I have found the Omni and r-net programming manuals online before. I can't find anything on this device. Even pinouts or basic connection schematic would help. It could be that the device would just be recognized as a generic type that you program as one of the built-in device types. Without a complete r-net test setup (don't want to accidentally mess up the wife's chair) and programming tools I can't tell.
As I said, I got it as parts package. I took a chance because the price was worth it for the compact joystick alone. The seller (ebay) was just an individual who didn't know anything. It came with the arm shown in the picture below which had the compact joystick on the end. It could be as simple as it just rotated the joystick into place when the chair was turned on.
I doubt it's a proportional device. It just rotates a heavy duty shaft. It would need just a CW or CCW logic with built-in limit stops at the extremes, or maybe an encoder and some sort of feedback signal to tell the controller what angle it's currently at. The Omni manual mentions IOM (Input Output Modules) in the acronym list but does not address them in the text. Doesn't seem like it would be programmed as a SID type as it's not really in input device. However, the only useable connector on it is the 9 pin (no r-net). There is also a round DIN type connector so it could be that I am missing a box to bridge r-net to this device. Another possibility is that it's programmed as a dummy SID and the "output" is simply the 12V power on pin 7. That would complicate my programming plan if both Omni ports power up pin 7 as soon as power is turned on.
As far as programming, I'm aware there is dealer (Permobil) programming software available and OEM is sort of available if you know where to get it. But, I need an r-net to USB dongle, correct? I can buy the dongle from my Permobil dealer for not much more than they are currently asking on ebay. I'm guessing that includes an "official" license of the Permobil SW but I don't know if their dongle also works with OEM programming SW. If I want to try OEM SW, what version of the dongle do I need? I assume there is some sort of key embedded in either the dongle or the SW or someone would have hacked the r-net interface by now.