Abstract: A primary station equipment unit transmits, to a secondary station equipment unit, a message transmission enable signal granting transmission of a PST message from the secondary station equipment unit, when a predetermined period of time defined for transmission elapses after the primary station equipment unit transmitted a downstream PST message in a redundancy switching process corresponding to the secondary station equipment unit.

Abstract: A multiplexer includes an encoder. The encoder includes: flip-flop circuits that output two signals having a transmission rate of B/2 at a frequency of B/2, while holding signals of each signal; an adder that adds the respective signals output from the flip-flop circuits and outputs the added signal; and a delay unit that delays the signal output from the flip-flop circuit by the time of 1/B, with respect to the signal output from the flip-flop circuit, and outputs the signal delayed to the adder.

Abstract: A host station apparatus (10) generates band allocation information including identifications of slave station apparatuses (20-1 through 200-n) and types of data to be transmitted by the slave station apparatuses and posts the information to the plural slave station apparatuses (20-1 through 20-n). The plural slave station apparatuses (20-1 through 20-n) identify as to whether or not the band allocation information is band allocation information about the data types of the slave station apparatuses respectively, and when the band allocation information is band allocation information about the data types of the slave station apparatuses, they control to transmit data to the host station apparatus (10) according to the data types represented by the band allocation information.

Abstract: An FEC multiplexing circuit (2) has a configuration in which a first memory circuit (15) is arranged on the input stage of a first RS encoding circuit (16), a second memory circuit (17) is arranged on the input stage of a second RS encoding circuit (18), error correction encoding is performed by a combination of different data having two directions, and thereafter, error correction codes are multiplexed to generate an FEC frame. On the other hand, an FEC demultiplexing circuit (6) has a configuration in which a third memory circuit (42) is arranged on the output stage of a first RS decoding circuit (41), a fourth memory circuit (44) is arranged on the output stage of a second RS decoding circuit (43), error correction is performed by a combination of different data having two directions, and, thereafter, parallel data read from the fourth memory circuit (44) are multiplexed to reproduce original information data.

Abstract: An optical distribution network system includes an OLT; a plurality of ONUs; a first optical network and a second optical network, one of which connects the OLT with the plurality of ONUs; and a bandwidth controller. The bandwidth controller apportions the plurality of ONUs between the first optical network and the second optical network, assigns a predetermined transmission bandwidth to each of the plurality of ONUs, and accepts a bandwidth change of the transmission bandwidth. It solves a problem of a conventional optical distribution network system in that the maximum bandwidth available by DBA (dynamic bandwidth assignment) is equal to the total transmission bandwidth of working side minus the sum total of the minimum cell rates of the ONUs, and hence it cannot secure a large usable bandwidth for DBA, when congestion of bandwidth increase takes place among the plurality of ONUs.

Abstract: The data transmission and reception system comprises a data transmitter and a data receiver. The data transmitter generates and transmits a high-speed serial signal through a transmission path and the data receiver receives the serial signal. The data transmitter, when forming the frame for every tributary signal, inserts into the frame a frame bit indicating a boundary of the frame and, after having formed the frame, performs only a bit synchronization with respect to every tributary signal. On the other hand, the data receiver, for a respective tributary signal, stores a data indicated by the tributary signal and, in a timing based on a detection of the frame bit of the tributary signal and a reference frame pulse commonly issued between tributary signals, outputs the stored data to thereby perform the tributary synchronization.

Abstract: A multiplex transmission system of tributary signals multiplexes a plurality of tributary signals after adding to them frame information common to all the tributary signals and identification codes different for the individual tributary signals. This makes it possible to solve a problem of a conventional multiplex system of tributary signals in that the transmission rate is limited because it multiplexes a plurality of tributary signals with adding an SOH (section overhead) to generate an STM-N frame to be transmitted and received, which requires a considerable time.

Abstract: In an FEC frame structuring method, and an FEC multiplexer, the order of information is changed by a first interleaving circuit 32, a first error correction code is generated by an RS (239, 223) coding circuit 33, the order is returned to the original order by a first deinterleaving circuit 34, and a second error correction code is generated by an RS (255, 239) coding means 5. The second error correction code is decoded by an RS (255, 239) decoding circuit 11 to correct errors in the information, the order of information is changed by a second interleaving circuit 35, the first error correction code is decoded by an RS (239, 223) decoding circuit 36 to correct residual errors in the information, and the order is returned to the original order by a second deinterleaving circuit 37.

Abstract: The present invention has an object to obtain an optical signal quality supervisory device that supervises the quality of an optical signal simply, efficiently and with high accuracy without inviting an increase in cost, an increase in circuit scale and increase in power consumption. The bit rate of the optical supervisory channel is made lower than the bit rate of the optical main channel that is transmitted over an optical communication system, but the reception electric band width of a receiver that receives the optical supervisory channel is made equal to or wider than the reception electric band width of a receiver that receives the optical main channel. Also, the optical supervisory channel is made up of an SOH (section over head) frame to detect an error of the BIP (bit interleaved parity) byte of SOH, thereby supervising the quality of the optical communication system, in particular, the light wave network.

Abstract: A multiplexer includes an encoder (4). The encoder (4) includes: flip-flop circuits (4a, 4b) that output two signals having a transmission rate of B/2 at a frequency of B/2, while holding signals of each signal; an adder (4f) that adds the respective signals output from the flip-flop circuits (4a, 4b) and outputs the added signal; and a delay unit (4e) that delays the signal output from the flip-flop circuit (4b) by the time of 1/B, with respect to the signal output from the flip-flop circuit (4a), and outputs the signal delayed to the adder (4f).

Abstract: A primary station equipment unit 51 transmits, to a secondary station equipment unit 52, a message transmission enable signal granting transmission of a PST message from the secondary station equipment unit 52, when a predetermined period of time defined for transmission elapses after the primary station equipment unit 51 transmitted a downstream PST message in a redundancy switching process corresponding to the secondary station equipment unit 52.

Abstract: In an FEC frame structuring method, and an FEC multiplexer, the order of information is changed by a first interleaving circuit 32, a first error correction code is generated by an RS (239, 223) coding circuit 33, the order is rechanged to an original order by a first deinterleaving circuit 34, and a second error correction code is generated by an RS (255, 239) coding means 5. The second error correction code is decoded by an RS (255, 239) decoding circuit 11 to correct an error of information, the order of information is changed by a second interleaving circuit 35, the first error correction code is decoded by an RS (239, 223) decoding circuit 36 to correct a residual error of information, and the order is rechanged to an original order by a second interleaving circuit 37.

Abstract: A host station apparatus (10) generates band allocation information including identifications of slave station apparatuses (20-1 through 200-n) and types of data to be transmitted by the slave station apparatuses and posts the information to the plural slave station apparatuses (20-1 through 20-n). The plural slave station apparatuses (20-1 through 20-n) identify as to whether or not the band allocation information is band allocation information about the data types of the slave station apparatuses respectively, and when the band allocation information is band allocation information about the data types of the slave station apparatuses, they control to transmit data to the host station apparatus (10) according to the data types represented by the band allocation information.

Abstract: Slave stations (20-1-20-3) detect whether the buffer resident quantity in a buffer (25) is equal to or larger than a predetermined threshold. Each slave station comprises a buffer resident detection section (26) for notifying the detected results to a PT changing section (24). The PT changing section (24) changes the PT's in the ATM headers of the ATM cells which have been read out from the buffer (25) when there is a notification from the buffer resident detection section (26) that the buffer quantities are equal to or larger than the predetermined threshold.

Abstract: An optical switching system is implemented by providing a transmitting section with a preparatory transmitted optical signal selector and a working transmitted optical signal splitter, which are each implemented by a 1×2 optical space switch, and by providing a receiving section with a receiving optical switch which is implemented by a 2×2 optical space switch, and with a preparatory receiving optical gate which is implemented by a 1×2 optical space switch. This makes it possible to switch between the working system and preparatory system without employing any 4×4 optical space switch, thereby implementing a practical optical switching system without causing such problems as communication interruption during maintenance or impairment of transmission path working efficiency.

Abstract: In the optical multi-branch communication system, a parent device (1) and a plurality of daughter devices (2-1 to 2-n) having a redundant construction are connected to each other through a current system optical network and a preliminary system optical network. There are further provided a delay controlling unit which controls each delay amount on the current-system optical network and the preliminary system optical network, and a selection switching control unit which, if one of the daughter devices on the current-system optical network and the preliminary system optical network fails, switches the daughter devices (2-1 to 2-n) to another optical network that is working normally.

Abstract: An optical distribution network system includes an optical line termination and a plurality of optical network units. The optical line termination monitors a system switching request transmitted from each of the optical network units, and controls the switching between the working side and the standby side system of the optical network unit. It can solve a problem of a conventional system in that if the working side an optical network unit fails, and when its standby side is normal, even if the standby side of the other optical network units has a failure, they are switched from the working side to the standby side, thereby worsening the total system operation.

Abstract: An optical distribution network system includes an OLT; a plurality of ONUs; a first optical network and a second optical network, one of which connects the OLT with the plurality of ONUs; and a bandwidth controller. The bandwidth controller apportions the plurality of ONUs between the first optical network and the second optical network, assigns a predetermined transmission bandwidth to each of the plurality of ONUs, and accepts a bandwidth change of the transmission bandwidth. It solves a problem of a conventional optical distribution network system in that the maximum bandwidth available by DBA (dynamic bandwidth assignment) is equal to the total transmission bandwidth of working side minus the sum total of the minimum cell rates of the ONUs, and hence it cannot secure a large usable bandwidth for DBA, when congestion of bandwidth increase takes place among the plurality of ONUs.

Abstract: The data transmission and reception system comprises a data transmitter and a data receiver. The data transmitter generates and transmits a high-speed serial signal through a transmission path and the data receiver receives the serial signal. The data transmitter, when forming the frame for every tributary signal, inserts into the frame a frame bit indicating a boundary of the frame and, after having formed the frame, performs only a bit synchronization with respect to every tributary signal. On the other hand, the data receiver, for a respective tributary signal, stores a data indicated by the tributary signal and, in a timing based on a detection of the frame bit of the tributary signal and a reference frame pulse commonly issued between tributary signals, outputs the stored data to thereby perform the tributary synchronization.

Abstract: Multiplex communication system for transmitting different signals through a plurality of channels comprises a transmitter and a receiver. The transmitter comprises a transmitting section for multiplexing and transmitting the different signals through the plurality of channels, and an adder for adding channel identification signals for identifying the respective channels to the signals to be transmitted through the respective channels. The receiver comprises a setting device for setting a desired channel, a detector for detecting the channel identification signals from the signals transmitted from the transmitter, and a channel selector for selecting the channel signal preset by the setting device in accordance with the outputs of the setting device and the detector.