Well thanks to everyone trying to help
The idea of the cdrom is a good one, it may have useful info altough it would really be great to have the manual for the future generations
There is very little info on this device and the few old messages you see are sometimesy wrong.
First of this unit works with a simple straight DB25 cable, the auto detect cable seems to have nothing special apart from a ferrite bead.
It's also quite fast (I suppose as fast as the scsi unit)
There are people saying it's a heap of cr$p but it's not worse than my regular LPT zip100 in any way, let's say they are both crappy plastic units
However the exact behaviour of the auto detect thing is mysterious, it's unclear wether or not the unit is terminated (conflicting info, I would say it is actively terminated) and it seems such details are covered in the instructions. There are also conflicting info about the limitations, for what I can see it can for example co exist with other devices in a scsi chain (but who would do that for retro computing in 2024 seriously)
All in all, it's not so bad, it's even working great here, with a SlimSCSI adaptec 1460 pcmcia on a laptop I've got SCSI Zipdrive speeds on laptops. There seems to be a pcmcia card from iomega themselves, maybe it was a scsi card of some sort.