IBM 6094-010 "Dials" protocol?

Picture here: https://i.imgur.com/ClCw070.jpg Does anybody know how to talk to this thing? I've got one of these devices but I don't have a reference for the protocol. It's a serial device so it's probably not terribly complicated, but trying to figure it out by throwing random bytes at it might take a few years. SA23-2780-01 - "Option Instructions IBM 6094 010 Dials for AIX" should have the description of the protocol, but I can't find this document anywhere. https://www.ibm.com/support/knowledgecenter/en/ssw_aix_71/com.ibm.aix.files… gives some hints on how it is programmed - in particular it alludes to "setting granularity" (sensitivity) which would be in addition to reading the dials. Somebody with access to an AIX box and that "special file" might be able to dig up the commands. I know IBM has professional archivists so I can try them for the document referenced above if I can't find it other ways. And I could probably find the micro-controller inside, hope the ROM is readable, and try to disassemble that, but that would be a last ditch effort. Regards, Mike