transition printed circuit boards and edge contact wafers are positioned back - to - back and disposed within slots of a diecast aluminum shell with which they are held in place by means of an outer housing . high - speed electrical cable is attached to conductive patterns on the transition printed circuit boards using flux - free methods . the resultant cable and connector are capable of high - speed operation and are still , nonetheless , capable of providing high - density connections to connectors on boards immediately adjacent to semiconductor chips .