It's a good idea to Google the subject before starting work so I don't waste time or risk breaking things.

I found this Hackaday post which led to a blog by "Electrosthetics" who has helpfully published lots of interesting historical information about amBX.

The most important pages for this project are here and here, where they provide pin-outs for the fan and wrist rumbler sockets on the original amBX controller. The connectors on my hardware are mirrored from the drawings in the blog post, so I'm sure the blog post is showing the receptacles. My custom controller will need to match these pin-outs.

I'm surprised to see that the wrist rumbler needs 15V. Hopefully it will be acceptable at 12V, because I was planning on only having one 12V power brick supplying power to my custom controller.

Fortunately the connectors aren't custom so I don't need to re-terminate the cables. I can just buy suitable receptacles.

• The fan connector is a 5 pin Mini-DIN. (The fans are identical - there isn't a specific left and right unit.)
• The wrist rumbler connector is an 8 pin Mini-DIN.