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CDROM Forum · Drives/Hardware

#Need SCSI Y-Adapter

8 messages in this thread

#49341From: Barry LacterMay 27, 1993 3:18 PM

I have an NEC external CD-ROM drive (the CDR-36M). The drive has only one jack for a SCSI cable. It's a standard 50-pin female. I need an adapter that can turn that one jack into two. Does anyone know where I can a Y-adapter? Thanks for the help. …Barry

#49401From: Rob NixonMay 28, 1993 11:24 AM

Barry, That external CD-ROM with only one connector may mean that the drive is permanently terminated internally. If that is the case, you will only be able to use the drive as the last device on a SCSI daisy chain. If there were such a thing as a "Y" connector, I don't think it would work. I have a SCSI tape drive which is as you describe. It's a pain. -=Rob=-

#49411From: Barry LacterMay 28, 1993 1:39 PM

Thanks, Rob. Is there any way to tell whether or not it's terminated? …Barry

#49654From: Rob NixonJun 1, 1993 5:25 PM

Barry, Most SCSI devices are terminated with little flat resistor packs plugged in somewhere near the 50-pin connector at the back end. The resistors are about an inch long, 1/4 inch wide and have 8 or so little pins along one edge. They are usually black. A few devices have "active" termination, and use a switch, or software, to set termination. The Adaptec 1542C host adapter allows setting termination by software, so you don't have to open the box. Termination is required at each end of the SCSI bus, and nowhere else. Good luck, -=Rob=-

#49446From: Charlie BenetMay 29, 1993 2:43 AM

Why don't you think a Y-cable (if you could find one) would work ??? This is exactly what an internal SCSI cable IS — it's one 50-conductor cable with many female plugs on it — you just make sure the last drive in the chain is terminated.

#49499From: Rick WarnerMay 30, 1993 10:35 AM

>>Why don't you think a Y-cable (if you could find one) would work ??? This >>is exactly what an internal SCSI cable IS This is not correct. A SCSI cable does not do a 'Y' at any point. It is an 'I' with a device at each end and possibly other connectors inserted along it. Or you could use a road analogy; a SCSI cable is a straight stretch of highway with a beginning and an end, with possibly a few pullouts, but NO forks. – rick –

#49688From: Charlie BenetJun 2, 1993 3:01 AM

Yep!!! I take it back as to the Y-stuff — your I-analogy is MUCH better. In any case if you COULD find an external cable with a CENTRONICs-50/DB-25 at either end and one in the middle it should work. A good project with a soldering iron!!!… -charlie-

#49838From: Charlie BenetJun 4, 1993 12:44 AM

Believe it or not, I was thumbing through a MISCO catalog that I received at work and I found that there WAS such a thing as a Y-SCSI cable — actually I think it's just a double Centronics-50 connector with a tap out to a DB-25 connector (which some SCSI devices accomodate, especially on the MAC). I don't know if that's what you want.