CompuServe Thread

#SCSI Cables

2 messages in this thread
#145524From: Robert LittleMay 14, 1994 12:40 AM
Just to get into an argument on standards…I guess. I've never read a spec from whatever standards body on SCSI, but it seems to me connectors are not required to be any single configuration. It's just the leads that are critical. Take RS-232, everybody calls a DB-25 an RS-232 connector when it's not, it's a DB-25. It's the most common implementation, but RS-232 over a DB-9 is still RS-232. It's not the connector it's the leads. But, it still pisses me off when you have to go out of your way to buy an odd cable that doesn't conform to the usual. If, however, those 40 leads don't contain the proper info on them, then it's not SCSI at all just some proprietary protocol that someone wishes to call SCSI. Robb
#145580From: Harry ManolopoulosMay 14, 1994 8:11 AM
Yes, connectors are specified in the SCSI standard. Since the SCSI bus is a terminated bus, it is sensitive to caable length, improper termination, and number of connectors. Before SCSI was SASI, and there are some SASI implementations still kicking around. As far as odd connectors go, for SCSI-1 on a 50 pin connector, 25 of those pins arg grounded. That's why you can use a DB-25. ATARI has an odd connector for SCSI. IBM has a miniature version of the centronics connector and the cable costs $150.00. Acculogic and some tape drive controllers have a miniature 50 pin connector which might be a db-50. Some devices have only one centronics 50 pin connector so they have to be at the end of the chain and possibly use a pass thru terminator which technically does not conform to SCSI standards. (Are we having fun yet?:)). A woman at work was trying to install OS/2 from CD-rom. She was getting all kinds of disk errors on the system (IBM with SCSI disk and SCSI CD-ROM). DO you have the CD-Rom terminated I asked? After she plugged in the terminator, everything worked fine. People new to SCSI do not understand that it is an external system bus, needs termination, and device addressing. Not quite plug and play. I try to buy all SCSI periphals so that I can share them with my AMIGA and PC equipment. HarryM