A plug connector for use with jacks of different standards has an insulating housing, a plurality of terminals and an adapter sleeve. Common resistors Ra and Rb for current limitation are interposed at some midpoint of the feeder lines 19 and 21. The substrate comprises a substrate body and wiring patterns, the substrate body has an upper surface on which the first chip and the second chip are mounted and a lower surface. The image acquisition unit is situated behind a protective element, so it is essentially inaccessible from the outside in a resting position, whereby a opening allocated to the image acquisition unit is provided in the protective element.