The invention relates to a connection block for a plug-and-socket connector. The plug-and-socket connector is suitable for the plug-and-socket connection of a data transmission cable with a plurality of electrical conductors. The connection block comprises: each electrical conductor of the data transmission cable, a connection contact element in a connection shell, wherein the connection contact element is composed of an insulation displacement contact or a piercing contact in each case, for contacting with the electrical conductor and the connection shell is shaped, such that the connection contact elements may not b introduced from the outside into the connection shell.