There is a general trend in electrical engineering towards greater flexibility, function integration and miniaturisation, which implies a change in the specific requirements for PCBs. The relevant connector systems in particular, which previously only had to provide a reliable contact with some corrosion-resistance, must now be rather exceptional. Every fraction of a millimetre counts on PCBs these days. High density is required, as the complexity of the functions to be carried out in the smallest possible area is continuing to grow. This also applies to creation and disconnection of contacts. Time and costs determine the direction of development in this discipline. People want quick, flexible and automated assembly and the simplest possible ways to create connections, sometimes by having parts click into place automatically.