For all single ended Ultra SCSI Wide you can have four devices on a 3 meter bus or eight devices on a 1.5 meter bus. Bus length includes the total lengths of cable from end to end. It is not the distance between any two devices.*** Forcing the ATTO ExpressPCI DC card to Fast/Wide changes the cable length and device limitations. Fifteen devices on a 3-meter cable are possible with Fast/Wide.NOTE: If you are at or above the max cable length then your machine may not boot or the devices will hang or possibly not show up at all.