On Tue, Feb 25, 2020 at 4:20 PM Alan Perry via cctalk <cctalk@classiccmp.org> wrote: > > > As previously discussed here, I have a Sun 3/260 that connects to a Sun > external storage subsystem containing two 8” SMD drives. The external cabling > is a 0.7m D-sub 25-pin (male both ends) data cable for each drive and a > paired set of 0.7m D-sub 25- and 37-pin (male both ends) command cables. > These cables are straight through connections between internal ribbon cables > from the drives (CDC 9720-368 and Fujitsu M2372) to the controller board > (Xylogics 451 on a VME adapter). > > For reasons described below, I have been unable to buy the original Sun > cables. Should off-the-shelf D-sub 25- and 37-pin cables work? I guess > electrical shielding/noise could be a concern?
A lot of SMD cabling was that twist-n-flat ribbon cable, the twisted pair stuff with flat sections to crimp IDC connectors onto. My guess is that provided to arrange it so that the external cable twisted pairs match up with the internal cable ones (or if the internal cables are just plain ribbon cable, so that each twisted pair carries a signal and its inverse (if you see what I mean) then it will work fine with such cables. I wouldn't try to use commercial DB25 and DC37 'round' cables as there's no knowing what is going on inside the cable. But if you can get some multiple twisted pair cable you could solder it to the right connectors (again making sure a signal and its inverse end up on a twisted pair). More work than the twist-n-flat cable though. -tony
