss-of-signal detecting device that detects a loss of an optical signal received by a terminal station or a relay station, in the order of an SD and an SF. The loss-of-signal detecting device includes: an optical input unit that outputs received-optical-power reduction information and a LOS alarm based on a measuring of received optical power of an optical input signal; a synchronizing unit that extracts a synchronous clock contained in the optical input signal, and outputs an LOL alarm when the clock is asynchronous; and a loss-of-signal detecting unit that determines the presence or absence of the received-optical-power reduction information, sets the LOS alarm valid based on the output of the LOL alarm when the received-optical-power reduction information is present, and immediately sets the LOS alarm valid when the received-optical-power reduction information is absent, thereby detecting a loss of signal based on a valid LOS alarm.

Loss-of-signal detecting device

A multifan-equipped apparatus in which a plurality of objects mounted are controllably cooled by blowing air using a fan-unit assembly composed of a plurality of fan units. The plural fan units are divided into a plurality of groups; the fan units in the same group are arranged in a queue. And one of the fan units of each group is a master fan unit that is autonomically adjustable in revolutions per minute (rpm) in accordance with a current apparatus-environment temperature and serves to make a tuning control on the rpm of at least one of the remaining fan units in the same group so as to adjust the rpm to a first estimated value corresponding to the autonomic-adjusted rpm of the master fan unit. If an error has occurred in the state of operation of a fan unit of a group as the operation of every fan unit is monitored, the current rpm of the master fan unit of at least one necessary group is set to a second estimated value for a back-up control minimizing a possible loss of cooling performance of the fan-unit assembly due to the occurrence of the error.

Multifan-equipped apparatus for cooling objects mounted at local interior regions and provided with fan-unit assembly and operation monitoring means having an error detector

A cooling apparatus includes a plurality of fan units having a fan respectively, a plurality of temperature sensors detecting temperature of an object of cooling, included in the fan units respectively, and a control portion deciding the speed of the fan according to the temperature detected by the temperature sensors in a self-control mode and increasing the speed of at least one of the other fans when the speed of any one of the fans is lower than a prescribed threshold in a coordinative control mode.

Cooling apparatus and cooling system for realizing efficient cooling

A shelf-type telecommunications device has a back wired board assembly mounted on a back of a shelf unit into which a plurality of plug-in units are inserted side by side. The back wired board assembly has a main back wired board to which at least one plug-in unit is connected and a sub back wired board to which at least one external cable is connected, the outer surface of the main back wired board and the inner surface of the sub back wired board opposing each other. The main back wired board and the sub back wired board are fitted together by using a plurality of relay connectors or pin terminals so as to electrically connect the main back wired board and the sub back wired board to each other without the need for coaxial cables, thus reducing the size of the device.

Growing community of inventors

Kawasaki, Japan

Takashi Sekiguchi