Abstract: Apparatus by which a maximum number (e.g. 16) of external high speed computer data storage devices (e.g. computer hard drives) that are housed within portable carriers can be efficiently connected to and concurrently operated from the same low voltage differential (LVD) SCSI bus of a host computer by eliminating the adverse effects (e.g. parasitic capacitance, impedance mismatch and signal distortion) that occur as a consequence of the stub length that is required to couple a data storage device to its SCSI bus. A U-shaped receiving frame is affixed to and enclosed by a chassis, and the portable carrier in which the data storage device is housed is slidably received in and removable from the receiving frame. An isolator board carrying a repeater chip is coupled to the backplane of the receiving frame so that the repeater chip is electrically connected between the SCSI bus and the data storage device within the portable carrier.