Use SCSI differential converters back to back to extend your SE or HVD SCSI bus longer distances. If you have a Singel Ended SCSI bus that needs to go from the maximum 20ft. with slow SCSI or 9ft. with Ultra speed SCSI, you can go back to back with Paralan's Differential Converters and get well over 120 ft. SCSI extensions. The exension is transparent to all computers, storage, software drivers and operating systems.