 Do Cat6 cables work with Cat5? Cat6 and Cat5e systems will each have the same termination standards. Furthermore this will be for the cable cores, core colors, patch panel, modules and termination plugs. Therefore all Cat6 elements will plug into Cat5e systems and vice versa. However the performance of the overall cabling system will only be as good as its weakest part. Thus plugging Cat6 components into a Cat5e system will only retain the performance of a Cat5e link. Furthermore plugging Cat5e elements into a Cat6 link will reduce it to a Cat5e performance.