A cable backplane system includes a backplane and a chassis supporting the backplane. A cable rack is coupled to the chassis and backplane. The cable rack includes upper trays and lower trays each having a frame and cable connector assemblies held by the corresponding frame. The upper trays have upper tray guides configured to interact with corresponding upper chassis guides on the upper support for supporting the upper trays relative to the backplane. The lower trays have lower tray guides configured to interact with corresponding lower chassis guides on the lower support for aligning the lower trays to the backplane. The upper trays have upper hanging guides and the lower trays have lower hanging guides coupled to corresponding upper hanging guides to support the lower trays with the corresponding upper trays relative to the backplane.