🚀 go-pugleaf

In <31806D84.6E6B5EB8@mail.utexas.edu> Andrew Litt <ajlitt@mail.utexas.edu> writes:

>Is there any easier way of making a standard SCSI connection to my Sun?
>Preferrably something that doesn't require a hard to find and expensive
>cable? TIA...

Yes. T&B Ansley make insulation-displacement connectors (IDC - ie. crimp
on) in the 50-pin 'D' variety. They make two types - one with the plug and
socket made just of their trademark light-blue plastic, and a more
expensive (but better for SCSI purposes) one with a pressed metal screen
over the plastic for improved shielding, etc. 

These connectors aren't cheap compared to the solder-type, but you can
combine these IDC connectors with special twist-n-flat ribbon cable (which
has short flat sections every 18" or so along the ribbon cable (where you
crimp on connectors), while between these flats each pair of wires is
twisted, as is required for SCSI since each signal line is effectively a
'transmission line' and needs good ground equalisation to reduce RFI
effects.

This type of ribbon cable is also more expensive that the normal grey
stuff, but the grey stuff will radiate RFI out of your computer in
enormous quantities, and since 3/60's are already only class A rated
instead of class B by the FCC for electrical emissions, we need to
minimise RFI as much as possible. 

I have made external SCSI cables for my Sun's (desktop and rackmounted
ones) using these T&B connectors and the special ribbon cable (also a T&B
product I think?), and there are no significant RFI problems. If you buy a
bunch of connectors, along witha slab of cable, you can make some money by
building up cables for your friends! 

If you are going to plug the other end of your cable into a box with a
50-pin 'D' socket, just make sure pin 1 lines up with the right wire of
the cable at each end and crimp away. If you need to use a 50-pin
'Centronics'-style connector at the other end, the same applies. Just line
up pin one of each connector with the same wire in the ribbon cable and
crimp... instant SCSI cables. 

Do not try soldering up a cable unless you are very, very patient. It's
not the same as soldering 50 pads on a circuit board, because you have to
cut, strip, twist and tin the multi-strand conductor for each of the 50
wires before even thinking about starting to solder them to the back of
the connector.  Definitely not for the faint-hearted! 8-)

Regards,

Craig.
-- 
             Craig Dewick. Send email to 'cdewick@jedi.apana.org.au'
                 The Core Matrix Foundation - Sydney, Australia
                        http://jedi.apana.org.au/core.html
 Always striving for a secure long-term future in an insecure short-term world