Abstract: A transmission device in which a bus of a central processing unit is used to synchronize timing signals between units, thereby restraining enlargement in scale of wiring. A reference signal generator generates a reference signal. A reference signal receiver is mounted on a unit set as an active or standby unit and receives the reference signal. A timing signal generator divides the frequency of the received reference signal by means of a frequency divider/counter to generate a timing signal. A count holder holds the count value of the frequency divider/counter. The bus connects the units and the central processing unit. A count receiver receives, via the bus, the count value from the count holder of the active unit. A count updater updates the count value of the frequency divider/counter to the count value received by the count receiver.

Abstract: A plug-in card for an optical transmission apparatus includes a J1generating unit. The J1 generating unit sends information on on-use side J1 data to a plug-in card at a spare side in a redundant structure when the plug-in card operates as an on-use side plug-in card. The J1 generating unit receives information on on-use side J1 data from a plug-in card at the on-use side when the plug-in card operates as a spare side plug-in card. Based on the information, the J1 generating unit matches spare side J1 data to the on-use side J1 data. The plug-in card also includes a B3 byte calculating unit that operates in a similar way as the J1 generating unit does in processing B3 byte data.

Abstract: An object of the invention is to provide a diagnosis method for standby systems in an optical ring network having a redundant configuration, which can confirm normal states of standby systems in all optical transmission apparatuses on the network, even during operations of active systems. To this end, in the present diagnosis method for standby systems, when a diagnosis start command is given to an arbitrary optical transmission apparatus on the network, the optical transmission apparatus provides a false signal to a standby system unit to diagnoses an operation state thereof, and transmits the result to the optical transmission apparatus on the downstream side by utilizing overhead information in the active system optical channel.

Abstract: A transmission device in which a bus of a central processing unit is used to synchronize timing signals between units, thereby restraining enlargement in scale of wiring. A reference signal generator generates a reference signal. A reference signal receiver is mounted on a unit set as an active or standby unit and receives the reference signal. A timing signal generator divides the frequency of the received reference signal by means of a frequency divider/counter to generate a timing signal. A count holder holds the count value of the frequency divider/counter. The bus connects the units and the central processing unit. A count receiver receives, via the bus, the count value from the count holder of the active unit. A count updater updates the count value of the frequency divider/counter to the count value received by the count receiver.

Abstract: A plug-in card for an optical transmission apparatus includes a J1 byte generating unit. The J1 byte generating unit sends information on on-use side J1 byte data to a plug-in card at a spare side in a redundant structure when the plug-in card operates as an on-use side plug-in card. The J1 byte generating unit receives information on on-use side J1 byte data from a plug-in card at the on-use side when the plug-in card operates as a spare side plug-in card. Based on the information, the J1 byte generating unit matches spare side J1 byte data to the on-use side J1 byte data. The plug-in card also includes a B3 byte calculating unit that operates in a similar way as the J1 byte generating unit does in processing B3 byte data.

Abstract: A read address from a memory and a write address to the memory are transmitted from a VT pointer circuit on an active side to a VT pointer circuit on a standby side in order to eliminate a difference between pointer values of the VT pointer circuits on the active and the standby sides, which is caused by a difference between the phases of the read address from the memory and the write address to the memory of the VT pointer circuits on the active and the standby sides, and the read and the write addresses on the standby side are overwritten with the transmitted address values. As a result, the address values can be made to match both on the active and the standby sides, and also the pointer values can be made to match.

Abstract: A transport systems is equipped with a burst error detecting unit that monitors a predetermined byte, which is specified in advance in a frame to be monitored, in a transmission signal having header information and data information multiplexed into the frame in bytes. The burst error detecting unit detects a burst error based on a change in a state of occurrence of a bit error in the predetermined byte in a predetermined time window.

Abstract: The invention relates to a subordinate apparatus and a superordinate apparatus. The object thereof is to surely detecting an erroneous connection in a wiring between these apparatus and identifying an erroneously connected cable. A subordinate apparatus has an identifier acquiring section acquiring an identifier that is granted by a superordinate apparatus via a communication link that is formed via a first cable. When granted a new identifier via the communication link, the identifier acquiring section makes a first judgment as to whether there is an identifier granted prior to the new identifier. The identifier acquiring section nullifies the new identifier if there is an identifier granted prior to the new identifier.

Abstract: An object of the invention is to provide a diagnosis method for standby systems in an optical ring network having a redundant configuration, which can confirm normal states of standby systems in all optical transmission apparatuses on the network, even during operations of active systems. To this end, in the present diagnosis method for standby systems, when a diagnosis start command is given to an arbitrary optical transmission apparatus on the network, the optical transmission apparatus provides a false signal to a standby system unit to diagnoses an operation state thereof, and transmits the result to the optical transmission apparatus on the downstream side by utilizing overhead information in the active system optical channel.

Abstract: An optical transmission technique for a ring transmission system that can transmit time-division-multiplexed optical signals in dual directions. An optical transmitting apparatus comprises a data link reading section, a topology creating section, a data link writing section, a squelch table creating section, a squelch table, an RIP table creating section, an RIP table, a node recognizing section, an east-side receiving unit, an east-side transmitting unit, a west-side transmitting unit, and a west-side receiving unit. When a transmission route is switched at plural positions, the squelch table and the RIP table are automatically created as soon as a crossconnect is set. With minimum setting, the ring transmission system can be normally operated without increasing the number of setting items, the squelch table can be created at a high speed using existing hardware, and an alarm can be automatically transmitted from a secondary node until each table is created.

Abstract: A transport systems is equipped with a burst error detecting unit that monitors a predetermined byte, which is specified in advance in a frame to be monitored, in a transmission signal having header information and data information multiplexed into the frame in bytes. The burst error detecting unit detects a burst error based on a change in a state of occurrence of a bit error in the predetermined byte in a predetermined time window.

Abstract: In a light transmission equipment which can generate a desired concatenation signal from a maximum concatenation signal standardized in a synchronous transmission mode, a master and a slave circuit for clock change are provided respectively inputting at least two data at a maximum transmission rate based on a concatenation standard of a synchronous transmission mode obtained by dividing a desired transmission rate not prescribed in the concatenation standard to perform a concatenation control to the slave circuit by control information from the master circuit side.

Abstract: In an error correcting method and an apparatus therefor using Hamming codes, a frame regulated by a synchronous network is divided into L blocks in the direction of row. Preferably, information bits and check bits are allocated to a payload portion and non-defined bits of an LOH portion, respectively. More preferably, the information bits and the check bits are divided into M sub blocks to form a Hamming code block. In addition, a code error correcting means rearrange each Hamming code block per bit and further preferable, a syndrome register with a plurality of banks operates an error syndrome of the Hamming code block, and based on the operation result, the code error correction of the Hamming code block is performed by a bank switchover.

Abstract: A TSA circuit which receives as input upper side incoming transmission data from a super high speed ring network and lower side incoming transmission data from a high speed ring network and outputs upper side outgoing transmission data to the super high speed ring network and lower side outgoing transmission data to the high speed ring network, provided with a time slot assignment function block which has a time switch and a space switch and produces outgoing transmission data obtained by switching channels for the incoming transmission data in units of bits, whereby high speed and large volume incoming transmission data can be processed for time slot assignment (TSA), interchanged in channels, and sent out as outgoing transmission data by a relatively small sized circuit configuration.

Abstract: In an error correcting method and an apparatus therefor using Hamming codes, a frame regulated by a synchronous network is divided into L blocks in the direction of row. Preferably, information bits and check bits are allotted to a payload portion and an LOH portion of non-defined bits. More preferably, the information bits and the check bits are divided into M subblocks to form a Hamming code block. In addition, a code error correcting means rearrange each Hamming code block per bit and further preferably, a syndrome register with a plurality of banks operates an error syndrome of the Hamming code block, and based on the operation result, the code error correction of the Hamming code block is performed by a bank switchover.

Abstract: The present invention relates to a guard apparatus for avoiding the malfunction of a communication apparatus due to an error in the received data in the specific location of a frame on the receiving side of an optical communication system using a SONET/SDH network. If a B2 error, a frame pattern error or an out-of-frame is detected for a received frame, this guard apparatus stops the operation for tri-stage protection for the data of the K1 and K2 bytes, and outputs data outputted for a received frame received one frame before the above-mentioned received frame. If these errors are not detected, the guard apparatus selects and outputs the non-protected data of the K1 and K2 bytes in the above-mentioned received frame. Thus, the extraction of data with an error due to an optical degradation can be avoided and thereby the malfunction of a communication apparatus in an optical communication system can be avoided.

Abstract: A time slot assignment circuit capable of performing channel setting with a high efficiency and with a high degree of freedom of channel setting with respect to a large volume of transmission data and in addition having a small circuit scale and low power consumption, provided a time switch provided with a transmission data memory into which transmission data is sequentially written and performing switching in a time domain with respect to the transmission data, a space switch for performing switching in a space domain with respect to an output thereof, an address control memory which outputs a channel setting address for controlling the two switches, and a channel setting information converting unit for converting a channel setting information from the outside to a channel setting address and an accessing address for the memory.

Abstract: An optical telecommunication unit includes a shielded case having a size adapted for mounting upon a standard open-rack frame, wherein the shielded case includes a rear panel carrying an interconnection pattern, a plurality of plug-in connectors provided on the rear panel at an inner side thereof in electrical connection with the interconnection pattern for holding plug-in units forming an optical telecommunication apparatus inside the optical telecommunication unit, wherein the optical telecommunication unit carries a plurality of interface connectors on the rear panel in electrical connection with the interconnection pattern for accepting external interconnection cables, and a rear cover is provided on the shielded case so as to cover the rear panel.

Abstract: A bidirectional line switch ring network wherein, when a fault occurs in the ring transmission line, a loopback is formed at the node adjoining the fault so as to loop back the line between a first optical fiber and a second optical fiber and therefore protect the line. The time slot numbers of the working line time slots and the time slot numbers of the line protection time slots allotted in the first optical fiber and the time slot numbers of the working line time slots and the time slot numbers of the line protection time slots allotted in the second optical fiber are set to be respectively the same. By this, the configuration and control of the hardware handling the loopback switching are simplified.

Abstract: A bidirectional line switched ring network having a path alarm indication signal (AIS) generation function, which is provided with ID writing means for writing, in the path overhead bytes of frames, IDs preassigned to add side nodes, tables for holding the correspondence between the IDs of add side nodes for sending frames to be dropped at drop side nodes and the number of the time slots to be used for the transmission of the frames, comparing means for comparing the IDs of the add side nodes read from the received path overhead bytes and the IDs in the tables corresponding to the number of the time slots used by the received frames, and path alarm indication signal generation means for generating and sending a path alarm indication signal (AIS) when the result of the comparison is that the two IDs do not match. By this, a path alarm indication signal can be generated at a high speed at the time of erroneous channel connection by simple hardware and a simple procedure.