Abstract: The present invention relates to a wavelength multiplexing apparatus for multiplexing and/or demultiplexing a plurality of optical signals in the wavelength region and a signal conversion apparatus for interfacing a transmission line corresponding to any of the optical signals with the wavelength multiplexing apparatus. By using these apparatus according to the invention, the signal to be a reference for synchronization between the wavelength multiplexing apparatus and the signal conversion apparatus is reliably delivered via an existing optical transmission line therebetween, without the reduction of transmission quality and the limitation on modulation systems. Therefore, in an optical transmission system with the present invention applied thereto, it is possible to meet conditions for office establishment and arrangement of the apparatus and satisfy the demands for maintenance/operation flexibly and at a low cost. Further, service quality and reliability are maintained at high levels.

Abstract: An apparatus having n-number of working cross-connects for cross-connecting an n-bit input signals arriving from a plurality of input paths on a per-bit basis; n-number of first logic circuits for calculating the exclusive-ORs of each said n-bit and applying outputs to a standby cross-connect for providing outputs; n-number of second logic circuits for calculating the exclusive-ORs of said output signals from each of said working cross-connects and from the single standby cross-connect; and third logic circuits for selecting output signals of said working cross-connects and outputs of the second logic circuits. The apparatus detects the occurrence of an abnormality in working cross-connects by monitoring the outputs of the second logic circuits, identifies the faulty cross-connect by successively turning off one of the n-inputs to the first and second logic circuits, and select outputs from the second logic circuits instead of from the faulty cross-connect by using the third logic circuits.

Abstract: Disclosed is a cross-connect apparatus having n-number of working cross-connects for cross-connecting, on a per-bit basis, n-bit input signals that arrive from respective ones of a plurality of input paths; n-number of first logic circuits for calculating the exclusive-ORs of the n bits of each input signal and applying their outputs to a standby cross-connect; n-number of second logic circuits for calculating the exclusive-ORs of signals output from the n-number of working cross-connects and from the single standby cross-connect; and third logic circuits having a function for selecting output signals of the n-number of working cross-connects and outputs of the second logic circuits.

Abstract: The present invention relates to a wavelength multiplexing apparatus for multiplexing and/or demultiplexing a plurality of optical signals in the wavelength region and a signal conversion apparatus for interfacing a transmission line corresponding to any of the optical signals with the wavelength multiplexing apparatus. By using these apparatus according to the invention, the signal to be a reference for synchronization between the wavelength multiplexing apparatus and the signal conversion apparatus is reliably delivered via an existing optical transmission line therebetween, without the reduction of transmission quality and the limitation on modulation systems. Therefore, in an optical transmission system with the present invention applied thereto, it is possible to meet conditions for office establishment and arrangement of the apparatus and satisfy the demands for maintenance/operation flexibly and at a low cost. Further, service quality and reliability are maintained at high levels.

Abstract: A transmission system having an uninterrupted switchover function for a plurality of lines is disclosed. The aims are to prevent unnecessary switchover and to provide high quality transmission system even using low quality lines with a minimal hardware configuration of memories and a control circuit. On the transmitting side, a pulse for phase synchronization is inserted at the top of each signal frame. Such frame signals are branched to transmit on a plurality of lines. On the receiving side, an alarm or error in signals from lines is detected on a frame basis. Then, a line switchover is carried out at the unit of a frame after frame phases are synchronized. To synchronize the frame phases, elastic memories for producing variable amount of delay are used in addition to fixed-amount delay circuits. This enables to insert a sufficient amount of delay to generate required timings for detecting errors, controlling and performing a switchover etc.

Abstract: A transmission system for transmitting data of a synchronous digital hierarchy SDH frame includes a transmission terminal, a transport terminal and a reception terminal linked together by a working channel line and a protection channel line in a redundant structure. Each of the transmission terminal and the transport terminal includes an alarm indication insertion unit which inserts an alarm indication in the SDH frame, the alarm indication indicating whether a related channel line has failed. The SDH frame containing the alarm indication is transmitted to the reception terminal prior to transmission of the data on the related channel line. The reception terminal includes a control unit which outputs a selected one of the SDH frame on the working channel line and the SDH frame on the protection channel line in response to the alarm indication received by the control unit.

Abstract: An apparatus for establishing synchronization between transmission signals transmitted from a signal source of a sending end to a receiving end via regular and alternative lines in a network using a transmission system such as the SDH and SONET. In the sending end, the present invention inserts a FP signal in the multiplexed information of the signal output from the signal source.

Abstract: A system for controlling signal transfer between a plurality of devices, for controlling the transfer of signals between a main device having processors packaged therein and a subsidiary device having units packaged therein, includes a multiplexer section on the main device side for multiplexing signals from a control system processor and a monitor system processor of the main device; a demultiplexer section on a subsidiary side for demultiplexing the multiplex signal from the multiplexer section on the main device side and distributing it to the units of the subsidiary device; a multiplexer section on the subsidiary device side for multiplexing the signals from the units of the subsidiary device; and a demultiplexer section on the main device side for demultiplexing the multiplex signal from the multiplexer section on the subsidiary device side and distributing it to the control system processor and the monitor system processor.