Hitachi, Ltd.

Hidemasa Narita

Yasuyuki Fukashiro

Koji Takatori

Tetsuya Uda

Masafumi Kamakura

Hiroshi Takeuchi

Kohei Mandai

Masatoshi Shibasaki

Toshiyuki Atsumi

Takao Fukushima

Yukihisa Tamura

A transmission system is provided in a synchronous network, for establishing synchronization with a degree of precision and at a speed being comparable levels as a conventional technique, and further decreasing the probability of out-of-synchronization occurrence. In the present invention, a synchronization signal is detected without performing error correction until synchronization is established, and after the synchronization is established, it is monitored whether or not out-of-synchronization occurs, according to the synchronization signal that has been subjected to the error correction.

Sending apparatus, receiving apparatus, and transmission system

There arises a problem that power consumption increases along with an increasing throughout of an FEC function effective in speeding up of a transmission speed. FEC function information necessary for a system is prepared, and multiple FEC functions are properly used according to a selected transmission line, etc.

Optical communication card and optical transmission device

Multiplexing-technology based large-capacity transmission requires the installation of many types of interface card. In addition, supporting a redundant configuration for preventing data communication from being interrupted requires the devices and cards more than double those required for the production system. An optical communication card includes multiple optical signal transmission/reception units, main signal processing units corresponding to the optical signal transmission/reception units and required for a multiplexed system, and a connection selection unit that can switch among multiple optical transmission lines, and each of the main signal processing units includes multiple function units and a function selection unit.

Optical communication card and communication device

A circuit capable of processing signals of different signal types is provided for identifying the signal type by the signal type setting from an administrator or by the implementation of the optical module, thereby selecting a signal processor to be used. An OTN frame standardized by ITU is used in a fixed manner independent of the signal type to be accommodated, while a corresponding SDH/SONET frame standardized by ITU is used for signal accommodation.

Interface board and optical transmission equipment

Growing community of inventors

Yokohama, Japan

Hidemasa Narita