Abstract: The invention relates to a plug-and-socket connection for connection of a first apparatus via a cable which contains electrical connections and optical connections to a second apparatus or a device, the first apparatus having an apparatus socket and the device having a device socket for accommodating the plug of the cable, characterized in that the apparatus socket and also the device socket having means to convert preferably a part of the electrical signals which were applied on the input side to the apparatus socket into optical signals when a controller/transceiver which is provided in the apparatus socket ascertains that the connected cable has optical lines and that the device socket or apparatus socket is made for receiving optical and electrical signals.