Abstract: A sound transmission method is carried out in a data way system comprising at least one controller, more than two data input modules and more than two data output modules all of which are connected to one another by a series of data transmission lines making a single loop while linking them together. The data input modules and output modules each are given an address. One or some of the data input modules are constructed as a sound input module or modules, while one or some of the data output modules are constructed as a sound output module or modules. The controller specifies the addresses of the sound input and output modules more frequently than those of the other data input and output modules.

Abstract: An optical fiber data link system comprising a controller and one or more stations, all of which are connected to one another by a series of optical fibers providing a single loop as a whole. At least one data input module and/or one data output module is connected to each station. The controller includes a light receiving element, a serial-parallel converter, an circuit for generating an address/data indicating signal, an address setting circuit, a parallel-serial converter and a luminous element. Each station includes a light receiving element, a serial-parallel converter, an address/data distinguish circuit, a parallel-serial converter and a luminous element. Each data input module includes an address decoder, a comparison circuit, a switch circuit, a data latch circuit and one or more input terminals. Each data output module includes an address decoder, a comparison circuit, a switch circuit, a data latch circuit and one or more output terminals.

Abstract: An optical pulse receiving device converts an optical pulse signal into an electric signal, maintains a maximum value of the electric signal and sets a threshold voltage at one-half the maintained signal using a resistor divider. A comparison circuit compares the converted electrical signal with the threshold voltage and emits an output pulse on the basis of the comparison of the two signals. The output pulse is a square pulse with accurate timing.