Abstract: The invention relates to an optical coupling unit for an arrangement for sending optical signals, including a base unit, a light path formed between a light input and a light output of the base unit and configured to transmit light received via the light input to the light output, an outer light path section included in the light path, which section extends outside the base unit and into which the light transmitted along the light path emerges from the base unit via a light exit and from which the light after passing through the outer light path section enters again into the base unit via a light entry, and a light decoupling element, which is formed in the light path by means of at least one beamsplitting surface coating and configured to decouple a portion of the light transmitted along the light path. Furthermore the invention relates to an arrangement for sending optical signals and to an optical transceiver.

Abstract: The invention relates to an optical coupling unit for an arrangement for sending optical signals, including a base unit, a light path formed between a light input and a light output of the base unit and configured to transmit light received via the light input to the light output, an outer light path section included in the light path, which section extends outside the base unit and into which the light transmitted along the light path emerges from the base unit via a light exit and from which the light after passing through the outer light path section enters again into the base unit via a light entry, and a light decoupling element, which is formed in the light path by means of at least one beamsplitting surface coating and configured to decouple a portion of the light transmitted along the light path. Furthermore the invention relates to an arrangement for sending optical signals and to an optical transceiver.

Abstract: An electrical circuit for controlling at least one electrical load and at least one function thereof by providing, in the active line of an AC circuit, a modulation switching circuit and a plurality of function keys series-connected with at least with the at least one electrical load and a demodulation unit upstream thereof.

Abstract: The invention relates to a method and apparatus for marking entrance and exit opening sites in opposite surfaces of a wall member of a perforation to extend therethrough and is provided, at one surface at a site corresponding to one of the entrance and exit openings with a wave signal transmitter and, at the other surface with a wave signal receiver responding to transmitted signals by rendering an indication of a maximum strength wave signal as a function of the location of the other of the entrance and exit opening. In a preferred embodiment, the receiver is mounted on a drill or the like at a predetermined distance from the axis thereof and the transmitter is provided with a cantilever provided with a marker spaced from the transmitter at a distance corresponding to the predetermined distance.