Electrotechnical, electronic, optoelectronical, optoelectronic and optical apparatus and construction elements; connectors, couplings and connection-elements for the connection of electrical wires or optical fibers with optical fibers.; Electrotechnical, electronic, optoelectronical, optoelectronic and optical apparatus and construction elements; connectors, couplings and connection-elements for the connection of electrical wires or optical fibers with optical fibers.