A cable backplane system includes a backplane having a plurality of openings extending between a front and a rear of the backplane. The backplane has mounting locations proximate the openings. Mounting blocks are coupled to the front of the backplane at corresponding mounting locations. The mounting blocks are secured to the backplane by fasteners. A cable rack is coupled to the rear of the backplane and has a tray with a frame surrounding a raceway and spacers coupled to the tray. The spacers hold corresponding cable connectors and are secured to corresponding mounting blocks to position the spacers and cable connector assemblies relative to the backplane. The cable connectors are received in corresponding openings in the backplane and are held in position relative to the backplane by the spacers and mounting blocks.