A module essentially includes a module housing, into which is introduced a lead frame. An electro-optical transducer is mounted on the lead frame. The interior of the module housing is filled with a transparent potting compound. A plug receptacle part is moulded onto the outer housing wall and has a defined outer contour. Situated in the interior of the plug receptacle part is an optical waveguide piece, which proceeding from the surroundings of an outer area of the plug receptacle part, extends through the interior of the plug receptacle part and through a housing opening right into the housing interior. The optical waveguide piece is optically coupled to the electro-optical transducer. An optical waveguide plug interacting with the module has a sleeve-shaped plug section corresponding to the plug receptacle part.