RE: 56pin to 68 pin scsi converter

[Aaron Clow <AaronC cmj com>]

> From:	Eric Lee Green [SMTP:eric linux-hw com]
> 
> >>>As far as order goes, it does not matter as long as a) all the
> lines are properly terminated, and b) all the lines needed get to the
> final device on the bus. I've seen the little widget from Adaptec that
> you are talking about (which terminates the top half of the bus and
> passes on the low part of the bus), but that is a very expensive and
> somewhat clumsy solution. The best solution is a single long cable
> with 68-pin connectors, with a terminator on the end of the cable so
> that it does not matter what order you place the devices inbetween,
> and with 50->68 pin adaptors (look kind of like gender-changers)
> placed on all of the 50-pin devices (YES this is legal -- stubs of
> less than 4mm, which is what this looks like to the SCSI bus, are
> definitely legal in SCSI-land).<<<
> 
> This is pretty much what I'm using, and yes, it works just dandy... My
> motherboard has two UW connectors on it, plus one narrow SCSI
> connector. My problem was that I wanted the narrow SCSI to go to an
> EXTERNAL device (scanner) so I could get rid of the SCSI adapter that
> came with the scanner & free up an ISA slot for my Atari Portfolio PC
> Card Drive controller.
> 
> So the configuration is: I now have the narrow connector attached to a
> cable that runs to a connector on the back of my case (for external
> use), on Channel A. Attached to one of the UW connectors on the
> motherboard (Channel B) is a 68-pin UW cable that has four connectors
> on it. I have the second hitched up to my UW-SCSI Cheetah Hard Drive,
> the third to a SCSI-CD-R device with that gender-change type thingy
> that converts from 68-pin to 50-pin narrow, and the fourth attached to
> a SCSI CD-ROM drive with the same converter on it...
> 
> Works like a charm. I remember reading something about how you can't
> have the 50-pin devices first because of a high-bit getting lost...
> However, I have NOT read anything about narrow devices needing a
> special terminator when used at the end of a chain that contains
> 68-pin devices... Supposedly, you can just activate termination on the
> 8-bit device at the end of the chain.
> 
> In any case, everything works fine like this, no termination problems
> at all.
>  
> Aaron
> soundworks mail earthlink net