the plug connector extends along a main axis and at least one optical waveguide end terminates in a connector housing . locking parts , which are preferably symmetrically placed on the narrow sides of the connector housing , each have a detent element . an actuating element can be actuated to displace the detent elements from a locking position into a release position . the direction of displacement of the actuating element extends substantially perpendicular to the main axis of the plug connector and it is different from the direction along which the detent elements move between the locking and release positions .