A plug connector has a housing body, and a retaining cage is locked in place inside the housing body. At one end the retaining cage encloses a contacting element for electrically contacting a conductor of a cable to be attached, and at the other end the retaining cage encloses the cable sheath of the cable to be attached. Coupling elements for reversible connection of a further plug connector having an identical housing body are provided externally on the housing body on both sides thereof. Fixing elements for fixing the plug connector onto a mounting rail are provided externally on the housing body.