The termination closes the electrical circuit .The last device in a SCSI chain must be terminated. SCSI devices in the middle must have termination disabled. The Minolta SCSI-Scanners has a switch for activating the termination (look at manual for details). The Quick Scan 35 needs an external termination (note the switch on the bottom of the Quick Scan 35 has to be set to on if your computer gives no voltage for the termination; for example: notebooks).