CompuServe Thread

Drive jumpers

2 messages in this thread
#63510From: Jamie SevereJul 23, 1992 4:41 AM
To any and all, I have a Fujitsu harddrive that is a model 2263HA which is a differential SCSI interfaced drive. I have been told that just by changing a few of the jumpers on the imbedded interface card that I can make it a Sequential drive (the type used by the Amiga) but no one knows which jumpers to change, and the tech manual won't tell. Since this is a used drive I need to know if anyone knows which jumpers to change? Please let me know if you do. Thanks in advance! Sid
#63590From: Don Curtis/SYSOPJul 24, 1992 2:17 AM
Sid, No, a differential drive can't be changed by just a jumper or two. Differential SCSI uses the difference between two signal lines to indicate a binary ON or OFF. Depends on which of the signal lines is more positive than the other line. Each signal line on a differential device can vary from -7v to +12v. They're called 'differential' devices because of the above signaling method. On the other hand, single ended (not 'sequential') drives use a single ended signaling scheme. That is, only one signal line carries voltage, the other line is a ground. The voltage on the signaling line varies between 0v and +5v. The grounds may be common (all attached to the same point) and in practice, generally are. But not only that…the pin assignments (besides the obvious differences in grounding) are different. So far more must be done than change a jumper or two. Don