Abstract: A communication device includes a reception buffer configured to receive a pulse signal cyclically transmitted from a transmission source device via a transmission line; a branch circuit configured to generate a branch pulse signal by branching the pulse signal; a delay circuit configured to add a predetermined delay time to the generated branch pulse signal; and a transmission buffer configured to transmit the branch pulse signal to which the predetermined delay time was added to the transmission source device via the transmission line.

Abstract: A communication device includes a reception buffer configured to receive a pulse signal cyclically transmitted from a transmission source device via a transmission line; a branch circuit configured to generate a branch pulse signal by branching the pulse signal; a delay circuit configured to add a predetermined delay time to the generated branch pulse signal; and a transmission buffer configured to transmit the branch pulse signal to which the predetermined delay time was added to the transmission source device via the transmission line.

Abstract: A method of determining a transmission route for optical signals in an optical signal transmission system comprising a transmitter for optical signals, a receiver for the optical signals, and repeaters for repeating the optical signals transmitted from the transmitter to the receiver, and having transmission routes between the transmitter and the receiver, wherein the numbers of the wavelength components of the optical signals that has been in-use in each section defined to each of the transmission routes, the acquired numbers of wavelength components are compared among the transmission routes, and one of the transmission routes having the minimum number of wavelength components is determined as the transmission route used to set the line.

Abstract: A method of determining a transmission route for optical signals in an optical signal transmission system comprising a transmitter for optical signals, a receiver for the optical signals, and repeaters for repeating the optical signals transmitted from the transmitter to the receiver, and having transmission routes between the transmitter and the receiver, wherein the numbers of the wavelength components of the optical signals that has been in-use in each section defined to each of the transmission routes, the acquired numbers of wavelength components are compared among the transmission routes, and one of the transmission routes having the minimum number of wavelength components is determined as the transmission route used to set the line.

Abstract: If wavelengths ?a and ?b are dropped in NE (Network Equipment) 2 and a wavelength ?c is made Through, and all of wavelengths are made Through in NE3 in a certain time period, a route from NE1 to NE2, a route from NE2 to NE4, and a route from NE1 to NE4 are established. If a user who uses the wavelength ?a from NE1 to NE2, and a user who uses the wavelength ?b from NE2 to NE4 do not use the routes in another time period, and if another user desires to use a route from NE1 to NE3 and a route from NE3 to NE4, the routes are reestablished in a way such that the wavelength ?a is converted into the wavelength ?b and made Through in NE2, and the wavelength ?b is dropped and added in NE3.

Abstract: An optical wavelength division multiplexing transmission system is disclosed, in which it is possible to establish a new additional line readily, without affecting lines. The optical wavelength division multiplexing transmission system has a plurality of cascaded transmission devices respectively having optical wavelength division multiplexing functions, and each of the plurality of transmission devices includes a management section for managing used and unused wavelengths, and the respective transmission devices located in a section where a new additional line is to be established allocate an unused wavelength to the new additional line, on the basis of the unused wavelength information held by the management sections, thereby ensuring a route going to the target transmission device.