Plug connector for differential data transmission

A round plug-in connector has a connection side configured for contacting circuit boards. For transmitting several independent, differential signals, the plug-in connector includes electric contacts arranged in pairs, with each of four signal pairs being insulated from each other by a cruciform structure, and being arranged inside an electrically non-conductive round body surrounding the cruciform structure. An electrically conductive screen cross is surrounded by a cruciform contact carrier with accepting grooves in diagonally embodied internal edges for holding the electric contacts. The round body is pushed over the cruciform arrangement, and is surrounded by an electrically conductive housing. Connection ends of the electric contacts that are intended to be aligned precisely on a circuit board, via a positioning aid, are attached to the round body. The positioning aid includes respective bore holes for the connection ends of the electric contacts, which coincide with soldered bore holes on the circuit board.