Fujitsu Corporation

Yuzuru Ishioka

Gaku Kimura

Rika Got

Rutsuko Yoshida

An object of the present invention is to propose a method of effecting a protection control for use in a communication network which makes it possible to avoid conflict between a protection switch of a SONET apparatus and a protection switch of an RPR apparatus. To this end, when ring switching of the BLSR is validated, the protection function of the RPR apparatus is invalidated while when the protection function of the RPR apparatus is validated, the ring switching of the BLSR is invalidated. The apparatus of the present invention can be applied to a network in which a ring network formed of a BLSR is connected with an RPR apparatus.

Method of effecting protection control in communication network and RPR apparatus

A communication device which efficiently transports packets through optimal routes. When there are two or more routes to reach a certain destination, a test packet generator generates a test packet for each route, one of them being designated as the reference test packet. A transmission time acquisition unit records the transmission time of each test packet, relative to that of the reference test packet. When a test packet is received, a reception time acquisition unit measures its reception time relative to the reception time of the reference test packet. Calculating the difference between the transmission and reception times and evaluating such difference values for all routes, a transport time evaluation unit ranks the routes in terms of their packet transport times. A packet transmitter selects an appropriate route from the ranked list of possible routes, and sends out packets to the selected route.

Communication device

A remote terminal in an access network where a plurality of exchange and subscriber telephone sets are connected, is provided with an incoming call prohibition control unit for transmitting an incoming call prohibition signal or an incoming call prohibition cancellation signal. The exchange is provided with an incoming call prohibition signal detector unit for receiving the incoming call prohibition signal and the incoming call prohibition cancellation signal, converting the incoming call prohibition signal and the incoming call prohibition cancellation signal to an incoming call prohibition command and an incoming call prohibition cancellation command, respectively, and outputting them to a monitor control unit. The signals from the incoming call prohibition control unit are transmitted to the incoming call prohibition signal detector unit through a transmission line (transmitting apparatus). For a method for transmitting the incoming call prohibition signal or an incoming call prohibition cancellation signal, control messages in a V5.2 interface, tone signals or E1 frame bits can be used.

Subscriber line test system for access network

An optical signal transmission apparatus is disclosed. The apparatus includes an optical signal receiving section receiving a first optical signal through a first optical cable and an optical signal transmitting section transmitting a second optical signal through a second optical cable. The apparatus further includes a control section for stopping the optical signal transmitting section from transmitting the second optical signal when an abnormal condition in the first optical signal is detected.

Optical signal transmission apparatus and method

In a ringer unit driving system for driving a ringer unit provided in common to a plurality of channel units, the ringer unit sends a ringing signal to a communications device via one of the channel units. A signaling bit detection unit, which is provided in each of the channel units, detects a signaling bit contained in a received digital signal applied to one of the channel units and generates a detection signal. A ringer provided in the ringer unit generates the ringing signal. A power source supplies the ringer with power. A switch is connected between the ringer and the power source and is connected to the signaling bit detection unit. The switch connects the power source and the ringer to each other only when the signaling bit detection unit generates the detection signal.

Ringer unit driving system in a subscriber transmission system

A power supply system for an optical network unit in a Fiber In The Loop controls an electric current supplied to optical network units, while maintaining currently established communication channels, by prohibiting establishment of further communication channels. Each of the network units are connected to a plurality of subscriber terminals. A remote terminal is provided with a power supply unit. An electric current is supplied to the optical network units from the power supply unit. A current detecting unit, provided to the power supply unit, detects a current supplied to the optical network units, and outputs a current detection signal when the current supplied to the optical network units exceeds a predetermined level. A line interrupting unit, provided in said remote terminal, interrupts a communication line which is currently not in service when the current detection signal is supplied.

Power supply system for optical network unit of a fiber in the loop

A test system for local subscriber lines, which is used with a telephone communication system having a central office exchange, local subscribers accommodated by the central office exchange, and intervening units, i.e., a central office terminal, a subscriber side remote terminal, and a transmission line connected therebetween. This test system carries out a remote test and a local test independently by using a test line connected between remote test equipment and the remote terminal in which an artificial off-hook creation unit is introduced. This unit is made active when a local test is carried out for each subscriber line, to thereby avoid an occurrence of errors in the remote test.

Growing community of inventors

Kawasaki, Japan

Yuzuru Ishioka