Fujitsu Corporation

Takashi Sakata

Eisaku Touma

Takahiro Aramaki

Noboru Iwabuchi

Takashi Kawakami

An IP encapsulator in a broadcast distributing system divides broadcast data received from an image distributing source into packets, and IP-encapsulates the packets. The IP encapsulator transmits the IP-encapsulated packets to a subscriber line terminal (SLT) via a network. The SLT includes a memory that stores therein broadcast data, and performs TOS control and transfer-route switching control based on memory occupancy of the SLT.

Broadcast distributing system and broadcast distributing method

The optical communication system employs PON system. An office device includes a pair of an optical transmitting/receiving devices. A subscriber line, which is a single core optical fiber, is connected to the optical transmitting/receiving devices at each terminal to form a loop network. Subscriber devices are connected to the network via passive optical branching/coupling elements. When the office device transmits a test signal, the subscriber devices transmit response signals corresponding to the test signal. The office device specifies fault point based on the response signals received by the optical transmitting/receiving devices.

Optical communication system

In an optical subscriber network system which connects plural optical network units to an optical service unit using passive optical elements through an optical transmission line, the optical transmission line is duplexed with a lower cost. The optical service unit and the optical network units each have plural transmission-reception portions the wavelengths of which are different from each other, and the inputs and outputs of the plural transmission-reception portions are multiplexed with the wavelengths (WDM) into a single optical transmission line to form a pseudo redundant communication path between the optical service unit and the optical network units. The communication which uses a certain wavelength between the optical service unit and the optical network units is active, and the communication which uses another wavelength is a standby. When the active communication has a fault, a switchover operation to the standby communication is performed. The communication path using plural wavelengths between the optical service unit and the optical network units can select either the function of &ldquo;with redundancy&rdquo; or &ldquo;without redundancy&rdquo; or &ldquo;enhanced line speed&rdquo;, depending on subscribers' demands.

Optical subscriber network system

The invention provides an optical subscriber network system which can secure dual construction of optical transmission/reception sections of optical network units, specification of a failed faulty point in optical transmission lines and reception circuits of the optical network units and regular timing transmission of upstream data. The optical subscriber network system has a passive optical network construction wherein a plurality of network units are accommodated in a station apparatus through an optical transmission line using a passive optical element, and includes bypass transmission lines for mutual supervision control between the network units. A network unit mutual supervision control signal is communicated between the network units through the bypass transmission lines. The network unit mutual supervision control information received by each of the network units is transmitted to the station apparatus through the optical transmission line so that a fault is supervised based on the network unit mutual supervision control information by the station apparatus.

Growing community of inventors

Kawasaki, Japan

Takashi Sakata