Hitachi, Ltd.

Nippon Telegraph and Telephone Corporation

Nippon Kokan Kabushiki Kaisha

Hitachi Communication Technologies, Ltd.

Hitachi Hokkai Semiconductor Ltd.

Takashi Mori

Masaki Ohira

Yukio Nakano

Toshiki Sugawara

Masahiro Takatori

Hideaki Tsushima

Yasuyuki Fukashiro

Sunao Kakizaki

Masatoshi Takahashi

Yusuke Yajima

Shigeki Kitajima

Masatoshi Shibasaki

Mitsunobu Kimura

Yoshihiro Ashi

Shinobu Gohara

Koji Kato

Tadayuki Kanno

Munetoshi Tsuge

Masanobu Kobayashi

Kazutaka Sakai

Atsushi Kubotera

Masazumi Noguchi

Yoshio Miyamori

Hiroshi Kikuchi

Hiroyuki Nakano

Takeo Yamada

Akihiko Takase

Yukio Hayashi

Tetsuya Hayashida

Tetsuya Uda

Junichirou Yanagi

Hiromi Ueda

Tooru Hirai

Keiji Usuba

Sanseki Moriguchi

Gyoichi Suzuki

Shinichi Kuwano

Toshihiko Satoh

Yasuo Okuyama

Takashi Miyazu

Mitsutoshi Miura

Keiichi Ishida

Mamoru Yanagiuchi

Masahiro Muroya

Seigo Obayashi

An OLT transmits and receives a CMTS/CM apparatus control signal through an apparatus physical management interface which is physically identical to or different from a main signal interface (NNI) and processes the CMTS apparatus control signal by itself. When connection of a new ONU is detected by an ONU apparatus control signal, an IP address is allocated by using the CM apparatus control signal in a manner similar to the CM. The CM apparatus control signal regarding the ONU is transmitted and received by using the IP address and a mutual conversion is performed between the CM apparatus control signal and the ONU apparatus control signal. The ONU processes the ONU apparatus control signal in a manner similar to the ONU based on an ordinary PON standard.

Communication system using passive optical network and passive optical network

In a known wavelength multiplexer, optical signals to pass are passed with their wavelengths held identical. Therefore, unless an unused wavelength common to all zones exists in case of setting an optical channel, the channel cannot be set. According to the present invention, a drop/add type wavelength multiplexer includes a wavelength converting section (in FIG.) which converts the wavelengths of optical signals to pass from the input side of the multiplexer to the output side thereof. In a network employing the wavelength multiplexers at individual nodes, a new optical channel can be easily set by utilizing wavelengths not used at the nodes.

Optical multiple transmission method, optical network and optical transmission apparatus

A client signal having a constant bit rate is segmented every a bytes to create code information blocks. The bit rate of the client signal is increased such that the client signal has the code information block and an empty area comprised of b bytes, and the ratio c/a is equal to or higher than 110% to create a code blockcomprised of c bytes. The code information block in the code block is encoded such that an error correcting code is included therein to have an encoding gain of 6 dB or higher for a bit error ratio of 10. Associated check bits are placed in the empty area to eventually generate a super FEC signal.

Method for encoding/decoding error correcting code, transmitting apparatus and network

An optical switch having plural input terminals and plural output terminal, plural dispersion compensators, and a controller for monitoring the change-over state of the optical switch and the dispersion compensation quantities of the plural dispersion compensators and controlling the setting of the optical switch are provided. In response to a request for setting dispersion compensation, the optical switch is set according to the dispersion compensation quantity of each dispersion compensator and the change-over state of the optical switch.

Variable dispersion compensation equipment, optical transmission system using it and method of setting dispersion compensation quantity

An overhead passing processing circuit in a synchronous multiplex network, with a circuit for extracting predetermined administration and maintenance operating information from multiplexed signals, a crossconnecting circuit for crossconnecting information extracted by the extraction circuit stage, and an insertion circuit for inserting an output of the crossconnecting circuit into a predetermined location in the overhead of the multiplexed signal to be transmitted.

Multiplex transmission apparatuses, multiplex transmission networks, and operation method therefor

In a transmission network including multiplex transmission units A, F, G, D and E, when the line breakage has occurred on the OC-12 transmission path of the direction from unit A to unit F, the unit F detects the signal coming in from the OC-12 path indicative of the line breakage. The unit F inserts the APS bytes which comes in from the unit A into the undefined area of the OC-192 transport overhead which is reserved for the through-transport of APS bytes, and transports it to the unit G. On receiving the through-transport APS bytes, the unit G inserts it intact into the defined area for the APS bytes in the OC-12 transport overhead, and sends it to the unit D. In this manner, protection switching between the units A and D is carried out.

Method and apparatus for multiplex transmission

In an optical switching apparatus having redundantly-arranged optical switches, a route switching operation mode, an autonomic redundant switching operation mode and a compulsory redundant switching operation mode are discriminated from one another so that these operation modes are prevented from being executed at the same time, and also proper mask processing is performed at every switching operation mode. Therefore, emission of an undesired alarm and thus occurrence of malfunction when each switching operation is carried out can be prevented.

Optical switching apparatus, optical transmission system and method of setting up for optical signal route

An optical one-to-one protection switching apparatus exchanges signals between a transmit node and a receive node. If a fault is detected in the first transmission line (down-stream), a controller in the node controls a drive circuit so as to shut off a gate. Then, the controller in the transmit node upon receiving a switching request from the receive node, controls the drive circuit so as to shut off the gate. Thereby, the optical switch is switched. The transmitter of the client terminal is thus connected to the second transmission line (down-stream). Upon receiving the switching request from the transmit node, the optical switch in the receive node is switched. Thereby the receiver in the client terminal is connected to the second transmission line (down-stream).

Optical one-to-one protection switching apparatus

An encoder adds an identifier, being different when the coding should be done or not, into a predetermined location in an original signal, while a decoder reads out the identifier added and detects the condition of coding, so as to decide the execution (ON) of the decoding process to be done or not, automatically. Further, in each of the encoder and the decoder, there is provided a delay output portion, which provides an output treated with only a specific delay but not executing the coding/decoding thereon, separately from a coding process portion or a decoding process portion, wherein a selection can be made, at which one of the signals from the respective process portions and the delay output portion should be outputted, by a setup in an outside operation system with use of a selector.

Forward error correcting code encoding equipment, forward error correcting code decoding equipment, and transmission apparatus

An encoder adds an identifier, being different when the coding should be done or not, into a predetermined location in, an original signal, while a decoder reads out the identifier added and detects the condition of coding, so as to decide the execution (ON) of the decoding process to be done or not, automatically. Further, in each of the encoder and the decoder, there is provided a delay output portion, which provides an output treated with only a specific delay but not executing the coding/decoding thereon, separately from a coding process portion or a decoding process portion, wherein a selection can be made, at which one of the signals from the respective process portions and the delay output portion should be outputted, by a setup in an outside operation system with use of a selector.

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Yokohama, Japan

Takashi Mori