The HP 715/80 workstation has an unusual port for input devices that
requires the use of an adapter box: the HP HIL A4022-62005. This module
sells at an insane price, even without its cable, so the only reasonable
thing to do was to make one myself.
At the back of the station is a socket for a modular connector, much like a
network plug, but with 10 pins instead of 8.
If you look closely, you can see that it is also keyed on the left, certainly
to prevent anyone plugging a network cable in there.
Thanks to nater1217 on the VCFed forum, the pinout is
known!
and has also been submitted to pinouts.ru.
Many thanks also to Anders Gustafsson for sharing his Adventures with HP HIL,
especially for the part numbers of compatible connectors.
The good news is that, in addition to HP HIL, PS/2 keyboard and PS/2 mouse signals
are both directly available on this connector, and the adapter box doesn't need any
logic. This was confirmed with a quick prototype on breadboard:
Now I know it's working, but I'd rather have all that in a nice box, so I designed
a PCB that would fit in a small 10cm by 6cm box.
The schematic is extremely simple:
And the PCB isn't very complex either:
Note that I have included the HIL connector, but I give absolutely no guarantee that
it will work, this is entirely untested and the order of the pins could very well be
swapped! Use it at your own risk.
The gerber files were then sent to JLCPCB and the printed circuit boards arrived after
a few days.
Assembly was straightforward. In hindsight, I wish I'd used a right angle pin header
instead of soldering the wires directly to the board, but I don't have any in stock.
Well, I have ordered some, and I can always change it later. (The box is too small for
vertical pin header).
The cable I used comes from a PS/2 extension cord and has only 6 conductors (plus
shielding, that I didn't use); that's just enough to get the two PS/2 connections
working!
The two holes are used to firmly secure the cable with a zip-tie.
Enjoy a few more pictures of the circuit assembled and put in its box.
The schematic was made with Lepton EDA
and the PCB with pcb-rnd.
You can download an archive of the sources of the project
or go to the project page on framagit.