Wow, do you actually have 128 consoles to be served? Those things suck
some serious power.
This web page talks about how pinout for the cable to the H3104 cable
concentrator.
http://vax.sevensages.org/hw/cables.html (Search on H3104)
So, I'm acquiring some DECserver 550's, and as
I'd actually like to use
them as terminal/console servers, I need the pinout for the harmonica
block that would normally go on the end of the cable for these. I
don't seem to be able to find any documentation on pinout for them
using Google.