The invention relates to a co-axial plug-in-insertion connector which has a center conductor part, an outer conductor part, and an insulating part made of a dielectric material which holds the center conductor part co-axial to the outer conductor part, a coding housing being provided in which the outer conductor part and the center conductor part are arranged, the co-axial plug-in-insertion connector having an insertion end for connection to a complementary co-axial plug-in-insertion connector. Provision is made for the insulating part to be of a one-piece form with the housing.