Abstract: The station side terminal device of the present disclosure includes: plural terminal devices, each including a buffer section including a through queue and one or more switch queues that temporarily stores packets, and a subscriber side terminal device assignment section that causes unicast packets addressed to switching target subscriber side terminal devices and packets for switching targets that are addressed to all of the subscriber side terminal devices to be stored in a switch queue, and causes unicast packets addressed to non-switching target subscriber side terminal devices and packets for non-switching targets addressed to all of the subscriber side terminal devices to be stored in the through queue; and a terminal device assignment section that transmits obtained unicast packets and obtained packets addressed to all of the subscriber side terminal devices to the terminal device designated by the packets.

Abstract: The station side terminal device of the present disclosure includes: plural terminal devices, each including a buffer section including a through queue and one or more switch queues that temporarily stores packets, and a subscriber side terminal device assignment section that causes unicast packets addressed to switching target subscriber side terminal devices and packets for switching targets that are addressed to all of the subscriber side terminal devices to be stored in a switch queue, and causes unicast packets addressed to non-switching target subscriber side terminal devices and packets for non-switching targets addressed to all of the subscriber side terminal devices to be stored in the through queue; and a terminal device assignment section that transmits obtained unicast packets and obtained packets addressed to all of the subscriber side terminal devices to the terminal device designated by the packets.

Abstract: An optical communication system has two or more active interfaces, each controlling the transmission and reception of optical signals between a communication network and one or more subscriber terminals according to control information pertaining to the individual subscriber terminals. The control information used by all the active interfaces is stored in a memory. The optical communication system also has a standby interface that is functionally equivalent to the active interfaces, and an optical switching apparatus that switches data transmission paths among the network, the active and standby interfaces, and the subscriber terminals. If a fault is detected in an active interface, the standby interface extracts the control information of the faulty interface from the memory, and the optical switching apparatus switches the data transmission paths so that the standby interface replaces the faulty interface.

Abstract: An optical communication system has two or more active interfaces, each controlling the transmission and reception of optical signals between a communication network and one or more subscriber terminals according to control information pertaining to the individual subscriber terminals. The control information used by all the active interfaces is stored in a memory. The optical communication system also has a standby interface that is functionally equivalent to the active interfaces, and an optical switching apparatus that switches data transmission paths among the network, the active and standby interfaces, and the subscriber terminals. If a fault is detected in an active interface, the standby interface extracts the control information of the faulty interface from the memory, and the optical switching apparatus switches the data transmission paths so that the standby interface replaces the faulty interface.

Abstract: In an optical transmission system, an optical output control device for an optical wavelength multiplexer includes a wavelength generation circuit for generating wavelength data representative of a wavelength &lgr;1 or &lgr;2 and implemented by a decimal number or a binary number. A wavelength administrative byte generation circuit receives the &lgr;1 or &lgr;2 wavelength data and transfers it to a wavelength administrative byte insertion circuit and a wavelength administrative byte detection circuit. The wavelength administrative byte insertion circuit inserts the &lgr;1 or &lgr;2 wavelength data in the positions of bytes D1 and D2 of a high-speed signal, transforms the resulting multiplex signal to a corresponding optical signal, and delivers the optical signal to an optical multiplexing circuit. The multiplexing circuit multiplexes high-speed optical signals respectively having the wavelengths &lgr;1 and &lgr;2 and feeds the resulting multiplex high-speed optical signal to an optical amplifier.

Abstract: Transmission error correction is performed by generating an extremely small number of error correction code bits even when the value of N in STM-N (Synchronous Transport Module Level N) becomes large. The sending signal input terminal receives four AU-4 signals, and the serial/parallel conversion circuit converts the signals to eight parallel signals. The number of check bits required for encoding eight parallel bits is 14. The error correction encoder provided for the first bit divides a received data stream by a polynomial and sends the resulting remainder to the check bit output terminal 1 as the check bit. Each of the error correction encoders calculates the check bits of data streams using the polynomial and sends the results to check bit output terminals 2-8. The {n, k} shortened Hamming code is executed for each bit by inserting these check bits into undefined bytes in the multiplex-section overhead (MSOH).