PERIPHERAL SHELF 2 clei The Peripheral Shelf Cardfile is a 19 rackmount shelf which has 12 universal card slots (UCS) and 2 common equipment card slots (X and Y). The X (and Y if redundant fabric is required) common equipment card slot is equipped with a Dual Hub or SHUB Card. The 12 UCSs are equipped with 0, 1, or 2 Control Cards and up to 10, 11, or 12 interface cards depending on the number of Control Cards installed. One Control Card is installed for non-redundant control, two for control redundancy, and zero if Control Cards have already been installed in another Peripheral Shelf of the 7470 system. A 7470 system can be equipped with up to 8 Peripheral Shelf Cardfiles for a total of 96 UCS's. This assembly contains a Telcordia CLEI (Common Language Equipment Identifier) label.